kitkras1.p65 3.12.98, 3:28 1 Black !" !"#$% &’()*+,-+./-00 12 &3322455" #22465% 55" &7588"9"8 #% ./+ :55 8 #$ %&" ’ ($’) ’*) ++, -’. /$- !"#$%" &’(!) *!+’,(!- .-)")$/$0(!$1%! ! " # $ 22--2(3!2$32 -4 ! "%&$ +#$) "’(( 5!2-# ) *(+,((&- -!6-%$! .#$ #&#!$-!- ,221(1222)-"!1$--!7 &$-2)(8))2$119)2/9(,)-"/9)1$-9-7 kitkras1.p65 3.12.98, 3:29 2 Black Digitalna verzija (pdf) je pod pogoji licence CC BY-NC-ND 4.0 prosto dostopna: https://doi.org/10.3986/9616182684. : kitkras1.p65 3.12.98, 3:29 3 Black 5 1 South China Karst I CONTENTS INTRODUCTION ............................................................................................................................... 7 1. KARST STUDIES OF YUNNAN 1.1. KARST OF YUNNAN....................................................................................................................... 11 Huang Chuxing, Liu Hong 1.2. THE LUNAN STONE FORESTS .................................................................................................... 18 Huang Chuxing, Martin Knez, Liu Hong, Tadej Slabe, Stanka ebela 1.3. LITHOLOGIC PROPERTIES OF THE THREE LUNAN STONE FORESTS (SHILIN, NAIGU AND LAO HEI GIN) ...................................................................................... 30 Martin Knez 1.4. STRUCTURAL CHARACTERISTICS OF SHILIN STONE FOREST ................................... 44 Stanka ebela 1.5. ROCK RELIEF OF PILLARS IN THE LUNAN STONE FORESTS ....................................... 51 Tadej Slabe 1.6. ROCK DISSOLUTION IN STONE FORESTS ........................................................................... 68 Janja Kogovek 1.7. HYDROLOGICAL CHARACTERISTICS OF THE TIANSHENGAN AREA ...................... 82 Metka PetriŁ 1.8. PHYSICAL AND CHEMICAL CHARACTERISTICS OF GROUNDWATER OF TIANSHENGAN AREA (The wider area of the tracing experiments) ................... 91 Janja Kogovek 1.9. TRACING TEST IN THE TIANSHENGAN AREA .................................................................... 99 Janja Kogovek, Liu Hong, Metka PetriŁ, Wu Wenqing 1.10. JIUXIANG ........................................................................................................................................ 113 Martin Knez, Janja Kogovek, Tadej Slabe 1.11. A STUDY ON RECENT KARST DENUDATION RATE OF KARST IN SHILIN, STONE FOREST ...................................................................................................... 122 Liu Hong 1.12. THE ANALYSIS RESEARCH ON SOIL EROSION CHARACTERS IN KARST MOUNTAINS AREA ENVIRONMENT XICHOU OF YUNNAN ................ 127 Chen Xiaoping kitkras1.p65 3.12.98,3:29 5 Black 6 1 South China Karst I 2. KARST STUDIES IN W GUIZHOU INTRODUCTION .......................................................................................................................... 137 Zhang Shouyue 2.1. THE KARST PLATEAU OF EAST YUNNAN AND WEST GUIZHOU ............................ 139 Zhang Shouyue 2.2. THE KARST ENVIRONMENT AND CAVES. RESOURCES OF LIUPANSHUI ............ 144 Shi Mengxiong & Zhang Shouyue 2.3. HYDROCHEMICAL PROPERTIES OF KARST WATER IN LIUPANSHUI .................. 158 Jin Yuzhang 2.4. SPELEOLOGICAL EXPLORATION AT TIANSHENGQIAO - NATURAL BRIDGE, SHUI CHENG ......................................................................................... 161 Gabrovek Franci, Andrej Mihevc, Bojan OtoniŁar & Nadja Zupan Hajna 2.5. KARSTOLOGICAL RESEARCH OF THE CAVE BY XINGCHANG VILLAGE ............. 170 Gabrovek Franci, Andrej Mihevc, Bojan OtoniŁar & Nadja Zupan Hajna 2.6. LITHOLOGIC CHARACTERISTICS OF YEZHONG PLATEAU ...................................... 175 Bojan OtoniŁar 2.7. SOME GEOMORPHOLOGIC OBSERVATIONS OF THE CONE KARST RELIEF IN WEST GUIZHOU ..................................................................................................................... 187 Andrej Mihevc 2.8. EFFECTS OF GEOLOGICAL STRUCTURAL ELEMENTS ON GENESIS OF CONE KARST IN NORTHWEST GUIZHOU ................................................................. 198 Nadja Zupan Hajna 2.9. CLASTIC SEDIMENTS FROM KARST OF SOUTHEAST YUNNAN AND NORTHWEST GUIZHOU ................................................................................................ 213 Nadja Zupan Hajna 2.10. LAND USE IN MOUNTAINOUS KARST AREAS ................................................................. 224 Andrej Mihevc 2.11. CONCLUSIONS ............................................................................................................................. 239 Zhang Shouyue, Andrej Mihevc, Bojan OtoniŁar kitkras1.p65 3.12.98,3:29 6 Black 7 1 Members of the Karst Research Institute ZRC SAZU, Postojna, and members of the Yunnan Institute of Geography and Institute of Geology of the Chinese Academy of Sci- ences gathered the results of karstological researches of south Chinese karst in two projects adopted by an agreement on scientific and technological cooperation between the Gov- ernment of the Republic of Slovenia and the Republic of China. The projects Karst Envi- ronmental Protection and Exploitation of Cave Resources and Study of Stone Forest Gen- esis, Function and Structures of the Underground Karst Aquifers in Lunan, Yunnan Prov- ince were going on from 1995 to 1997. They were made feasible by the Slovene and Chi- nese Ministry of Science and Technology and supported by Yunnan Provincial Science and Technology Commission, Administration of Stone Forest, and The Ninth Township Scenic Spots and Historical Sites Administrative Bureau, Yiliang County. The researches were carried out near Liupanshui, the western part of Guizhou, in karst between the mountains in Guizhou and Yunnan Plateau, in the area of Lunan stone forests and in cone-karst at Xichou, Yunnan. The edition of this book was enabled by Research Fund of Scientific Research Centre SAZU and Ministry of Science and Technology of the Republic of Slovenia. INTRODUCTION Geographical position of Yunnan and Guizhou kitkras1.p65 3.12.98,3:29 7 Black 9 1 South China Karst I Karst Studies of Yunnan 1 kitkras1.p65 3.12.98,3:30 9 Black 11 1 General introduction The Yunnan province is situated in the S of the Qinghai-Tibetan high plateau, with 2109 to 2915N latitude, 9739 to 10612 E longitude (Figs. 1.1.1., 1.1.2., 1.1.3., 1.1.4., 1.1.5.). It is 910 km long and 884 km wide territory of 394,000 km 2 . The Tropic of Can- cer passes across the Yunnan province. Topographically NW part has high eleva- tions. The highest peak of the Meili Snow mountain range is 6740 m above sea level and is located on the border of Yunnan and Tibet. Towards E, SE and SW, the relief is 1 Huang Chuxing, Liu Hong Karst of Yunnan 1.1. KARST OF YUNNAN Huang Chuxing, Liu Hong Fig. 1.1.1. The situation of studied area in Yunnan province kitkras1.p65 3.12.98,3:31 11 Black 12 1 lowering gradually, the lowest point is the joint place of the Nanxi river and the Red river with 76.4 m elevation in the Honghe county. The height difference between the highest and the lowest point is 6663.6 m. Generally, the whole Yunnan can be di- vided into 6 levels. Among them there are three main levels: 1600-1900 m in the N central part, 1200-1400 m in the S central part and 500-900 m in the S. The high pla- teau and mountains are predominately landforms that occupy 94% of the total area. According to the variant of lithological characters and geological structures, E Yunnan can be divided into three parts. (1) E Yunnan karst plateau: is composed by gen- tly undulated karst landforms which devel- oped on the Paleozoic and Mesozoic car- bonate rocks. Patterns of karst landforms are karst hills, Fengcong shallow depres- sions and Fenglin poljes. (2) NE Yunnan plateau: is the transit zone from the E Yunnan karst plateau to the Sichuan basin and the NW Guizhou karst plateau. Due to the Wumong mountain range and the Jinshajiang river its tributaries are deeply incised. The plateau surface landforms are very deeply expressed. (3) Central Yunnan red-bed plateau: is located in the W to the Kunming-Shipin county, the outcrop forma- tions are all in the Mesozoic red-beds, landforms are gently undulated and domi- nated by the down-shape plateau and intermountainous basins. The climate types are different in the Yunnan province. Influenced by SW monsoon and SE monsoon, the Tibet high plateau and complicated landforms, mainly parts of the Yunnan province, belong to tropic and subtropic high-land monsoon climates. They are characterized by: dry season and wet season, annual temperature difference is small, but daily changes are high; the rain- ing season occurs in summer. By the alti- tude and elevation increasing, from S to N there are 7 climate zones: N tropics, S sub- tropics, middle subtropics, N subtropics, S temperate, middle temperate and N temper- ate zones. The average annual precipitation of the whole province is about 1000 mm. The annual amount of precipitation is around 600 mm to 800 mm in the NW Yunnan, and some of them can occur as snow. In the S tropic and S tropic areas the annual precipitation can reach over 1600 mm. From May to October each year there is a raining season. From November to next April there is a dry season. There is about 80% to 85% of precipitation that occur in the raining season. There are a lot of rivers and lakes in the Yunnan province, which belong to the Yiluowadijiang river, Nujiang river, Lang- chang-jiang river, Golden river, Yuanjiang river and Nanpanjiang river systems. The strikes of the river are controlled by geo- logical structures and mountain ranges. The average river fall ratios are 1.25-3.74. For the influence of the monsoon climate, most of the river water quantities have the character of a seasonal change evidently. Meanwhile, the Yunnan province is also one of the five lakes distribution areas of China. There are 37 lakes with water areas over 1 1 Huang Chuxing, Liu Hong Karst of Yunnan Fig. 1.1.2. Group of Slovene and Chinese researchers. (Photo M. Knez) kitkras1.p65 3.12.98,3:31 12 Black 13 1 1 Huang Chuxing, Liu Hong Karst of Yunnan Fig. 1.1.3. Typical karst landscape in Xichou. (Photo M. Knez) Fig. 1.1.4. A great part of karst territory is picturesque agriculturally cultivated. (Photo M. Knez) km 2 . Most important are the Dianchi lake, Erhai lake, Fuxianhu lake, Chenghai lake and Luguhu. Those big lakes mostly belong to tectonic lakes. Their arrangement strikes coincide with the geological structure line strike, from N to S. The soil types also vary in Yunnan, red soil is the dominate soil type, and it can be kitkras1.p65 3.12.98,3:32 13 Black 14 1 found in almost the whole Yunnan. The soil vertical zoning is very clear. From the bot- tom of mountains to the top the soil usu- ally appears as the subsequently brick red soil, bright red soil, mountainous red soil (or yellow soil), red-brown soil, yellow- brown soil, brown soil, mountainous podzol, and desert soil. The distances of the varied soil types are very short, somewhere only some hundred meters. The undulate landforms and different climate conditions make the advantages of the developing varied karst geomorphology and caves. Large river systems and lakes have also formed the local karst solution base-level that controlled the karst landforms evaluation and development. Geological setting Lithology It is observed that karst in Yunnan is developed in Carboniferous, Permian and Upper Tertiary carbonate rocks. Ren Meier (1983) found that there were Carboniferous dolomite (CaO 33.2%, MgO 15%) and Upper Permian Maokou group limestone (CaO 54.7%, MgO 0.5%) out- cropped in the NE Yunnan, but the dolomite rocks were strongly karstified, the depres- sions, stone-teeth and dolines were strongly developed in them. But on the Maokou lime- stone they were not developed well. The reason is that the dolomite rock structure is middle-coarse, the particle diameter is 0.5-2 mm, as well as influenced by the ore body heat liquid recrystallisation, its porosity is high. Normally their biodetritic limestone and oolitic limestone have a high porosity and a good water permeability. Structure The structure has an obvious effect on the karst development in Yunnan. It has par- ticularly controlled the pattern of Yunnan karst landforms. Structurally, the E district is appropriate to the Yangtzi peneplatform and the southern China platform. For a long time the earth crust is relatively stable, and the thickness of sedimentary strata is very big. From the Upper Proterozoic to the Quaternary strata all are distributive in the 1 Huang Chuxing, Liu Hong Karst of Yunnan Fig. 1.1.5. One of few real karst poljes. (Photo T. Slabe) kitkras1.p65 3.12.98,3:32 14 Black 15 1 Yangtzi peneplatform. Their thickness range from 2000 m to 4000 m occupies 20%-45% of the total strata thickness. In the S China platform, a great part of the Upper Palaeozoic strata is built of carbonate rocks. The Triassic limestone is widespread. The Summating carbonate strata are 4000-7000 m thick, account 30-60% of the total strata thickness. Distributive carbonate rock areas of these two fields account about 50% of the total land area (Ren Meier, 1983). The western Yunnan belongs structur- ally to the geosyncline belt. The thickness of carbonate rocks is 1000 m 5000 m that account 10-25% of the total strata thickness. Zhongdian and Lijiang of the NW Yunnan belong to the Indosinides folding zone, the carbonate rocks thickness can reach to 4000 m - 7000 m that accounts 20-45% of the total stratum thickness. In the W the karst developed on a more concentrated district as Baoshan, Lijiang, Dali, Lingchang and Xichuangbanna area. In the E Yunnan platform zone and W geosyncline area the karst development and distribution are obviously different. The E carbonate rocks distribution area of the platform belt is broad, lithologic variety is small and dip is gentle. Karst landforms are well developed. For the W geosyncline belt the carbonate rocks distribution area is nar- row and the surface karst is not developed. It is characterized by low hills and corro- sive denuded mountains. There is no typi- cal karst morphology developed. At the inner sub-zone field the structural control action is still more evident. The structure line has controlled the whole karst landforms pattern. The most typical example is the Xichou county, Wenshan. The neotectonic movement is quite strong and has a great impact on the gen- esis and evolution of the geomorphology in Yunnan. The neotectonic uplift movement raised the lower Yunnan peneplain to the elevation level of the present plateau. On the W side rivers cut in the surface and formed the gorges that separated high mountains. A strong fault movement hap- pened and reactivated some old faults, while the structure uplifted. Under the structure block-faulted movements a series of block mountains and fault basins were formed. The Dongchuan Xiaojiang fault is an active large fault, there are high block mountains on both sides of the fault and the fault itself appears as a valley or fault basin. Intensive and frequent earthquakes are another appearance of the neotectonic movement. In Yunnan there are 1-2 earth- quakes a year of over 6 grades. Karst geomorphology in Yunnan The karst geomorphology is limited in solution rocks, limestone, dolomite, gyp- sum, anhydrite and rock salt distribution areas. The carbonate karst surface prevails in Yunnan. Areas with the gypsum or fossil salt karst are smaller. China is one of the karst most developed country in the world, the carbonate rocks outcrop area is over 1,250,000 km 2 (China karst research group, 1979). Three prov- inces Yunnan, Guizhou and Guangxi are intensive and typical karst areas where the karst occupies 320,000 km 2 of the total area, i.e. 28.9% of the total area, and the karst area in Yunnan includes 110,900 km 2 . Considering the scale and extent of the developed karst the Yunnan province can be placed along the 102 E longitude line and the Honghe river. The karst landforms density distributes in E parts. But in the W area the karst areas are scattered and un- typical. The Yunnan province has different karst landform types, from S to N, tropic karst, temperate karst and alpine frigid karst are presented disciplinary. The Lunan Shilin (stone forest), Yiliang Jiuxiang Cave system, Gangnan Babao Fenglin-basin scenery, and the Zhongdian Baishuitai Adarce platform which is more than 3000 m above the sea level, are representatives of the Yunnan karst. Karst forms Fengcong-Depression is a composition of the conterminal base karst cone and depressions. The depression 1 Huang Chuxing, Liu Hong Karst of Yunnan kitkras1.p65 3.12.98,3:32 15 Black 16 1 area is normally smaller than 0.5 square kilometers and has clay draping and a sinkhole at its bottom. The normal relative altitude of Fengcong is smaller than 100 meters. It is the most developed karst form in Yunnan. Construed by the depression depth it can be divided into the Fengcong shallow depression and the Fengcong deep depression. From watershed to the river valley the Fengcong depression forms changes from the Fengcong shallow de- pression to the Fengcong deep depression. The depth of the depression increases from 50 m to 150 m or more (Song & Liu, 1992). Fengcong Valley is composed by karst cones and valleys among them. It mainly distributes at the watershed area where a large spring or an underground river comes out of the karst plateau on both sides of rivers. It widely distributes in the E and SE Yunnan. For in- stance, it is well developed along the Chouyang river in Xinjie of Xichou and Malipo counties. Hillock Depression is composed by Conterminous base hummock alternated by depressions. Com- pared with the Fengcong depression, here the karst develops normally weakly. Topo- graphically there is an undulation of the hill state, and the relative high difference is less than 50 m. Terra rossa developed well and was widely distributed in the watershed areas of the E and SW Yunnan. Fenglin Basin and Valley are composed by karst peaks which are base free on the valley or basin plain. Their relative height difference is 200 m and less. It is mainly distributive at the SE Louping county, Pingyuanjie basin, Gangnans Babao basin and Luxi areas of the E Yunnan and the SE Yunnan. They are also common in Menglian, Mengding and Bingma of Bao- shan of the W Yunnan. Residual Hill and Paniform is a later period phase of the karst devel- opment. It is formed by the Fenglin evolves toward karst hummock by further abrasion, and the basin evolves to paniform. It is drap- ing of red brick clay that has funnels, dish- like depressions and the blocked sinkholes distribution. There are also some stone- teeth developed nearby residual hills and isolated peaks. It is mainly distributed in the Shilin period abrasive paniform in Lunan- Luliang-Louping and Zhongheying-Ping- yuanjie areas. Yunnan karst development stages After the carbonate rocks were lifted up the karst phenomena developed wide- spread. Taking into account the Yanshan movement which has had a deep impact on the Yunnan geologic and landform evolu- tion as a boundary, the karst can be divided into four stages: Pre-Cambrian ancient karst stage, Old Palaeozoic ancient karst stage, Later Palaeozoic ancient karst stage, and Old Mesozoic ancient karst stage (China Karst Research, 1979). In Cenozoic the karst can be divided into different stages: plateau stage, stone forest stage and canyon stage. Plateau Stage Its genesis and development is con- cerned with the whole landform evolution history of Yunnan. The end of the Mesozoic Yanshan movement has made the Yunnan present day fundamental outline of land- forms. Palaeogene Himalaya movements occur in a large area with up-lifts and a fault activity. Before the Miocene movements Yunnan was relatively quiet in the tectonic sense. In that period almost the whole of Yunnan belonged to the tropical climate field, and the rivers activity was weak, the Huang Chuxing, Liu Hong Karst of Yunnan kitkras1.p65 3.12.98,3:32 16 Black 17 1 uniform denudation of landforms and shal- low karstification prevailed. Stone Forest Stage The second period of the Himalaya tec- tonic activity happened during Miocene to Pliocene by uplifting and fault movement. During the Pliocene mesophase Mengzi, Datunhai, Caoba, Jijie and Dazhuang were most probably linked together and became a lake. In the Upper Tertiary lake face sedi- mentation of the Ciying group the coal beds are represented. In lifting the ascended zone formed a wide range of the Fenglin depression, Fenglin basin, stone forest and large-scale poljes typical karst senility land- scapes. Topographic undulation is small, with the height difference of 100-300 m. This karst landform plane is called the stone forest period landform. Some also call it »lake basin stage« (Yunnan agricul- tural division Office, 1987). In Quaternary neotec-tonic lifts up ascended and block break motion made the denuding abrasion face of the stone forest stage distributed at different elevations. The Nanpanjiang river upstream ample watershed area is the best preserved karst denudation plane in China. There are shallow depressions, dolines and funnels, as well as residual karst lakes, the Yuehe lake, JiJianhe, and the stone forest in Lunan for instance. The S debasement of elevation from the N in the NE Yunnan is 2100 m, and in Kunming- Shizong 1800 1900 m. In Lunan and Yiliang it is distributed at the height of 1700 1800 m. Canyon Stage This stage was developed in Quaternary. In the E the Nanpanjiang river and the Yuanjiang river formed canyons and river valleys which developed therein multiple level terraces and nick points. The vertical karstification is reinforced in downward river valley districts of the nick point where the underground water level descends and the aeration zone thickness increases. Dolines and the Fengcong deep depression morphology were developed by that. The depth of shafts can reach up to several hun- dred meters. In Niupeng Yanzidong in Mengzi for instance, affected by the Lushihe river incision, the cave reaches 267 m of depth. The groundwater yielded deep runoffs and developed multilayered caves and underground river systems. In the downstream far from nick points there is another new landforms type devel- oped. In the upstream above the river nick point or watershed area the retrogressive erosion of rivers has not yet strongly af- fected districts. The stone forest stage landforms face is gradually disintegrated or broken up. As a consequence it has yielded the phenomena of karst landforms from the river valley to the watershed area an ordi- nal appearance young stage - mature stage - old stage. Landform features of this stage the karst has not formed yet. They are in a developing phase. To sum up, the present karst landforms of Yunnan is formed mainly on account of the stone forest stage that recreates through a later stage, especially reactivating karst during the canyon stage. Huang Chuxing, Liu Hong Karst of Yunnan kitkras1.p65 3.12.98,3:32 17 Black 18 1 1 H. Chuxing, M. Knez, L. Hong, T. Slabe, S. ebela The Lunan Stone Forests A stone forest (Fig. 1.2.1.) is a unique form of pinnacle karst (Ford & Williams 1989, 337). The pinnacles that are criss- crossed with fissures and cracks are com- posed of rock pillars (Song Lin Hua 1986; HabiŁ 1980, 109) and stone teeth (Song Lin Hua 1986; Song Lin Hua & Liu Hong 1992). Stone teeth are smaller protuberances less than five meters high; tall teeth are higher than three meaters, and short teeth are lower than one meter (Song Lin Hua & Liu Hong 1992). They are divided according to their shape into canine teeth, molar teeth, 1.2. THE LUNAN STONE FORESTS Huang Chuxing, Martin Knez, Liu Hong, Tadej Slabe, Stanka ebela and ridge stone teeth (Song Lin Hua & Liu Hong 1992). The pillars range from five to fifty meters tall and are of various forms. Along with former and current factors of formation, their shape is determined prima- rily by their composition, stratification, and the way the rock has been crushed. In uni- form rock, the pillars are usually broader at the bottom, if they have not been narrowed by the subcutaneous dissolving of carbon- ate rock, of course, and become narrower especially at the top. Mushroom-shaped pil- lars are formed when the lower beds are Fig. 1.2.1. Shilin stone forest. A stone forest is a unique form of pinnacle karst. (Photo M. Knez) kitkras1.p65 3.12.98,3:32 18 Black 19 1 1 H. Chuxing, M. Knez, L. Hong, T. Slabe, S. ebela The Lunan Stone Forests thinner, densely fissured, and when the rock is very porous or made of dolomite; in short, they decay faster. A stone forest de- velops in thickly-stratified, relatively pure limestone whose layers are inclined no more than 15 and crisscrossed with a net- work of vertical fissures. A stone forest does not occur on distinctly crushed rock. Song Lin Hua (1986, 6,7,8) distinguishes three types of stone forests according to their position. In lowlands and valleys, large forests with intervening sinkholes and hol- lows are formed. Underground waters flow below them, they are periodically flooded, or water flows through them. Forests on the tops of hills are lower (10-30 m), their pil- lars grow from a common foundation, and the sediment that covered them was thin. Forests on the slopes of hills are an inter- mediate form between these two types. In most cases, a stone forest is described as a form of covered or subjacent karst (Chen Zhi Ping et al. 1983) or cryptokarst (Maire et al. 1991; Sweeting 1995, 125). The carbonate rocks on which pinnacles occur were covered by thick sediment which de- cisively influenced the development and form of the stone forest. Depending on the sediment, a forest can be denuded, covered, or buried. Hantoon (1997, 311) describes stone forests as an epikarst form. Large stone forests are a characteristic form of polytropical and subtropical cli- mate conditions (Song Lin Hua 1986, 3,5). The stone forests in Lunan have been relatively well and comprehensively stud- ied, and some of the more distinct rock forms on pillars have been described. These descriptions found in the literature are in- cluded in the chapters on individual rock forms. We have not found, however, a com- prehensive description of the rock relief, but the obstacle might be the Chinese lan- guage. We devoted the studies to the forms of pillars in different types of lowland stone forests and specifically to their rock relief that reveals the factors of their formation and often of their development as well. We supplemented and also modified previous explanations of the origin of some rock forms, but, of course, the study must be con- tinued and individual hypotheses verified. The rock relief described is characteris- tic of larger stone forests that were origi- nally covered with sediment and soil, then stripped and transformed by rainwater. The rock relief of smaller pinnacles that were originally formed under the ground was formed in a similar manner. The Lunan stone forests The Lunan stone forests are among the most remarkable in the world. The Shilin Central Forest spreads over eighty hectares, while larger and smaller stone forests are distributed over an area of 350 km 2 (Chen Zhi Ping et al. 1983; Zhang Faming et. al. 1997a). The tourist sections of the Lunan stone forests are visited by more than a mil- lion people every year. They are a unique and integral natural and cultural landscape where the Sani minority lives, now partly from tourism. The geological structure of rock in the wider area of Lunnan is revealed as a series of interchanging ridges and depressions (tectonic troughs) in a north-south direc- tion. It is generally well-known that the east- ern and central parts of the region were fully elevated during the Cenozoic and now comprise vast, high plateaux. It is mostly Early Palaeozoic and Triassic carbonate rock which extends above all over east Yunnan. At the same time we find indi- vidual smaller carbonate areas in some parts of west Yunnan (Zongdian, Dali and Licang) (Sweeting 1995). The rock in some parts of the Lunnan area is of a very monotonous structure, al- though in some places a variegated altera- tion of diverse types of limestone and dolo- mite can be found in the geological profiles. This is reflected in the process of selective carbonate corrosion and erosion, and thus in the shape and morphological appearance of particular stone columns, larger blocks of rock and the landscape relief. The main characteristics of carbonate rock are: a high concentration of carbon- ates, great thickness, and the great age of the rock which forms the vast carbonate complexes. They are mostly of the platform kitkras1.p65 3.12.98,3:32 19 Black 20 1 1 H. Chuxing, M. Knez, L. Hong, T. Slabe, S. ebela The Lunan Stone Forests type and are distinguished by a high level of purity, regularity in the distribution of various carbonate types, and uniform thick- ness. In addition, one of the characteristics of this rock is that, due to its age, it felt the strong effects of diagenetic processes. These characteristics are directly reflected in the hydrological response of the bedrock, as well as in the general development of the karst. In the Lunnan area the basic features of carbonates appear at a number of levels. One of the more significant features is un- doubtedly its Early Permian age. Typical stone forests generally develop in ridge biomicrite and biosparite deposited on the gentle sloping of shallow-water coasts. This carbonate rock, additionally characterised by thick layers and a uniform chemical com- position, is thought to be best for the for- mation of high stone columns. The particu- lar stratigraphic and lithologic features which were found in the geological profiles additionally contribute to the formation of remarkable shapes. The preliminary analy- ses carried out this year assisted in solving several presuppositions (Knez 1997c). In various climatic and geological con- ditions, three different types of karst have formed: • a tropical rain forest karst in the south; • a tectonic depression (graben) karst; • a high plateau karst with »stone forests«. Tropical rain forest karst The vastest peripheral tropical area in China stretches out across Xishuangbann province. Two karst areas stand out: Mengla province, an area covering around 500 km 2 , and the territory along the Lancang river (450 km 2 ). In Mengla province, Permian and Middle Carboniferous grey massive limestone, biolithic limestone, pseudo- oolitic limestone, bioclastic limestone and Triassic dolomite limestone prevail. The carbonate layer deposit is over 2000 m thick. Under the influence of the humid tropical climate, the limestone underwent intensive karst processes during the Quar- ternary. The characteristics of the karst landscape along Lancang river is reflected in numerous depressions and blind valleys where stone teeth, as well as individual stone columns, are quite frequent. Tectonic depression (graben) karst Karst in tectonic depressions (Song Lin Hua & Liu Hong 1992) is a very widespread occurrence in the wider Lunnan area, where there are at least 28 divided parts, none of which is less than 100 km 2 . The larg- est is the so-called Kunming basin (named after Kunming, the capital of Yunnan prov- ince), exceeding an area of 1100 km 2 and with a water-collecting hinterland of over 3000 km 2 . The loose rock covering in Kunming basin is approximately 1000m. High plateau karst with »stone forests« »Stone forests« indicate a specific type of karst landscape with characteristic groups of standing limestone columns reaching a height of over 50 m. Limestone columns usu- ally stand on a gently wavy base. A comprehensive and diverse system of water courses (Zhang Faming et al. 1997a, 5) developed under the forests. The form and height of the pillars in the forest are characteristic of the individual type of rock and their topographical position (Zhang Faming et al. 1997b, 73). Mangin (1997, 106) believes that the epikarst of the stone forest reaches a depth of 100 meters. The Lunan forests originated largely through the dissolving of the rock underground by water from the soil which contains biotic CO 2 and sediment. The wa- ter enlarges the fissures and separates rocks. Under the acidic soil, wide and deep cracks occur between the pillars as well as deep channels on their walls (Yuan Daoxian 1997). The uncovered carbonate rock is re- shaped by rainwater. First, teeth appear and from them, a forest (Song Lin Hua 1986, 13). I studied the rock relief in three selected, dissimilar Lunan forests. Originally, there was limestone, already karstifying (Yu Jinbao, Yang Baoguo 1997; kitkras1.p65 3.12.98,3:32 20 Black 21 1 1 H. Chuxing, M. Knez, L. Hong, T. Slabe, S. ebela The Lunan Stone Forests Song Linhua, Wang Fuchang 1997, 433) and covered by Permian basalt and tuff which influenced the shape of the forest, and rock that in some places underwent metamor- phism (Song Linhua, Li Yuhui 1997; Ford et al. 1996, 34). Water percolated through the basalt and tuff and began the develop- ment of the underground karst. In the Mesozoic, part of the limestone was de- nuded (Song Linhua, Wang Fuchang 1997, 433). In the Oligocene and Miocene, stone blocks rose and dropped, and in lower ar- eas the karst relief was reshaped by erosion (Yu Jinbiao, Yang Baoguo 1997). In the Eocene, the Lunan graben collapsed, depos- iting thick layers of lake sediment (Chen Zhi Ping et al. 1983; Zhang Faming et al. 1997a, 433). In the tropical climate, thick layers of laterite soil appeared on the sediment (Sweeting 1995, 124; Ford et al. 1997, 112). In the Pliocene, the current stone forest began to develop (Yu Jinbiao, Yang Baoguo 1997, 66). In the Quaternary, a large pro- portion of the sediment was dislodged but remained in the fissures. With the development of the under- ground water courses, pillars began to de- velop from the teeth (Fig. 1.2.2.) (Zhang Faming et al. 1997a). The level of the un- derground water played an important role in the development of the forest (Ford et al. 1997,114). The oscillating underground water widened the fissures (Yuan Daoxuian 1991). The Shilin (central) stone forest (Fig. 1.2.3.) is situated between 1625 and 1875 meters above sea level. The forest is located in a lowland with underground waters that lie close to the surface and rise up to ten meters after heavy rain. The majority (70- 80%) of the annual 936.5 mm of precipita- tion falls between June and October (Chen Fig. 1.2.2. Shilin stone forest. With the devel- opment of the underground water courses, pillars began to develop from the teeth. (Photo T. Slabe) Fig. 1.2.3. The Shilin Central Forest is situated between 1625 and 1875 meters above sea level. (Photo T. Slabe) kitkras1.p65 3.12.98,3:32 21 Black 22 1 1 H. Chuxing, M. Knez, L. Hong, T. Slabe, S. ebela The Lunan Stone Forests Zhi Ping et al. 1983). The mean tempera- ture is 16.3C and varies from -2C to 39C. The pillars are tallest in the central part of the lowland where the surface waters run into the underground. There is more sedi- ment on the margins of the stone forest (Sweeting 1995, 125). HabiŁ (1980, 110) defines it as shallow karst. In the lower part of the stone forest (Fig. 1.2.4.), water also runs on the surface. The Shilin (central) stone forest devel- oped on thickly layered and vertically fis- sured Lower Permian carbonates of the Maokou period composed of limestone and dolomite in the lower part. In the middle of the pillars are also concretions of chert. The limestone is sparry and bioclastic and in some places slightly dolomitized (Swe- eting 1995, 125). The limestone layers are mostly five meters thick and inclined by 5. The lithological characteristics were studied by Knez (1997c), and the charac- teristics of tectonic fracturing by ebela (1996). The pillars in the central part of the for- est in the lowland are as tall as 35 meters. In the middle area, they mostly stand close together; between them are cracks mostly one to five meters wide, while on surround- ing larger surface areas, they also stand in- dividually (Fig. 1.2.5.). They are therefore the remains of carbonate rock between fis- sures and are shaped accordingly. Their cross sections are square and triangular, as well as oblong and narrow. The dense fis- suring of the rock resulted in smaller pillar cross sections. The pillars whose lower parts are composed of thinner and fissured beds are mushroom-shaped and as a rule have pointed tops starting at the same level. Those pillars that were subcutaneous below ground have somewhat more squarish tops The pillars are also dissected along bedding planes and along longer-lasting levels of sediment and soil. Notches along bedding planes are often jagged, a reflection of the stylolite formation of the rock. Pointed and blade-like pillars with sharp tops and ridges dominate. Through laboratory tests on the shaping of pinnacles in gypsum, Dzulinski, Gil, and Rudnicki (1988, 8) determined that pillars acquire a pyramidal shape when the Fig. 1.2.4. Shilin stone forest. In the lower part of the stone forest, water also runs on the surface. (Photo M. Knez) kitkras1.p65 3.12.98,3:33 22 Black 23 1 1 H. Chuxing, M. Knez, L. Hong, T. Slabe, S. ebela The Lunan Stone Forests cracks between them widen. The shape of pillars on evenly composed carbonate rock should be pyramidal and sharp: the purer the limestone, the sharper the shape of the pillar. On relatively evenly composed car- bonate rock, the action of rainwater hol- lowed distinct rock forms across the sub- cutaneous rock relief. The Naigu stone forest lies twenty kilometers east of the Shilin (central) stone forest and is also an important tourist attrac- tion. The pillars, 20 to 30 meters tall, are tower-like with mostly square cross sections and with many short, pointed tops. The pil- lars are often linked in rows between dis- tinct faults. Between larger rock masses are individual, sometimes narrow pillars (Fig. 1.2.6.). The cracks between the pillars have been eroded to various widths, from a few centimeters to ten meters and more. The tops of pillars (Fig. 1.2.7.) united into ex- tensive towers are at a uniform level. Many pillars, particularly individual pillars, are mushroom-like. The edges of the pillars are often curved, only the ridges between chan- nels are sharp. Along the bedding planes, they are indented by distinct cracks. Their rock relief is less distinct and unique be- cause of the uneven composition of the rock, especially the smaller rock shapes, and the rock surface is rough. That the forest developed on Qixia rock is reflected also in its form and rock relief. The lower sections of the pillars are com- posed of thicker beds of limestone and their forms are more rounded, medium-thick beds of limestone lie above them and the pillars are narrower, and the upper sections of the pillars are composed of dolomite limestone (Ford et al. 1997, 115). In most cases, the form of the subcuta- neous stone teeth does not reflect the dif- ferent composition of the rock. They are either rounded or pointed like the subcu- taneous teeth on other rock. Only the larg- est differences in the composition of the rock stand out. Below the forest is a Baiyun tourist cave (Fig. 1.2.8.) where it is possible to read many periods of their development from the rock relief. Water currents flowed through the flooded passages with a speed of 0.5 m/s Fig. 1.2.5. Shilin stone forest. Between pillars are cracks mostly one to five meters wide, while on surrounding larger surface areas, they also stand individually. (Photo M. Knez) kitkras1.p65 3.12.98,3:34 23 Black 24 1 1 H. Chuxing, M. Knez, L. Hong, T. Slabe, S. ebela The Lunan Stone Forests Fig. 1.2.7. Naigu stone forest. The tops of pillars united into extensive towers are at a uniform level. (Photo M. Knez) Fig. 1.2.6. Shilin stone forest. Between larger rock masses are individual, sometimes narrow pillars. (Photo T. Slabe) kitkras1.p65 3.12.98,3:34 24 Black 25 1 (Kranjc 1989). This is confirmed by the ba- salt gravel in the cave and in front of it and by smaller scallops that do not have very distinct forms. They were covered by the fine-grained sediment which filled the cave. On the ceiling are large above-sediment ceil- ing channels (Slabe 1995, 61) that are sev- eral meters in diameter as well as above- sediment anastomoses. The extensive above-sediment anastomoses, whose sur- face measures several square meters, there- fore have several levels (Slabe 1995). The smallest channels are three centimeters in diameter and the largest fifty centimeters, while those with five to ten centimeter di- ameters dominate. The above-sediment ceil- ing forms indicate the long-term reshaping of the cave by water flowing across the fine- grained fill. The cave in the heart of the park is part of the cavernous karst underground below the stone forest and indicates peri- ods of rapid outflow of water from the sur- face and the carrying away of the sediment that covered the limestone. There were rela- tively long periods when the cave was filled with fine-grained sediment and the surface above it was flooded. This indicates the in- termittent growth of the stone forest. Examples of distinctive, mostly mush- room-like, 30-40 meter high pillars are found in the Lao Hei Gin stone forest (Fig. 1.2.9.), twenty kilometers northeast of the Shilin Central Forest. The tallest pillars are in the lowest part of the forest, from where the largest quantity of sediment was washed away. The stone pillars can be di- vided into larger rock masses that are criss- crossed by thinner fissures and have many smaller pointed tops and individual pillars separated by extensive patches of sediment. The individual pillars have the form of square towers or are mushroom-like. They are frequently composed of several blocks, the remains of layers of rock between bed- ding planes and fissures. The central part of the pillars quickly crumbles into fine debris and disintegrates. The rock disinte- grates mostly in grains which makes the rock surface rounded; it is only angular under the thin flakes. The rock is porous, and the central sections of the pillars are interwoven with numerous tubes that are from one centimeter to one meter and more in diameter. The rainwater shapes the rock relief on the tops of the pillars and the more voluminous base, that is, on the sections where the rock is most resistant to decay. The rock relief is therefore the reflection of the composition and tiny fissuring of the stone which was first shaped below the ground for a long period and then reshaped by rainwater. Sinkholes often occur between pillars and in them, caves. Thirty to fifty meters below the surface, water currents in the nearby caves flow with a discharge to 3 m 3 , and exceptionally up to 4-6 m 3 . As a result, in this forest the water can flow off the sur- face due to the developed underground water network, taking with it the sediment and soil from the limestone and dolomite. Fig. 1.2.8. Naigu stone forest. Below the forest is a Baiyun tourist cave where it is possible to read many periods of their development from the rock relief. (Photo T. Slabe) H. Chuxing, M. Knez, L. Hong, T. Slabe, S. ebela The Lunan Stone Forests kitkras1.p65 3.12.98,3:34 25 Black 26 1 H. Chuxing, M. Knez, L. Hong, T. Slabe, S. ebela The Lunan Stone Forests In August 1996 we carried out speleo- morphological researches of some horizon- tal caves near Lunan Stone Forest. We vis- ited 3 horizontal caves, 2 of them were mapped for the first time, the map of Baiyun cave (Naigu Stone Forest) existed before. The Naigu stone forest lies north from the Shilin (Lunan) Stone Forest and is tour- ist arranged. Naigu means »black« in the Sani language. An area of 7.38 km 2 has been opened to tourists in 1986. It consists of two parts (E and W part) with a path about 6 km long winding through the high and steep rock pinnacles. There are magnificent topography, primitive simplicity, unusually shaped rock formations, jadeite-colored lake water, spectacular caves enchant tour- ists. By a tourist visit of the Naigu Stone For- est the visit to the horizontal Baiyun cave is included. The cave is 500 m long and opened for public visits from 1989. General strike of the cave is N-S. The water flow strike was also from N to S. It is a typical phreatic passage which is today in vadose conditions. In the area of the Naigu Stone Forest we find 7 caves. Beside others these are: Zhiyun cave, Dieyun Rock cave, Jibailong cave. None of them is longer than 1 km. On the SE edge of the Naigu Stone For- est the Xin Shi Dong cave was measured (Fig. 1.2.10.) on 22 July 1996. Before our visit the cave was closed with a big rock for the protection of the flowstone inside against vandalism. The measurements of the cave were done by dr. Stanka ebela, mag. Metka PetriŁ and Mr. Huang. Studies of per- colated waters were done by mag. Janja Kogovek. Coordinates of the entrance are 24 54 05 N and 103 21 30 E, with the elevation of the entrance 1785 m. General strike of the cave is N-S. Inside the cave the water flow is not active any more, but be- cause of precipitation the water can be found in pools. The water level can rise oc- casionally (also to 2 m) what can be con- cluded from the level of red sediments on cave walls. Fig. 1.2.9. Examples of distinctive, mostly mushroom-like, 30-40 meter high pillars are found in the Lao Hei Gin stone forest. (Photo M. Knez) kitkras1.p65 3.12.98,3:34 26 Black 27 1 H. Chuxing, M. Knez, L. Hong, T. Slabe, S. ebela The Lunan Stone Forests The measured cave length is 175.5 m, the depth is 6.5 m. From the low entrance 0.6 x 1 m we reach the entrance collapse chamber. The cave is rich in flowstone. There are many columns which divide the wide passage (up to 12 m) into more parts. The thickness of the ceiling above the cave is not big, not thicker than 10 m, the ceil- ing in the cave is low, not higher than 3 m. Xin Shi Dong was developed in the Permian limestone, which strike and dip in the N part of the cave is 310/5. At all the cave ceilings we can observe planes similar to tectonic structures which are in fact plains caused by sediments. The cave was filled up with sediments which were later removed. In the SE part the cave ceiling low- ers to less than 0.9 m and becomes impass- able. Between numbers 10 and 9 we find massive gours showing strike of the water flow from N towards S, NW-SE. On the wider area of the water tracing experiment N from the Lunan Stone For- est the number 7 represents the Guan Yin Dong cave (Fig. 1.2.11.). In fact it is a spring cave in the E edge for which we would need a boat or divers. This cave is intersected by a bigger collapse doline (Fig. 1.2.12.), which is continuing into a ponor cave on the W side. This cave is ac- cessible and was measured on 20 July 1996 by dr. Stanka ebela, Liu Hong, Chen Xiaoping, mag. Metka PetriŁ. Within the speleological studies there were also in- volved dr. Tadej Slabe, dr. Knez Martin and mag. Janja Kogovek. Fig. 1.2.10. Map of cave Xin Shi Dong (ground plan, longitudinal and cross sections); a-strike and dip of bedding planes, b-point of cave measurements, c-collapse blocks, d-flowstone, e-lake. kitkras1.p65 3.12.98,3:34 27 Black 28 1 H. Chuxing, M. Knez, L. Hong, T. Slabe, S. ebela The Lunan Stone Forests The Guan Yin Dong cave is 239.2 m long and 5.7 m high. It is still an active ponor cave which was measured in the scale of 1:500. The water flow strike is towards S with more cave passages curves. There are 2 principal passage strikes, NW-SE and NE- SW. Between the points 7 and 6 there is a collapse doline, 15 m wide, with the mate- Fig. 1.2.12. Collapse doline and entrance into Guan Yin Dong cave. (Photo S.ebela) Fig. 1.2.11. Map of cave Guan Yin Dong (ground plan, longitudinal and cross sections); a-point of cave measurements, b-direction of water flow, c-strike and dip of bedding planes, d-collapse doline, e-water flow. kitkras1.p65 3.12.98,3:34 28 Black 29 1 H. Chuxing, M. Knez, L. Hong, T. Slabe, S. ebela The Lunan Stone Forests rial fallen into the cave. That is the shaft with 10 m of depth. The cave is developed in the Permian limestone with strike and dip 120/10 at the entrance. The thickness of bedding is 1 m. In the entrance the principal fissures are 90/90 and 10/80-90. Strike and dip of bed- ding in the spring cave on the E side of the collapse doline is 200/5-10. Directly through the middle of the collapse doline there is an anticline axis in the general strike N-S. The development of the collapse doline, that is a collapse of the former cave ceiling, is connected with folding deforma- tions and formation of the anticline and fis- sures. The entrance of Guan Yin Dong is 23.5 m wide and 13-15 m high. At the entrance there are remains of an old mill. On 20 July 1996 we measured the discharge of the sinking stream into the cave which was 30 l/s. The passage in the entrance of the cave is not higher than 8 m. The water flow sink- ing at the point 11 appears again at the point 9. At the point 3 from the NW side passage a smaller water flow joins the prin- cipal passage. The point 1 is the final siphon. Between the points 12 and 9 there are mas- sive gours which are oriented in strikes to- wards NE and SW. The underground water level is in ac- cordance with horizontal caves which were explored in the depth of 30 m. There are cave systems which are speleologically not explored yet, but results of the tracing ex- periment test have shown that there are pretty good direct connections. The thin roof above cave passages which can be from 10-15 m high is in many places collapsed, what caused that horizontal caves can be accessible by shafts (15-60 m deep) or from dolines or collapse dolines. General strike of the water flow is towards S. Horizontal caves survived the phreatic phase and the period of fillings in with sediments and re- placement of sediments. Common are mas- sive gours and flowstones which overlay sediments. A small dip of bedding planes 5- 10 0 corresponds to the orientation of the horizontal passage, but meandering of the passage inside bedding is determined by structural elements. kitkras1.p65 3.12.98,3:34 29 Black 30 1 General characteristics of carbonate rock in the Lunan stone forests The most characteristic of the Chinese stone forests is undoubtedly the one situ- ated in the direct vicinity of the city of Lunan (Lunan Shilin). The stone columns there have distinct sharp peaks. The col- umns are generally higher than 10 m. Stone forests, in general as well as in the Lunan area, potentially develop in very 1.3. LITHOLOGIC PROPERTIES OF THE THREE LUNAN STONE FORESTS (SHILIN, NAIGU AND LAO HEI GIN) Martin Knez thick-layered and chemically-pure lime- stone. Some data indicates that Lunan stone forest developed in carbonate strata to over 30 m thick (Chen et al 1985; HabiŁ 1980; Mihevc 1994; Song 1986; Song & Liu 1992; Sweeting 1995; Waltham 1984). The thick- ness of layers in other stone forests in south- ern China is much smaller (only around 2 m). Lunan stone forest developed in Early Permian limestone (Maokou formation). Figure 1.3.1. Shilin stone forest. Lunan stone forest is located on a wavy karst plateau 1720- 2000 m above sea level. (Photo M. Knez) Martin Knez Lithologic Properties of the three Lunan Stone ... kitkras1.p65 3.12.98,3:34 30 Black 31 1 1 Martin Knez Lithologic Properties of the three Lunan Stone ... Figure 1.3.2. Shilin stone forest. The peaks of some columns over 30 m high are very sharp due to homogenous and compact rock. (Photo M. Knez) The rock was very leveled; despite this, the sloping of the layers did not exceed 10 on average. In some stone forests the average slope of the layers is up to 20. It has been found that if the slope of the strata exceeds 15, large stone columns cannot develop (Song 1986). Varying tectonic pressures caused the development of numerous fis- sures which form a dense network (cf. ebela 1996; cf. Kogovek et al 1997). The research was not only based on sam- pling rock from individual stone columns, as it was paid most attention to the contact of various rocks in the geological column. In some cases this contact was revealed by the stronger corrosion of a particular part of the profile, which was morphologically expressed in the rock. Finding contact be- tween lithologically diverse rocks was of- ten based on continuous sampling. We discovered that in selective corro- sion, various levels of porosity play a spe- cial role in Lunan stone forest. In some places it was macroscopically noticeable that individual areas of the geological pro- file, i.e. the stone columns, essentially un- derwent more potent corrosion and ero- sion effects. Research carried out at the microscopic level, although not yet com- plete, confirms this fact. The lithostratigraphic conditions in Shilin stone forest The carbonate rock in Shilin stone for- est (Fig. 1.3.1., 1.3.2.), which has an area of 11 km 2 (Salomon 1997) does not change through the geological profile from the structural and textural points of view, with the exception of some short sections. All the samples studied by microscope revealed that the 250-million-year-old rock had been altered a great deal by diagenetic processes. The fossil remains are mostly unrecogniz- able, even though they are not tectonically damaged. The dip of the strata, which is mostly around 5 (Fig. 1.3.3.) and rarely more than 10, indicates minor regional movement. At the same time, the results of microscopic observations indicate that the dip of the strata today most likely reveals only a relatively short phase of the inclin- ing of the terrain in a non-vertical direction and/or that the blocks remained undam- aged between the not-very-densely-located fractures. Irrespective of this, we find nu- merous tiny, calcite-filled fissures in which no noticeable shearing movements have oc- curred. Calcite veins can be difficult to lo- cate macroscopically due to the purity and crystalline nature of the bedrock carbonate. The regionally vast gentle anticlinal eleva- tion of the rock happened during a number of phases and periods. Other researchers also point out that there had been a number deformations of the Permian rock (cf. Yuan 1991). Geological column is divided into 4 se- quences: A, B, C and D. Total thickness of geological profile (stone column) under study is 37 m. kitkras1.p65 3.12.98,3:34 31 Black 32 1 1 Martin Knez Lithologic Properties of the three Lunan Stone ... Sequence A Sequence A is 7 m thick. The lower part of the sequence, i.e. the base of the stone column, is of biopel- micrite to biopelmicrosparite limestone of the wackstone type (samples 1251, 1252, 1253, 1254, 1255, 1256). Fragments of various bioclastics prevail among the allochemes: uniserial, biserial and fusulinid foraminifers, shellfish, snails and other unidentifiable organisms. Espe- cially characteristic of Shilin limestone are separate whole and crushed fusulinid foraminifers. In some places we noticed evidence of bioturbation. The numerous pellets are mostly no larger than 0.09 mm; most frequently their average size is 0.045 mm. Larger snails measure up to 7 mm in diameter. Smaller plasticlastics most likely occur among intraclastics. Of the types of porosity the most com- mon are moldic and shelter porosity. There are no calcite veins, although frequent sec- ondary porosity is noticed. Fossil remains comprise 20% of the rock, pellets and pelletoids up to 10%, and fusulinid foraminifers (whole and crushed) less than 1%. Drusy mosaic calcite predominates in the directly precipitated calcite (orthochemical component), fills the inside of whole and well-preserved large fossils, replaces shells and fills individual caves. The anhedral to subhedral calcite crystals are 0.09 mm to 0.7 mm large (on average 0.27 mm). The calcite forms a mostly ksenotopic structure. Chips of large fossils (e.g. fusulinid foraminifers) are more damaged on the bottom side; signs of endolithisation are noticeable. Hollows in micritic intraclasts are fre- quently found to be filled with large mo- saic crystal calcite. Filled hollows usually point to gravitation cement. The geopetal filling of fenestrae with internal sediment underneath and large crystal sparite above and outside the clastics is also characteristic of the section of the geological profile. Figure 1.3.3. Shilin stone forest. The dip of the layers in Lunan stone forest is less than 5. (Photo M. Knez) kitkras1.p65 3.12.98,3:34 32 Black 33 1 1 Martin Knez Lithologic Properties of the three Lunan Stone ... Due to the position of the large crystal calcite in the fenestrae, there is no doubt that the strata are in a normal position. One metre above ground, i.e. one metre above the present point of the exposed stone column, we notice pelbiomicro- sparite to pelbiosparite limestone of the grainstone type (sample 1257). Among the allochemical components, pellets and pelletoids are by far the most frequent, comprising over 90%. The first have a diameter of 0.09 mm, the latter from 0.09 mm to 0.18 mm, exceptionally up to 0.23 mm. There were no noticeable intra- clasts in this part of the geological profile. The biogenetic component is represented mostly by fragments of various fossil re- mains. Larger pieces of thick shells are ex- ceptionally well preserved. The orthochemical component (sparite) is among the allochemes in the form of granular cement. The size of calcite crystals is between 0.045 mm and 0.32 mm, the av- erage size being around 0.09 mm. The lime- stone is of a very homogenous and compact nature; no calcite veins were noticed. Three metres above the base of the pro- file the lithologic features of the limestone change noticeably. It passes from a pels- parite to a biointramicrite limestone of the wackstone to packstone type (sample 1258). Bioclastics prevail in the slightly recry- stallised rock, taking up 35 to 40% of the volume. They are mostly approximately foraminifers (0.09 mm) and fragments of various fossils. Plasticlasts with a grain di- ameter of 0.36 mm to 1.35 mm appear only exceptionally. Grain direction in the rock is very dis- tinct. The longer axis is parallel to the strati- fication. Sample 1259 was taken 5 m above the profile base. The limestone is of the bio- micrite type without apparent fossil mate- rial. Exceptionally small foraminifers ap- pear. Sparite fields of granular calcite are stratified in levels parallel to the stratifica- tion. There are no calcite veins. Just below the top of the sequence we find pelsparite limestone (sample 1960). Pellets are the dominant allochemical com- ponent in the rock, taking up around 90% of the rock volume. Granular sparite crys- tals, around 0.09 mm in size on average, form cement. Some fenestrae in the very washed-out pelsparite have a diameter of around 0.9 mm, and the size of the mosaic sparite crystals is up to 0.45 mm. Sequence B Sequence B (divided from sequence A by a bedding-plane) forms a whole and, from the point of view of lithology, is much more evenly built. It is necessary to stress the fact that the area bordering on sequence A, i.e. the section above and below the bed- ding-plane that divides the sequences, is of limestone with the same features. The thick- ness of the sequence is 13 m. At the beginning of the sequence we find, as we did at the top of sequence A, pelsparite limestone (sample 1961). The two sequences differ mainly in the level that the cement is washed-out. Pellets are also the dominant allochemical component in the rock, taking up around 90% of the rock volume. Granular sparite builds the cement, which is less washed-out than the sparite in sample 1260. Individual calcite veins (between 0.09 mm and 0.23 mm thick, Fig. 1.3.4.) are present in the sample; they are filled with two generations of sparite crystals. In the middle of the sequence a belt of chert nodules, a few metres wide, is visible (samples 1263, 1264, 1273) (Fig. 1.3.5.). All the nodules have a characteristic zone struc- ture. On the outside, dark and light belts can be distinguished, the latter being wider. The dark and narrower zone contains a major part of the carbonate component. This is most likely caused by the silification of the carbonate component. Numerous carbon- ate intrusions occur in the zones of silifi- cated rock. The upper part of the sequence (sam- ple 1262) is comprised of slightly washed- out pelbiointramicrite of the wackstone type. The rock is quite diagenetically al- tered, so many primary forms and features are impossible to define clearly. kitkras1.p65 3.12.98,3:35 33 Black 34 1 1 Martin Knez Lithologic Properties of the three Lunan Stone ... Figure 1.3.4. Shilin stone forest. Individual calcite veins are present in the sample; they are filled with two generations of sparite crystals. (Photo M. Knez) Figure 1.3.5. Shilin stone forest. In the middle of the sequence a belt of chert nodules, a few metres wide, is visible. (Photo M. Knez) kitkras1.p65 3.12.98,3:36 34 Black 35 1 1 Martin Knez Lithologic Properties of the three Lunan Stone ... Among the allochemes, pellets and pelletoids prevail; there are fewer frag- ments of various bioclastics: uniserial, foraminifers, shells and other unidentifiable organisms. In some places on the bioclastics we notice signs of bioturbation. The numer- ous pellets are mostly no larger than 0.09 mm; most of them have a diameter of 0.045 mm. Smaller plasticlastics probably occur among the intraclastics. Of the orthochemical components, drusy mosaic calcite prevails, fills the inside of whole and well-preserved large fossils, replaces shells and fills individual caves and fissures. Anhedral to subhedral calcite crys- tals are between 0.23 mm and 1.8 mm in size. Here, calcite builds a mostly kseno- topic structure. Sequence C Sequence C (divided from sequence B by a bedding-plane, Fig. 1.3.6., 1.3.7.) is mo- notonous from the lithologic point of view and is not noticeably different to the rock and sequence below it. It is 13 m thick. Figure 1.3.7. Shilin stone forest. Detail from Figure 1.3.6. (Photo M. Knez) Figure 1.3.6. Shilin stone forest. Sequence C is monotonous from the lithologic point of view and is not noticeably different to the rock and sequence below it. (Photo M. Knez) kitkras1.p65 3.12.98,3:36 35 Black 36 1 1 Martin Knez Lithologic Properties of the three Lunan Stone ... The rock in the lower part of the se- quence has the same features as the rock observed in the upper section of sequence B (samples 1265, 1266, 1271). The most apparent difference is only in the ortho- chemical component, where micrite calcite grains were generally found to be slighter. In the upper section of the sequence we noticed individual non-transparent miner- als up to 0.23 mm in size, and individual euhedral calcite grains. Sequence D The thickness of sequence D varies from 3 to 5 m due to its conical peaks, which are most exposed to atmospheric influences (Fig. 1.3.8.). The carbonate sedimentation has not changed noticeably in this part of the geo- logical column. The top of the sequence, i.e. of the stone column, is of biopelmicrite limestone of the wackstone type (samples 1267, 1268, 1269, 1270). Among the allochemes, fragments of various bioclastics, which are difficult to identify due to moderate recrystallisation, prevail: various foraminifers and fusulinid foraminifers, shells, snails, etc. In some places on the bioclastics we notice signs of bioturbation. Pellets are mostly no larger than 0.14 mm; most of them have a diam- eter of 0.09 mm. Of the orthochemical components, drusy mosaic calcite prevails, filling the in- side of whole and well-preserved large fos- sils, replacing shells and filling individual caves. In the samples from the upper sequence of the geological column we find somewhat more calcite veins. Their thickness ranges Figure 1.3.8. Shilin stone forest. The thickness of sequence D varies from 3 to 5 m due to its conical peaks, which are most exposed to atmospheric influences. (Photo M. Knez) Figure 1.3.9. Naigu stone forest. C haracteristic relief of rock surface. (Photo M. Knez) kitkras1.p65 3.12.98,3:36 36 Black 37 1 1 Martin Knez Lithologic Properties of the three Lunan Stone ... from 0.09 mm to 0.7 mm. They are mostly filled with one generation of sparite crys- tals. Calcite veins are not evenly filled in all places, and allow for the observation of interparticle and fracture porosity. The lithostratigraphic conditions in Naigu stone forest Naigu stone forest covers an area of 8 km 2 (Salomon 1997). It is composed of rock from the Qixia formation, which alters a few times through the geological profile (Fig. 1.3.9.). Changes in colour, stratifica- tion, porosity and intrusions are noticeable at several points. The base of the lowest ex- posed part of the Qixia stone forest (where lies Baiyun karst cave, Fig. 1.3.10.) is com- posed of light-brown-to orange massive and homogenous carbonate. Rock that is less resistant to corrosion and erosion follows in the profile; it makes up a leaner portion of the column beneath an otherwise wider and more resistant upper part. Geological column divided into 6 se- quences: A, B, C, D, E and F. The total thick- ness of the geological profile (stone col- umn) under study is 51 m. Sequence A Sequence A is 2 m thick. The base of the stone column is formed from a very recrystallised pelbiomicrite to pelbiomicrosparite of the grainstone type (sample 1274). Although the rock is called pelbio- micrite, a well-preserved fossil inventory is extremely rare. The rock underwent dolo- mitisation and, on the outside, has a grainy and simultaneously speckled appearance. The speckles in the rock, with a diameter of between 1.3 mm and 12 mm (about 4 mm on average), are in fact non-dolomitised or less dolomitised fields in a dolomitised foundation. In some places in the nearly 100%- dolomitised foundation we find idio- Figure 1.3.10. Naigu stone forest. Baiyun cave below Naigu stone forest. Varicoloured lighting is characteristic of Chinese caves. (Photo M. Knez) kitkras1.p65 3.12.98,3:36 37 Black 38 1 1 morphic euhedral grains of dolomite, en- closed in micrite and/or microsparite. In general, the structure of the foundation, as well as of the speckles, is ksenotopic and slightly hipidiotopic (the latter only in some places). Sequence B Sequence B is 2 m thick. Over sequence A is a pelmicrite limestone of the mudstone type (sample 1275). The rock is of an extremely homogenous struc- ture. No larger concentrations of individual intrusions are noticeable. The rock does not have calcite veins or secondary porosity. Pellets are evenly distributed in the micrite foundation. They frequently give the impression of being parallel with their longer axis. The average diameter of the allocheme pellet grains is 0.07 mm. Beside the pellets, less numerous fields of sparite crystals appear in the micrite foundation; most of them are no larger than 0.14 mm. Sequence C Sequence C is 5 m thick. Above se- quence B is pelmicrite limestone of the mudstone type (sample 1275). Overlying sequence is a micrite to sparite carbonate of the mudstone to grainstone type (samples N1, N2, N3, N4,). The rock is extremely hard and not weath- ered in its interior even though bands are macroscopically clearly visible. It has been found that the foundation of the rock (that is the proportionally larger part) is nearly pure calcite, while the bands are dolomite. In the middle of the sequence a belt of chert nodules, a few metres wide, is visible (Fig. 1.3.11., 1.3.12.). Martin Knez Lithologic Properties of the three Lunan Stone ... Figure 1.3.11. Naigu stone forest. Various lithologic characteristics of the rock are reflected in the morphology of stone columns. (Photo M. Knez) Figure 1.3.12. Naigu stone forest. Detail from figure 1.3.11. (Photo M. Knez) kitkras1.p65 3.12.98,3:36 38 Black 39 1 Sequence D Sequence D is 5 m thick. The primary limestone is heavily altered by the process of diagenesis by means of a microscope we were able to observe sub- hedral to euhedral grains of dolomite in the rock which form the hipidiotopic to idio- topic structure (samples 1276, 1277). We can call the rock dolosparite of the grain- stone type as there are no fossil or pellet interclasts. The dolomite grain size ranges form 0.09 mm to 0.9 mm, on average 0.23 mm. The dolomite grains are generally ex- tremely pure and translucent. There are re- mainders of calcite among the dolomite grains, but not exceeding 15% of the rock. Fillings of fine fissures are also of calcite. Sequence E Sequence E is 5 to 10 m thick, it was 7 m thick at the location where the sample was taken. The rock is a biopelmicrite to bio- pelmikrosparite of a mudstone to wack- stone type (samples 1278, N5, N7) and con- tains numerous cherts, with the longer axes measuring between a few centimetres to over 10 cm, in singular horizons. Growth of crystals has been very widespread in the carbonate rock, so the fossil remains are barely distinguishable. In some of the larger ones (0.7 mm) we can observe nicely rep- resented shelter porosity. In the rock in the vertical direction we find a number of contacts of very thick micrite mass and biosparite to biomikro- sparite mass in which we found numerous tiny fossil remains, these are not definable due to extensive crystal growth. Sequence F Sequence F is 5m thick. Sequence F does not differ essentially from sequence E. In some points it is thickly meshed with calcite veins with a thickness of 0.02 mm to 0.045 (samples 1297, 1280, N8, N9). We found numerous contacts of calcite and dolomite rock in the vertical di- rection. The dolomite parts (dolomicro- Martin Knez Lithologic Properties of the three Lunan Stone ... Figure 1.3.13. Laoheigin stone forest. Rock in the lower sections of the stone columns is more porous than the upper sections, which is reflected in the morphological image. (Photo M. Knez) kitkras1.p65 3.12.98,3:36 39 Black 40 1 sparite to dolosparite) of the wackstone to grainstone type are built of subhedral to euhedral dolomite grains, which form a hipidiotopic to idiotopic structure. Sequence G Sequence G has a thickness of 20 to 30 m, it was around 25 m thick at the location where the sample was taken. This is the thickest more or less homog- enous rock mass in which dolomite and cal- cite areas are intertwined at irregular con- tacts and positions (samples 1281, N10, N11, N12, N13). On the exterior they form a characteristically rough surface (T. Slabe, chapter 1.5.; cf. Slabe 1995), while on the interior the situation is very complex and complicated due to extremely strong diagenesis activity and shattered rock. In general the rock is a biomicrosparite to biosparite or biodolomicrosparite to biodolosparite. Of the allocheme compo- nents, bioclastics are very poorly preserved, there are signs of it being worm-eaten, and signs in some places of moldic porosity. The lithostratigraphic conditions in Lao Hei Gin stone forest Lao Hei Gin stone forest (Fig. 1.3.13., 1.3.14.) is located around 20 km north of Shilin. Individual stone columns and large blocks modified by corrosion and erosion are spread across an area of only 2 km 2 . The columns are morphologically similar to the columns in Naigu stone forest (Fig. 1.3.15., 1.3.16.). The geological column is divided into 4 sequences: A, B, C and D. The total thick- ness of the observed geological profile (stone column) is 26 m. Sequence A Sequence A is 7 m thick. The lower part of the stone column is composed of a heavily recrystallised dolosparite to dolomicrosparite of the grainstone type (samples L1, L2). The pri- mary limestone is heavily altered by dia- genesis under the microscope we could observe subhedral to euhedral grains of dolomite in the rock, these compose the hipidiotopic to idiotopic structure. The dolomite grains are from 0.14 mm to 0.9 mm large, on average 0.27 mm. The dolo- mite grains are mostly of a light-brown col- our in translucent light, although singular larger grains are extremely pure and almost completely translucent. In a few percent of the dolomite crystals, autogenic over- growth is clearly visible. There is 6% calcite substance in the rock. Secondary porosity is considerable. Sequence B Sequence B is 8 m thick. Sequence B does not differ considerably from sequence A. Above sequence A is also Martin Knez Lithologic Properties of the three Lunan Stone ... Figure 1.3.14. Laoheigin stone forest. Rapidly decaying stone columns. (Photo M. Knez) kitkras1.p65 3.12.98,3:36 40 Black 41 1 a heavily recrystallised dolosparite to dolomicrosparite of the grainstone type (samples L3, L4, L5). The dolomite (dolomicrosparite to dolosparite) of the grainstone type is built of subhedral to euhedral dolomite grains, which compose a hipidiotopic to idiotopic structure. The essential difference between the rocks from both sequences is that the rock from sequence B is secondarily porous to a considerably greater extent. The dolo- mite crystals are on average smaller than the crystals in sequence A (0.23 mm) even approximately 0.09 mm in the upper part of the sequence - and at the same time less pure. Sequence C Sequence C is 5 m thick. The rock is limestone, only about 10% of the rock is dolomite crystals (sample L7). In the vertical direction the rock immedi- ately passes into biopelintramicrite to biopelintramicrosparite. The fossil remains are generally not well preserved, only in Martin Knez Lithologic Properties of the three Lunan Stone ... Figure 1.3.16. Laoheigin stone forest. Some cave sections are seen in the lower part of the columns. (Photo M. Knez) Figure 1.3.15. Laoheigin stone forest. Stone columns stand in a number of groups on a slightly anticlinal structure. (Photo M. Knez) kitkras1.p65 3.12.98,3:36 41 Black 42 1 some parts are there better preserved sin- gular foraminifers and thick-shelled snails. There is no noticeable secondary porosity. Sequence D Sequence D is 6 m thick. Sequence D is composed of rock which is practically identical to that of sequence A and represents the top of the stone col- umn. The rock is heavily recrystallised dolosparite to dolomicrosparite of the grainstone type (samples L8, L9, L10). The primary limestone is heavily altered by diagenesis we can observe subhedral to euhedral dolomite grains composing a hipidiotopic to idiotopic structure. The grains of dolomite are 0.09 mm to 0.23 mm large, on average approximately 0.18 mm. The dolomite grains are mostly of a light- brown colour in translucent light, although singular larger grains are extremely pure and almost completely translucent. Among the more important differences we can observe more frequent rounded and unfilled fissures from 0.09 mm to 0.18 mm in width, and a considerably lower dolomite content at the top of the column on account of calcite. Conclusions The opinions on the effect of lithology on the morphology of the karst, and on in- dividual stone columns and stone blocks, are interesting. Some karst researchers (Zhang 1997) maintain that there is no in- fluence from the carbonate composition and rock structure on the development and form of the karst and its formations. The author also points out that stone forests may develop in dolomite as well as limestone, with or without chert intrusions, and that they can develop on carbonate rock of di- verse structural and genetic types. Others (Salomon 1997) are of the opinion that the particular features of the lithostratigraphy (cf. Knez 1994, 1995, 1996, 1997a, 1997b) are an essential factor in development and formation, and present a morphological image of karst formations, through the whole process from stone teeth to stone columns. There was not found any literature con- cerning detailed microscopic research into samples from geological profiles of the stone forests under examination. Despite this, one of the studies mentions that some microscope sections have been prepared from samples from Shilin stone forest. How- ever, it was impossible to find out if the eventual results of the microscope analyses are obtainable. In the parts of the geologi- cal profile which it was possible to exam- ine in the direct vicinity of Shilin, it was found that the microscopic analyses did not show larger biostratigraphic changes in the rock. Lithologic anomalies were of greater significance in all three stone forests. Even though the results of calcimetric analyses are frequently contained in re- search results, detailed research involving microscopic and calcimetric analyses of contact in lithologically diverse rock, where selective erosion is often clear, was not found. To illustrate, there are outlined the results of calcimetric analyses of two car- bonates (Knez 1997c). That sample A and sample B are, in fact, two different rocks in the profile (there was no vertical distance between them, they have been in contact) could be noticed only because of their slightly different colour. With regard to macroscopic and micro- scopic analyses of rock from three stone forests in the vicinity of Lunan, it was found that the type of rock was clearly reflected in the selective corrosion and erosion of Martin Knez Lithologic Properties of the three Lunan Stone ... Table 1.3.1. Example of two carbonate rocks; intensive corrosion occurred in contact. *All values in %, except in the last column. SAMPLE CaO* MgO Calcite Dolomite Total carbonate CaCO 3 MgCO 3 Ca0/MgO A 51.76 3.23 84.38 14.75 99.13 92.38 6.75 16.02 B 32.41 20.16 7.82 92.21 100.00 57.87 42.13 1.61 kitkras1.p65 3.12.98,3:36 42 Black 43 1 Martin Knez Lithologic Properties of the three Lunan Stone ... carbonate, and thus in the form and mor- phological appearance of individual stone columns and larger stone blocks. The calcimetric analysis (Table 1.3.1) was performed by Mateja Zadel at the Karst Research Institute ZRC SAZU. kitkras1.p65 3.12.98,3:36 43 Black 44 1 In the sense of geological investigations of Stone Forest turistical part of Shilin was structural-lithological mapped. In July 1996 measurements of strike and dip directions of bedding planes as also principal tectonic zones was accomplished. Final aim was ba- sic structural-geological map with statisticaly determined frequency of directions of tec- tonic zones and bedding planes. 1.4. STRUCTURAL CHARACTERISTICS OF SHILIN STONE FOREST Stanka ebela Stanka ebela Structural Characteristics of Shilin Stone Forest Geological data »Stone forests« belong to karst plateaus in eastern Yunnan (Sweeting 1995). Devonian and Permian limestones are covered by Eocene (and possibly Miocene) lake muds and clays and a deep lateritic soil cover. The Lunan Stone Forest consists of Permian limestones and dolomites. Accord- Fig. 1.4.1. The Lunan Stone Forest-bedding planes are gently deformed to syncline (Photo S. ebela) kitkras1.p65 3.12.98,3:38 44 Black 45 1 1 Stanka ebela Structural Characteristics of Shilin Stone Forest Fig. 1.4.2. Stone pillars in Lunan Stone forest (Photo S. ebela) ing to geological map (1:50.000) the beds in park gently dip from 2 0 to 8 0 , in average for 5 0 and strike towards west. In the base the Devonian beds are overthrusted to the Permian beds. In limestone open synclines (Fig. 1.4.1.) and anticlines with dips from 3 0 to 17 0 may be seen. Where the limestones are thick- bedded and strongly jointed, rock columns up to 30 m high can be formed (Sweeting 1995). The stone pillars (Fig. 1.4.2.) are devel- oped in the Lower Permian Maokou (354 m thick) and the Qixia (100 m thick) lime- stones. Both of these limestones are very uniform in composition and are thickly bed- ded. The Maokou is a platform, sparitic and bioclastic limestone (Song Linhua 1986). It is slightly dolomitized in places. The Qixia is a massive reef limestone and also dolomitic. Widely spaced fractures are critical to the formation of the stone forest. If the car- bonate rock mass has been tectonicaly stressed and has developed sets of oblique fractures, the structural weakness of the rock makes it difficult for tall pinnacles to remain stable. The main sets of rock frac- tures are close to vertical (Zhang Shouyue 1997). The outlines of the pillars are related to the directions of the jointing, the main joints at the Lunan Stone Forest being N20 0 W, N50 0 W and N50 0 E. The N20 0 W joints are pre-Cenozoic and are filled with calcareous tufa, but the other joints are Cenozoic in age and are open vertical in- tersecting fissures which cut the sub- horizontal Maokou limestones (Sweeting 1995). Lunan Stone Forest lies east from Jiu- Xian-Shiyakou fault which makes part of Xiaojiang folded belt. Geological elements of the fault are 70-80/60. Local water table in the Lunan area are Sword Peak Pond, Lotus Flower Pond and Stone Forest Lake (Fig. 1.4.3.). The superfi- cial and underground waters drain into Bajiang, towards S and SW. The under- ground water flows in epiphreatic chan- nels. kitkras1.p65 3.12.98,3:38 45 Black 46 1 1 Stanka ebela Structural Characteristics of Shilin Stone Forest Water level in Sword Peak Pond and Lo- tus Flower Pond may increase for 10 m. The situation of the Lunan Stone Forest is determined by movements along Jiu-Xian fault zone. These movements controlled the deposit of Eocene rocks and permitted gen- tle covering of Permian limestones. More than 500 m thick layer of red loam was de- posited in the Lunan area. Modern stage of karst development in- cludes the late Miocene to the Holocene, some 7 to 4 million years ago. This stage corresponds to intensive uplifting of the Tibet plateau and records the appearance of deep valleys (Miocene - Holocene). The uplifting of the Earth crust in the Tertiary and the Quaternary played an important role at karst development in southern and western China. It caused the changes in karst water level. Continental crust of China is intensively affected by neotectonic move- ments (the modern Himalayas displace- ments) which is important for development and various types of karst in China (Zhang Zhigan 1980). Ford et al. (1997) describe that karst developed in Lower Permian carbonates was buried by terrestrially erupted Upper Permian tuffs and basalt lavas (Emeishan Formation). Remnant basalt patches are up to 50 m thick in Shilin area but 600 m thick near Kunming. Measurement of fissures in the Lunan Stone Forest I measured dip and strike of fissures in the area of the Lunan Stone Forest. Lime- stone pavement is formed along the most frequent trendings of fissures. In a rose graph (Fig. 1.4.4. and Table 1.4.1.) is shown the frequency of the fis- sure directions. Out of total number of fis- sures (N=202) the direction 315-330 0 (NW- SE) is the most common (20.79%). The sec- ond place (15.34%) occupies the direction 45-60 0 (NE-SW) and the third one (14.35%) the direction 285-300 0 (NW-SE). Poorly are represented the directions N- S although regionally important geological structure lines are of this direction. This fact implies the idea that the area of stone for- est lies among stronger faults; a block is Fig. 1.4.3. One of ponds in Lunan Stone Forest (Photo S. ebela) kitkras1.p65 3.12.98,3:38 46 Black 47 1 Stanka ebela Structural Characteristics of Shilin Stone Forest broken in two main jointings, NW-SE and NE-SW. When the pathways in the park were made the fissures among the pinnacles were used and thus the main tourist ways are concordant to fissures in a limestone (Fig. 1.4.5.). It is typical of the fissures to dip very steeply, almost vertically (80-90 0 ). According to Sweeting (1995) the main joints are N20 0 W which differs for at least 10 0 from mine measured and analysed data. In the book Karst of China (1991) Yuan Daoxian summarizes the researches done by Zhang Shouyue (1983) who was the au- thor of a linear structures map in the Lunan Stone Forest. According to this map the most frequent tectonic structures are N50 0 W. In a central part of the Lunan Stone For- est (Fig. 1.4.6.) the most expressed dip di- rection is 50 o and transverse dip direction 140 0 , 160 0 and 180 0 . In eastern part of stone forest the dip direction 80 0 (N10 0 W) pre- vails. West from touristically displayed path- ways in the Lunan Stone Forest there is a thicker layer of red loam deposited in a val- Fig. 1.4.4. Rose graph of jointings in the Lunan Stone Forest (N=202) Fig. 1.4.5. The fault zone in the Lunan Stone Forest (Photo S. ebela) kitkras1.p65 3.12.98,3:38 47 Black 48 1 1 Stanka ebela Structural Characteristics of Shilin Stone Forest Fig. 1.4.6. Structural-geological sketch of the Lunan Stone Forest. 1 - lake or pond, 2-touristic pathways, 3-strike and dip of strata, 4-strike and dip of structural zones kitkras1.p65 3.12.98,3:38 48 Black 49 1 Stanka ebela Structural Characteristics of Shilin Stone Forest ley, oriented to 110 0 (N10 0 E). South from the Stone Forest Lake and along the south- ern touristic pathway the direction of the jointing is 0-20 0 (E-W, N80 0 W, N70 0 W). During field mapping I could not de- termine bigger displacements along some joints. It is fact that on the mapped area (Fig. 1.4.6.) there is not an uniform direction of joints intersecting all the others. Thus we perceive that directions NW-SE are inter- sected by directions NE-SW and vice versa. The relative age of the main joints in the Lunan Stone Forest thus cannot be deter- mined for sure. Measurement of layers in the Lunan Stone Forest I measured 52 dips and strikes of strata. The results are shown in structural-geologi- cal sketch (Fig. 1.4.6.), in Schmidt net (Fig. 1.4.7.) and in rose graph (Fig. 1.4.8.). The main direction of strike is NW and W (Fig. 1.4.7.). Due to small dipping of beds lithological column is accessible in a thickness of 200 m. In its lower part, accessible in the east- ern part of the Stone Forest and also in its central part through deep fissures it con- tains limestone with inliers of cherts jutting out of a limestone. The layers in upper part of the lithological column are the least sta- ble in case of earth-quakes. It is evidenced by numerous collapse blocks that had fallen into the fissures during the earth-quakes of the last decades. At least 21.2 % of limestone layers have direction N16-30 0 E (Fig. 1.4.8. and Table 1.4.2.) striking westwards for 5 to 20 0 , in average for 5 0 . Fig. 1.4.8. Rose graph of layers in the Lunan Stone Forest (N=52) Fig. 1.4.7. Schmidts net - the layers of lime- stone in the Lunan Stone Forest (N=52) kitkras1.p65 3.12.98,3:38 49 Black 50 1 In the southern part of the stone forest (Fig. 1.4.6.) the layers of limestone dip not only towards NW and W but also towards SW. As already Sweeting (1995) pointed out the structures in the limestones of the Lunan Stone Forest are open synclines and anticlines. The anticline ridge is the most obvious in S and SE part of the Stone Forest (Fig. 1.4.6.). Conclusions The stone pillars or pinnacles that form a stone forest developed below soil, the fis- sures widened and later some typical below sediment features developed. By measuring geological elements of strike and dip of fissures in the Lunan Stone Forest and by basic statistical data process- ing it was established that in the Lunan Stone Forest three main directions of fis- sures prevail. These are 315-330 0 (NW-SE), 45-60 0 (NE-SW) and 285-300 0 (NW-SE). As the main regional tectonic structures are directed N-S the area of the Lunan Stone Forest presents morphologically slightly el- evated terrain between two stronger fault systems inside which the limestones jointed in three main directions. The fis- sures that widened below the sediment cover are displayed as pinnacles of the stone forest since the sediment cover had been removed. The layers of Permian limestones strike towards NW and W dipping for 5 to 10 0 , they are gently folded into several smaller anticlines and synclines. To attain a more complex explanation of tectonic conditions it would be neces- sary to widen the researches over the bor- ders of touristic part of the Lunan Stone Forest. Table 1.4.2. Statistical evaluation of the direction of layers in Lunan Stone Forest. N=52 Table 1.4.1. Statistical evaluation of fissures trending in the Lunan Stone Forest (N=202) direction no. of measurements % position 1-15 0 0 0 12 16-30 0 5 2.47 11 31-45 0 8 3.96 9 46-60 0 31 15.3 2 61-75 0 22 10.9 4 76-90 0 17 8.4 6 271-285 0 8 3.96 9 286-300 0 29 14.4 3 301-315 0 19 9.4 5 316-330 0 42 20.8 1 331-345 0 10 4.95 8 346-0 0 11 5.44 7 direction no. of measurements % position 1-15 0 5 9.6 4 16-30 0 11 21.2 1 31-45 0 4 7.69 6 46-60 0 8 15.4 3 61-75 0 2 3.8 8 76-90 0 2 3.8 8 271-285 0 0 0 12 286-300 0 2 3.8 8 301-315 0 1 1.9 11 316-330 0 3 5.76 7 331-345 0 5 9.6 4 346-0 0 9 17.3 2 Stanka ebela Structural Characteristics of Shilin Stone Forest kitkras1.p65 3.12.98,3:39 50 Black 51 1 1 Tadej Slabe Rock Relief of Pillars in the Lunan Stone Forests Rock relief is often a significant reflec- tion of the conditions under which various factors and processes shape carbonate rock. The rock relief indicates the formation of the coat of the rock which composed of rock forms (Slabe 1995). The rock is shaped by one of the factors or exhibits traces of several different factors that wear away the rock either simultaneously or sequentially. The characteristics of the formation of the stone forests and partly their development as well are therefore reflected in the rock relief of pillars in the stone forests. On de- caying and non-homogenous rock, charac- teristic rock relief frequently does not ap- pear or is less distinct. The composition of the rock also dictates the roughness or smoothness of the rock surface. Many individual rock forms carved by rainwater as well as some subcutaneous forms have been described in detail and the research on them so far has been summa- rized in the books Karst Geomorphology and Hydrology (Ford & Williams 1989) and Karren Landforms (Ed. Forns & GinØs 1996), and more works are mentioned in 1.5. ROCK RELIEF OF PILLARS IN THE LUNAN STONE FORESTS Tadej Slabe the descriptions of individual rock relief. My intention was to supplement the list of rock forms on the pillars of the stone for- ests and expand the knowledge of the less studied rock forms, to add special features of the stone forests, and to describe the rock relief of the forests, defining it as traces of their development. During the classifica- tion of cave rock forms (Slabe 1995), I de- termined that it is more sensible and useful to combine them according to the factors and processes which shaped them and the surroundings in which they appeared and not just according to the characteristics of the forms. I therefore did the same in this work (see table below). In naming them, I frequently add the most important charac- teristic of their origin to the basic forms. Subcutaneous rock forms on the pillars of the stone forest The importance of subcutaneous dis- solving of carbonate rock in forming the Lunan stone forest has been stressed by al- Table 1.5.1. Rock forms that comprise the rock relief of pillars in the stone forests SUBCUTANEOUS ROCK FORMS Under sediment and soil Under thin layers of soli On the level of soil and vegetation subcutaneous tubes subcutaneous small subcutaneous small bells and half-bells small and large channels and large channels and large channels small and large recesses subcutaneous scallops subcutaneous small notches solution pans and large recesses SUBCUTANEOUS ROCK FORMS RESHAPED BY RAINWATER ROCK FORMS CARVED BY RAINWATER kitkras1.p65 3.12.98,3:39 51 Black 52 1 1 Tadej Slabe Rock Relief of Pillars in the Lunan Stone Forests most all of its researchers. Rock pillars are originally formed below the sediment and soil and then reshaped by rainwater. The majority of researchers also enumerate and briefly describe individual rock shapes formed below the ground. I have added the adjective »subcutaneous« to the majority of the characteristic rock forms, an expression very graphically applied to karst forms of this type by Gams (1971). Gams (1997, 324) also stresses the speed at which carbonate rock dissolves below the soil. I already de- scribed, named, and attempted to explain the formation of cave rock forms that oc- cur in contact with fine-grained sediment (Slabe 1995). In most cases, subcutaneous rock forms could be called epikarst forms because they are linked to the characteris- tic formation of stone forests in this part of a karst area. The importance of waterwhich be- comes rich in CO 2 as it percolates through the soilin shaping the rock under the soil is stressed although this influence is pre- sumed to decrease after two or three me- ters. However, I have observed that the in- fluence of water percolating along the con- tact point between rock and soil reaches deeper in individual places, a fact related to the degree of permeability. J. Kogovek (chapter 1.6.) established that water that has percolated through the soil and a cave ceiling has greater hardness than rainwater at the contact with the rock, which indi- cates the influence of the soil on the water. Hantoon (1997, 311) divided the perme- ability of epikarst into its permeability at the contact between sediment and rock, its permeability through rock, and finally its permeability through sediment containing clay, which should be low. According to Hantoon (1997, 313), the dissolving of car- bonate rock is most efficient below sedi- ment. Song Lin Hua (1986, 9) also brings up the importance of the recurrent corro- sion capability of the water where water that has percolated through the soil mixes with saturated water running along the junction between rock and soil. Large sub- cutaneous channels are therefore dissected by horizontal notches. Song Lin Hua also states (1986, 9) that the speed of the forma- tion of the forest in areas with organic ma- terial in the soil is ten times greater than those on the tops of the hills. Zhang Shouyue (1997, 79) determined that corro- sion notches and niches were formed un- der the sediment. According to the fre- quency of distinct turns in subcutaneous channels below soil and large horizontal subcutaneous notches, I conclude that the junction with the rock is often poorly per- meable and the corrosion is distinctly more effective at the level of the soil and under- neath it. Below the subcutaneous channels, which are wide in the upper part, and the horizontal notches, there are often smaller winding channels. Of course, the size of subcutaneous rock forms is also influenced by the quantity of sediment in the cracks between the pillars and the period of their formation. The largest channels occur when the level of the sediment lowers gradually but evenly. Rock forms whose origin is linked to the fine-grained sediment and soil that entirely or partially covered the pillars in the period of their formation, I divided (see table) into those that originate deeper under the ground, that is, completely subcutaneous rock forms, those that originate under a thinner layer of soil and vegetation, and those that originate at the surface of the soil and are composed and directly shaped by rainwater. Old subcutaneous rock forms reshaped by trickling water also survive higher above the ground. However, we must distinguish between the subcutane- ous shaping of rock that is specifically the consequence of the composition of the rock, its joint frequency and stratification, that is, the points of weakness in the rock, from subcutaneous rock forms created by characteristic factors. Due to relatively even dissolution of the rock below the soil and the sediment, the rock is rounded so that the subcutaneous forms are of the same type and the surface of the rock seems rela- tively smooth to the eye or characteristically rough on the variably composed or recry- stallized carbonates. Under great magnifica- tion, the under-sediment rock surface, as a rule, is distinctly finely rough due to the even corrosion of the grained rock (Slabe 1994). kitkras1.p65 3.12.98,3:39 52 Black 53 1 1 Tadej Slabe Rock Relief of Pillars in the Lunan Stone Forests Below the sediment and soil, large (Fig. 1.5.1.) and small subcutaneous chan- nels occur. Vertical channels range from twenty centimeters to one meter and more in diameter (Chen Zhi Ping et al. 1983, 605). They occur when larger amounts of water continuously flow along the permeable con- tact with the rock. The largest channels can be wide and shallow and also deep along fissures where the channels are most fre- quent. The size of the diameter of the semi- circular subcutaneous channels can vary. Deep under the soil and sediment, the large channels are often distinctly narrower. Therefore, the rock dissolves fastest at the upper part of the soil and sediment. Along the more distinct fissures, a subcutaneous shaft with soil at the bottom can occur in the middle of the pillar. In Lao Hei Gin, subcutaneous channels may be preserved on the harder stone tops and feet. They are several meters wide and up to half a meter deep and dissected by small subcutaneous recesses. Channels are visible at all heights only on pillars that are close together. The pillars are therefore un- dercut and overhang considerably. On the upper parts of the pillars, the subcutaneous channels are distinct only on lower pillars that have not been denuded long enough for the rainwater to reshape them to a larger degree. As a rule, they no longer exist in the denuded middle sections of the pillars due to the fine disintegration of the rock. Smaller channels (Fig. 1.5.2., 1.5.3.) five to twenty centimeters in diameter cross the wall at various angles and can have wind- ing shapes. They are evenly wide along their entire length or wider at the contact with other channels. They can also be linked in a network. Channels also occur in the lower sec- tions of the pillars in the Shilin Central For- est which is composed of layers of lime- stone with large lenses of chert in them. There are no minor rock forms on them. Larger rounded and shallow channels are also found on the pillar walls in Naigu. Smaller rock forms are not found on such rock or they are indistinct due to the com- position of the rock or its decay. Channels therefore appear under sedi- ment and soil, and when the level of the sediment drops, the denuded parts of the Fig. 1.5.1. Large subcutaneous channel (Photo T. Slabe) kitkras1.p65 3.12.98,3:39 53 Black 54 1 1 Tadej Slabe Rock Relief of Pillars in the Lunan Stone Forests pillars are reshaped by rainwater. Their sur- face is therefore dissected by small recesses. Below deep channels formed by rainwater on the tops of pillars, their lower parts un- der overhangs are shallow and wider, only partly reshaped by rainwater. As a rule, the most winding are subcuta- neous small channels (Fig. 1.5.3.) between one and five centimeters in diameter. Small channels often run obliquely down the walls and curve by as much as 90. They ei- ther stand individually or are connected in characteristic rhombohedral grids. Subcutaneous large and small channels develop mainly through the soaking of the soil and sediment at the permeable contact with the rock and not through distinct mi- nor streams, a fact reflected by the network of small channels and their dissection with small horizontal notches. Small tubes through which water flows occur only at the bottom of channels. At the contact point, the dissolving of the rock is more dis- tinct and longer lasting. The size and the shape of the large and small channels are dictated, along with the composition of the rock, primarily by the permeability of the Fig. 1.5.3. Subcutaneous channels (Photo T. Slabe) Fig. 1.5.2. Small subcutaneous channels (Photo T. Slabe) kitkras1.p65 3.12.98,3:39 54 Black 55 1 1 Tadej Slabe Rock Relief of Pillars in the Lunan Stone Forests the bottom of the cracks between the pil- lars or teeth where the fissures are wedged out or where the channels crisscross the tops of larger subcutaneous teeth (Fig. 1.5.5.) or lead from subcutaneous recesses (Fig. 1.5.5.). The water flowing along per- meable contacts with the rock accumulates at the bottom of cracks and recesses, and the soil therefore preserves its ability to dis- solve the rock for a longer period. Under a thinner layer of soil, in most cases in the vicinity of large and small sub- cutaneous recesses, there are, as a rule, gradually sloping channels with semicircu- lar bottoms. They occur with the accumu- lation of the water that percolated through the soil. Underneath the soil, they also deepen quickly when only their bottom is covered. On larger rocks, systems of chan- nels developed. Smaller subcutaneous chan- nels unite radially into a larger channel due to the gravitational flow of the water. In the following chapter, channels will be de- scribed that formed due to the draining of water from subcutaneous recesses and from solution pans on the tops of the pil- lars. The vegetation was removed and the water carried away the weathered debris. Subcutaneous channels must be distin- guished from the subcutaneous channel- like notches that are merely the conse- quence of stratification and the way the rock has been crushed. The largest subcutaneous scallops are a unique feature, similar to large and open scallops with smooth walls. Their diameters are fifteen to fifty centimeters and they are shallow. As a rule, they are found on over- hanging surfaces (-5 to -20; Fig. 1.2.3.). Most frequently, they are slightly deeper on the upper side and connected in a network. Larger recesses also occur on overhanging walls of pillars that have been exposed to rainwater for a longer period. For the time being, I am of the opinion that they devel- oped during contact with fine-grained sedi- ment. This supposition is also proven by rock dissected by recesses whose yellow surface is rounded and smooth. Such is of- ten the case on rock at the contact with sedi- ment or soil and when the water drains from it. They are also similar to the subcu- Fig. 1.5.4. Subcutaneous channels (Photo T. Slabe) contact with the soil and the quantity of the water flowing over the contact point. The less permeable the contact is, the more winding small channels develop. The char- acter of the contact between the wall and the soil can vary or change in places. Wind- ing small channels can therefore occur on the walls of larger channels (Fig. 1.5.3.). At poorly permeable contact points, subcuta- neous channels are the largest along the level of the sediment and soil, while below it they narrow quickly. Gams (1997) also establishes a connection between the growth of underground caverns and the permeability of their fill. In old caves with- out ceilings, the contact between the clay and the wall has not been reshaped in most cases from the period of the fine corrosion of the rock when the moist fine-grained sediment was deposited (Slabe 1997). Unique vertical or horizontal subcutane- ous channels (Fig. 1.5.4.) with semicircular or omega-shaped cross sections appear at kitkras1.p65 3.12.98,3:40 55 Black 56 1 1 Tadej Slabe Rock Relief of Pillars in the Lunan Stone Forests taneous rock forms that can be observed at distinct fissures along which cracks develop filled with soil and which have been de- nuded by land works in Kras (Slovenia). Along fissures crisscrossing the rock or at distinct bedding planes, recesses of this type as a rule do not occur, but rather a semi- circular channel develops beside them. It appears that the recesses occurred because of the distinct flowing of the water along the contact with the rock and the percola- tion of water through the porous soil and sediment. Soil or sediment of this type of- ten contains particles of rock or rubble. Along-sediment recesses also occur fre- quently on the walls of caves filled by fine- grained sediment. In the stone forests, they are visible only in individual places. For the moment, I can concludethough I will also try to verify this with tests with gypsumthat large and small channels oc- cur mostly due to the percolation of water at the contact of the rock with the less po- rous sediment and soil, while recesses oc- cur at distinctly porous sediment and soil when a larger quantity of water trickles down the contact and simultaneously per- colates through the soil and sediment. The latter can be found only rarely in the Lunan stone forests. Under the thin layer of porous soil that covers the rock in some places only in spots and elsewhere entirely, hemispherical small and large recesses (Fig. 1.5.6.) oc- cur. The former are one to five centimeters in diameter, the latter are larger. They oc- cur due to the percolation of water through the soil. The water moistens the soil in the small recesses and, as a rule, enlarges them in a hemispherical way when the rock is surrounded by fine-grained sediment or soil. The recesses in most cases lie side by side or are already connected. The subcu- taneous channels described often lead from them. From recesses on level surfaces, so- lution pans can be formed when the major- ity of the soil is washed away. Trudgill (1986, 468) says that the subcutaneous re- cesses and channels only occur underneath acidic soils. Separately, we can single out rock shapes that occur at long-lasting levels of Fig. 1.5.5. Subcutaneous channels (Photo T. Slabe) kitkras1.p65 3.12.98,3:40 56 Black 57 1 1 Tadej Slabe Rock Relief of Pillars in the Lunan Stone Forests sediment and soil. These are subcutane- ous notches, bells, and half-bells shaped by rainwater that trickles to the bottom and then flows between the rock and the soil. Smaller subcutaneous notches, ten to twenty centimeters in diameter, have the form of semicircular horizontal channels, except their upper edges are sharper in most cases while the lower edges are rounded, assuming, of course, the entire subcutaneous notch has not been reshaped by rainwater. Larger subcutaneous notches (Fig. 1.5.7.; undercut notches Waltham 1984, 182; Ford et al. 1997) are indented into the rock by one meter and more, and the largest I have seen are up to one meter high. The lower part of the notches is un- dercut as the rock has been subjected to faster, longer-lasting dissolving under the moist ground and is therefore rounded and smooth. The bottom of the notch is hori- zontal and the upper part lowers toward the bottom in a semicircular fashion. The up- per part of the notch has been reshaped due to the trickling of rainwater. Notches can be seen at various heights of the pillars at long-lasting levels of soaked ground. Smaller and exposed notches are more distinctly reshaped by rainwater while larger notches are less distinctly reshaped. Half-bells (Fig. 1.5.8.) occur below chan- nels that lead larger quantities of rainwater trickling down the pillars to the sediment. Above the soil and sediment, the expan- sions have characteristic bell-shaped and half-bell-shaped forms. Their shape and size are linked to the quantity of water reach- ing the soil, the permeability of the contact between the rock and the soil, and the du- ration of the level of the soil or sediment. When formed along a distinct fissure, the upper part of the channel can also be a tube, while the wall is only weathered at the area of expansion. The walls of bells from which the soil was recently removed are dissected with oblong subcutaneous recesses reach- ing up to one meter in diameter. Large bells also occur between the pillars. The upper parts of half-bells and bells are reshaped by trickling water that gives them the distinct semicircular form. Below, above the soil, the bell-shaped expansions most frequently Fig. 1.5.6. Subcutaneous recesses (Photo T. Slabe) kitkras1.p65 3.12.98,3:40 57 Black 58 1 1 Tadej Slabe Rock Relief of Pillars in the Lunan Stone Forests gradually narrow into subcutaneous chan- nels. First, smaller semicircular notches oc- cur, and larger notches then grow during the slow lowering of the level of sediment. The rapid lowering of sediment causes these forms to remain hanging on the walls of the pillars. Poorer permeability of the contact below the notches and subcutane- ous bells is also proven by small subcutane- ous channels. In short, notches and bells occur when more water flows to the contact with the soil or the sediment surrounding the pillars than the contact or the unevenly porous sediment can immediately conduct, and the dissolving of the rock at this spot is there- fore faster. The forms described are distinguished from the notches that occur because of the often faster dissolving of the rock along the bedding planes that are almost horizontal in Shilin. As a rule, these notches are nar- rower and often relatively deep in relation to the diameter of the opening. Cracks occur along the vertical fissures that crisscross carbonate stone in various networks, and between them are subcuta- neous stone teeth. The cracks often have their cross sections in variously wide and deep V-shapes. At their bottoms, subcuta- neous channels are frequent. With densely distributed teeth, only narrow cracks can occur, from 0.2 to 0.75 meters in diameter and usually up to two meters deep. Such stone teeth are stubby under the ground and on the surface. Narrow and pointed teeth occur, though, when the crack-like notches between them are up to two me- ters wide and more than five meters deep. In the latter case, only narrow and relatively low points reach the surface. Of course, there are numerous intermediate varia- tions. The differences in their shapes are the consequence of the properties of the fis- sured rock, the type of sediment, and the duration of the dissolving of the rock un- der the ground. The type and composition of the stone is not reflected in the shape of the subcutaneous stone teeth as much as on the surface where it defines the shape of the pillars and to a large degree their rock relief as well. Subcutaneous stone teeth are Fig. 1.5.7. Subcutaneous notche (Photo T. Slabe) kitkras1.p65 3.12.98,3:40 58 Black 59 1 Tadej Slabe Rock Relief of Pillars in the Lunan Stone Forests quite regularly pointed and rounded. Such is the case in the Naigu and Lao Hei Gin for- ests. They have semicircular subcutaneous rock forms, while fissures or bedding planes also show here along which semicir- cular notches occur. The water therefore reaches and shapes the underground teeth relatively evenly. The water flowing along the contact of rock and soil or percolating through the soil to the rock accumulates in the recesses that occurred at weak points in the rock, and from there it flows down the stone teeth. Subcutaneous channels occur at the bottom of the cracks between the teeth, they can cut across the tops of the stone teeth, or they can appear as outflow channels from subcutaneous recesses. However, due to the lowering of the level of the soil, the soil been preserved only on the bottoms of channels where water has deepened and expanded them. The pillars in the stone forests are often crisscrossed by subcutaneous tubes and anastomoses that originated at distinct bedding planes, fissures, or in porous rock. Water also deposited sediment in the origi- nally small tubes that became wider in the process. The pillars in the Lao Hei Gin stone for- est are perforated by tubes in their middle and lower sections, that is, in layers of dis- tinctly porous rock, while these are practi- cally non-existent on the tops and at the feet of the pillars. They penetrate deeply into the rock, and some run through the pillars. The bottoms of the semicircular tubes, on top of which are often smaller above-sediment channels, are clayey if they are situated in the layer of sediment and soil. Above-sedi- ment ceiling channels occurred when the level of the subcutaneous tubes was under the soil. The tubes were filled with sedi- ment, above which smaller quantities of water flowed. The size of the tubes, which reach 1.5 meters in diameter, and their branching, indicate the long duration of the formation. Individual systems are the size of smaller caves. Fig. 1.5.8. Subcutaneous half-bells (Photo T. Slabe) Fig. 1.5.9. Subcutaneous tube (Photo T. Slabe) kitkras1.p65 3.12.98,3:41 59 Black 60 1 Tadej Slabe Rock Relief of Pillars in the Lunan Stone Forests The majority of subcutaneous tubes (Fig. 1.5.9.) in the pillars of the Shilin stone for- est are smaller. They occurred at fissures in the middle sections of the pillars. Only in- dividual tubes are larger, reaching up to two meters in diameter. In most cases, their cross section has the shape of a horizontally elongated ellipsis. As a rule, there are chan- nels (Fig. 1.5.10.) on their bottoms formed when the level of the sediment encircling the pillars dropped and the water flowed only along the bottoms of the channels. In Naigu, large tubes occurred at the contact between the harder and non-fis- sured tops and the lower, thinner layers of rock. In most cases, they are not larger than one meter in diameter, although some are genuine tunnels. Rock forms carved by rainwater on the pillars of the stone forest The most beautifully developed rock relief with rock forms of this type is found in the Shilin (central) stone forest. In the relatively pure and thickly layered lime- stone with relatively even composition, unfissured, and not particularly dolo- mitized, distinct rock forms developed due to rainwater. The most distinct and diverse is the rock relief formed by rainwater on the upper five meters of the pillars, while the tracks of trickling water on vertical and slightly inclined walls reach all the way to the feet. There are also surfaces, however, that the rainwater does not reach directly. Deeper notches occurring at bedding planes or levels of sediment of longer dura- tion are smooth or have points only on the initial part of their ceiling. J. Kogovek (chapter 1.6.) identified the significance of various types of rain that influence the speed of the dissolving of the pillars due to variations in the thickness of the film of water they create on the rock. The first subgroup of rock forms directly or indirectly shaped by rainwater consists of small and large channels. On the up- per parts of pillars, small channels (Fig. 1.5.11.; Rillenkarren Bgli 1981; Sweeting 1995; Chen Zhi Ping et al. 1983)) are found Fig. 1.5.10. Subcutaneous tube (Photo T. Slabe) kitkras1.p65 3.12.98,3:41 60 Black 61 1 Tadej Slabe Rock Relief of Pillars in the Lunan Stone Forests on evenly fine-grained rock. Semicircular (parabolic Glew and Ford 1980) small channels, one to three centimeters wide and from several centimeters to several dozen centimeters long, run parallel to one another, that is, linked in a network. The more evenly fine-grained the stone is, the more regular the forms of the small chan- nels and the straighter the ridges between them are. The curvature of the ridges and the dissection of small channels into small recesses, a characteristic of small channels especially on steeply inclined surfaces (Slabe 1995), are the result of the composi- tion and recrystallization of the rock. Small channels occur on sloping and gently in- clined surfaces. Glew and Ford (1980, 27) established that they occur on surfaces in- clined from 12 to 70. On gently inclined surfaces, they are similar to one another and equal, while on steeper rock surfaces they unite into larger, mostly shallow channels (Fig. 1.5.11.; Regenrinnenkarren) that are therefore distinctly ribbed in the upper part. Small channels, connected in this way can also be found in caves formed under a thin flysch cover (Slabe 1995). On steep pointed pillars, only shallow less distinct small channels dissecting larger channels occur on the ridges. On wider tops of the pillars, the water from the small channels flows into shallow, wider, and gently in- clined channels (Fig. 1.5.11.). Small chan- nels occur when the film of water is still thin and does not prevent rain from direct con- tact with the soluble rock; however, when the film is thick enough, flat surfaces (Glew & Ford 1980, 25) or the channels described above occur that are therefore a character- istic form below the small channels. The small channels in the Naigu stone forest are only found on dolomite limestone tops of pillars. They are winding and their ridges are not level. They are often arranged radially around lenses of slower dissolving rock. In the Lao Hei Gin stone forest, the rainwater flows down a network of one to two centimeter deep and similarly wide at the top small notches that occur along thin, densely distributed fissures. The ridges be- tween them are narrow but rounded. Forti (1977, 10) determined the various sizes of Fig. 1.5.11. Small channels carved by rainwater (Photo T. Slabe) kitkras1.p65 3.12.98,3:41 61 Black 62 1 Tadej Slabe Rock Relief of Pillars in the Lunan Stone Forests small channels on different rock. The most regular forms occur on micrite (Forti 1977, 11). As a rule, this applies to all rock forms on evenly fine-grained rock (Slabe 1995). Individual small channels and channels that most frequently have diameters up to fifty centimeters are of different origin. The first, whose diameters reach up to fifteen centimeters, are characteristic of the steep and vertical upper sections of pillars. Small channels unite in them (Fig 1.5.11.). They are frequently dissected only by less distinct horizontal ridges. They begin on sharp tops or ridges and can unite in a larger channel that is straight or widens downward, the case especially on ridges. On the tops of the pillars are forms that are often similar to open funnels with gently sloping sides cov- ered with small channels, while larger chan- nels occur on the steeper walls below them. This is the most frequent form found on rock tops in general, not just in the Lunan stone forests. For the moment, I judge that the funnels are the legacy of subcutaneous channels. That is, semicircular subcutane- ous channels wider at the top most fre- quently indent the stone teeth. The chan- nels also occur due to the outflow of water from only slightly inclined and shallow channels that occurred on more extensive tops of pillars below small channels (Fig. 1.5.11.). The walls of the upper sections of pillars are thus entirely dissected with small channels and channels with only smaller or larger ridges between them. On stocky tops of pillars there are frequent subcutaneous recesses, although solution pans prevail af- ter rapid denuding. Channels occur due to the outflow of water from either. Larger and deeper channels on the tops of the pillars widen in a funnel-like manner. The form of individual large and small channels of dif- ferent sizes is also the consequence of the composition and joint frequency of the rock on which they occur and the inclina- tion of the surface into which they indent. Their form is therefore also the legacy of the subcutaneous dissolving of the rock. Channels with diameters of one to fifty centimeters also occur as walls of deepen- ing solution pans or subcutaneous recesses. They end with rocky jags that are the re- mains of the bottoms of the solution pans. According to HabiŁ (1980), the deep chan- nels with sharp edges also found on fallen pillars developed in a more humid climate with heavy downpours. Large channels in the Naigu stone forest are more shallow and rounded, and their ridges are less sharp. Smaller channels are not often found on this characteristically composed rock. In the Lao Hei Gin stone forest where small channels are indistinct or even non-existent due to the composition of the rock or its decay, individual channels full of small cracks oc- cur along vertical fissures. The second subgroup of rock forms hol- lowed by rainwater trickling down the walls of pillars are various small and large recesses on vertical and overhanging walls where the rock is unevenly composed or fissured on inclined surfaces and ceiling points on the overhangs. I have previously described these forms as they occur on cave walls (Slabe 1995). They occur due to the way water trickles on rough or fissured rock. In most cases, evenly fine-grained rock that has not been reshaped by other factors is almost vertical and relatively smooth (Slabe 1990). Researchers who have de- scribed recesses (Sweeting 1995; Chen Zhi Ping et al. 1983) classify them as small (with only one-centimeter diameters), medium (five to fifteen centimeters in diameter), and large (with diameters reaching thirty centimeters). Their size probably reflects the speed of the water flowing down the rock and its hydraulic characteristics (Sweeting 1995). I have attempted to sup- plement their observations and more accu- rately define the origin, size, and shape of recesses. Small and large recesses also dis- sect the walls of large and small channels where the recesses are of the same width. These are often smaller rock forms occur- ring inside larger forms. According to their size, I divide them into small recesses with diameters from 0.5 to five centimeters and large recesses most frequently having diameters between five and ten centimeters. We can learn more about them from their division according to the manner of occurrence and shaping. Small and large recesses of this type occur kitkras1.p65 3.12.98,3:41 62 Black 63 1 Tadej Slabe Rock Relief of Pillars in the Lunan Stone Forests due to the trickling of water down rough rock surfaces with varying inclinations. Their development, especially of the small- est, is therefore determined by the relatively even fine-grained composition of the rock down which the water trickles swirling along the rough surface. Small channels on vertical walls are dissected by short small recesses of the same width. Their edges are therefore jagged. Small recesses are also found on the walls of vertical channels and linked in columns. They are similarly ar- ranged on the ridges of pillars. Their ar- rangement into lines indicates smaller quan- tities of water trickling down the vertical rock. In narrow cracks between pillars, small recesses on the projecting parts of the rock can be also obliquely oblong, one centimeter wide and three centimeters long, indicating a strong air current that in- fluences the direction of the trickling wa- ter. There are small recesses on overhang- ing walls that are deeper on the flowing side and joined in a network. Most frequently, they are 0.5 centimeters long and one centimeter wide. They are relatively deep and therefore have distinct edges. On the overhangs, the recesses are smaller below channels where a larger quantity of water flows faster with diameters up to one centimeter, while on the surrounding over- hanging surface of the same inclination, they can be larger with diameters reaching three to five centimeters. On the ceiling, small recesses pass into ceiling points. These usually have a triangular cross section with rounded tops. They occur due to the uneven dissolving of the grained rock un- der a thin layer of water flowing across the ceiling. The water accumulates on particles of rock protruding from the ceiling, but because it is less corrosion-effective, the distinction between the ceiling points and the small recesses between them increases (Slabe 1995, 79). Characteristic small re- cesses occur along tiny vertical fissures. They usually have a teardrop shape (Slabe 1995, 97). The walls above horizontal bedding planes are dissected in a characteristic semi- kettle fashion. The large recesses are three to twenty centimeters in diameter. Smaller ones are hemispherical, while larger ones have flat, circular bottoms constituting the upper layer of the lower bed. Above the bottom is an overhanging wall. Large re- cesses are usually teardrop shapes hollowed into the wall and composed of small re- cesses that occurred due to the trickling of water toward the bedding plane. Large re- cesses grow from the bottom up and often occur side by side. The largest recesses, up to thirty centi- meters wide, occur on overhanging walls and were, as I conclude for the moment, formed at the contact with fine-grained sediment and soil surrounding carbonate rock, and are therefore not the conse- quence of rainwater trickling down the overhanging walls of the pillars. The occurrence of small and large re- cesses is determined particularly by the grainy composition, joint frequency, and stratification of the rock, while their size and shape is influenced by the different quantities of water that trickle down the surface of rock of different inclinations at various speeds. On vertical and inclined rock surfaces, smaller amounts of water unite into streams, while small and large recesses and ceiling points develop on over- hanging rock surfaces due to the character- istic gravitational spreading of the water. According to research done so far, it does not appear that the size of the small and large recesses is only the trace of the speed of water over rough surfaces (Sweeting 1995, 127) or that large recesses are just a varia- tion of smaller ones, as is the case in caves where streams of water flow over different rocks and hollow out scallops (Slabe 1995). I believe that the largest recesses occur- ring on the overhanging walls of pillars were formed under fine-grained sediment and soil. On the pillars, there are also various so- lution pans. These are small depressions formed by rainwater on horizontal or gen- tly sloped surfaces of the rock. They range from one centimeter to one meter and more in diameter and can be equally deep. The smallest, up to ten centimeters in diameter, are usually hemispherical with mostly flat bottoms. They often occur side by side with kitkras1.p65 3.12.98,3:41 63 Black 64 1 thin rims between them. The largest solu- tion pans occur along fissures between pil- lars, and their forms are dissected accord- ingly. Solution pans are frequently most dis- tinct on the tops of lower formerly covered pillars that were recently denuded. They were covered with soil and vegetation, and the pillars retained horizontal tops. Subcu- taneous recesses therefore in most cases developed into solution pans. The develop- ment of subcutaneous recesses into solu- tion pans was also identified by Gams (1971, 32) and Zhang Shouyue (1997, 79). On the walls of such pillars, the previously described subcutaneous channels formed under the soil also occur. In the Lao Hei Gin and the Naigu stone forests, the solution pans have various forms and their edges are jagged as a result of the properties of the rock. In the Lao Hei Gin stone forest, solution pans develop from small recesses occurring under the vegetation, as the development of solution pans is usually described (Perna 1996, 393). Small solution pans up to ten centimeters wide and two to three centimeters deep on the tops of the pillars developed in lenses of more rapidly dissolving rock. Solution pans on various rock have been described by Forti (1972). Deepening solution pans and subcuta- neous recesses often occur on the walls of pillars, and above them are channels that are actually their former walls. Such solu- tion pans can also be small, only one centimeter in diameter. They look like the bottoms of small channels of different lengths and therefore can be found at vari- ous heights of the wall. Algae and soil are often found in solu- tion pans, which accelerates their growth. This is also proven by the quantity of dis- solved limestone which is higher in solu- tion pans (Sweeting 1995). The contents of dissolved carbonates in the water in solu- tion pans and the change during rain has been studied by J. Kogovek (chapter 1.6.). The properties of the rock, particularly its composition and joint frequency, have a distinct impact on rock relief hollowed by rainwater and on its surface. Tadej Slabe Rock Relief of Pillars in the Lunan Stone Forests The surface of distinctly unevenly com- posed rock is rough, while the surface of fissured rock is angular due to fine crum- bling. On distinctly rough rock surfaces, there are none of the characteristic de- scribed forms hollowed by rainwater that are smaller than the constituent parts of the rock or are their traces of irregular forms. This is especially true of dolomite or dolomitized carbonate rock and limestone with chert. Small channels therefore usually do not occur, although channels of medium size occur on more finely rough surfaces. Large channels, apparently originally sub- cutaneous, are relatively shallow and of ir- regular form and are found on the rough- est surfaces. Ring-like solution hollows (Chen Zhi Ping et al. 1983) often occur around the bulbs of chert. In the Naigu stone forest, dissected solution pans occur on the tops of pillars with relatively wide and flat tops, while indistinct irregular small channels are found only in the sections of the most evenly grained rock. The tops of the small channels are made of the bulbs of slowly soluble rock. The majority of the rock surface is relatively coarsely rough due to the composition of the dolomite lime- stone (Ford et al. 1997). Differences in sedi- mentation, mostly bedding planes, are re- flected in the rock relief. I classify the roughness of the rock sur- face in the Naigu stone forest into three form varieties. From the surface of pointed tops in the middle part of the forest, rela- tively densely distributed oblong points protrude, one to three centimeters long. On such rock, only medium and large channels occurred, while small channels only oc- curred on individual sections. In the lower parts of the pillars, »bulbs« protrude from the rock. The bulbs, whose surface meas- ures ten and more square centimeters, are rarely pointed and protrude up to three centimeters from the rock. Between them are large surfaces of the basic rock plane. The surface of protuberances and the rock between them is rough. Larger notches in- dent the protuberances, and smaller re- cesses whose diameter reaches at most one centimeter are found in the rock between them. Thinner dissected plates also pro- kitkras1.p65 3.12.98,3:41 64 Black 65 1 Tadej Slabe Rock Relief of Pillars in the Lunan Stone Forests trude from the rock surface. They reach up to ten square centimeters and in most cases are connected with narrow belts of pro- tuberances. The proportion of the surface of the protuberances is equal to the propor- tion of the rock between them. The surface of the protuberance is dissected by small recesses up to one centimeter wide. Ford, Salomon, and Williams (1997, 115) believe that the protuberances also occurred through recrystallization around small holes that were probably filled with gypsum originally. M. Knez states, while studying the pillars, that roughness of the rock is con- trolled by being strongly tectonically bro- ken, recrystallized and dolomitized. Rock surface formed under vegeta- tion on the pillars of the stone forests Rock surface under vegetation and a thinner layer of soil is of varying roughness, and subcutaneous small recesses and small channels are found under somewhat thicker layers of soil. The rock below compact vegetation and thinner or only patchy soil is often corroded into forms dictated by the composition, by the way the rock has been crushed, and the stratification of the rock. Up to two centi- meter wide, in spots only slightly deeper, oblong small notches reflect the diverse stratification of the rock and bedding planes. Finely and densely crushed rock is dissected by a network of equally-sized small notches (Fig. 1.5.12.). Often, only the broader tops of the shorter pillars or their lower parts and the notches along bedding planes are formed like this, in short, for- merly overgrown parts. Above the de- scribed dissections, small and large chan- nels and small recesses dominate if the rain- water is able to flow across the rock rela- tively unhindered. The same rock is either smooth or dissected with rounded small recesses if it was reshaped under the soil. The rock surface under the vegetation is often dissected by one millimeter small recesses. On the tops of pillars in the Lao Hei Gin stone forest, small recesses devel- oped under moss with diameters of one to Fig. 1.5.12. Rock surface formed under vegetation (Photo T. Slabe) kitkras1.p65 3.12.98,3:41 65 Black 66 1 ten centimeters and up to five centimeters deep. A large proportion of the pillars are covered by lichen and moss, the dark sur- face of the Naigu stone forest is the conse- quence of algae on the rock (Ford et al. 1997, 114), and the rock surface is there- fore characteristically finely corroded (Slabe 1995). Moses and Viles (1996) estab- lish the importance of biologically created nanomorphology, but in spite of the fact that small recesses develop under lichen, rain still decisively shapes the rock. Fiol, Forns and GinØs (1996) draw attention to the great importance of the mechanical re- moval of larger pieces of rock isolated by biocorrosion under the algae that covers the small channels. Small and densely distributed subcuta- neous recesses and subcutaneous channels (described among the subcutaneous rock forms) developed under the vegetation and soil. Biocorrosion also accelerates the de- velopment of solution pans described with the forms hollowed by rainwater. Channels formed due to the draining of water from subcutaneous recesses on the tops and gently sloping parts of the pillars and strongly corroded rock surfaces indi- cate the considerable importance of the long-lasting covering of the rock by a thin layer of soil and vegetation for the forma- tion of the rock relief. Conclusion In the rock relief of pillars in the stone forests, there are crisscrossed traces of the original shaping of the rock under the soil and sediment, marks indicating the lower- ing of level of soil and sediment, and traces of later more distinct reshaping of the pil- lars by rainwater, largely, of course, on the tops. This type of rock relief is best seen on the pillars in the Shilin Central Forest, that is, on relatively evenly composed carbon- ate rock. With the lowering of the level of the sediment and soil surrounding the car- bonate rock, the original subcutaneous rock relief of the stone forest pillars has been in some places more and in others less effectively reshaped by rainwater. Subcutaneous rock forms are divided into three types. The first rock forms oc- cur under sediment and soil, the second occur at the level of sediment and soil, and the last occur under thin layers of soil that covers the rock in places. Through the pil- lars, subcutaneous tubes of various sizes oc- curred along fissures or bedding planes under the ground. Distinct subcutaneous forms testify to the efficient dissolving of carbonate rock under the ground. Below sediment and soil, larger and straight as well as smaller and winding subcutaneous chan- nels occurred along the contact of the soil and rock due to the flow of water. Large subcutaneous recesses occur on vertical or overhanging walls because the rock is sur- rounded by porous sediment and the con- tact between them is more permeable. Also the frequent overhanging narrowing of pil- lars below their tops is the consequence of the more rapid dissolving of carbonate rock under the soil and sediment. At long-last- ing levels of soil and sediment, horizontal subcutaneous wall notches and subcutane- ous half-bells formed due to rainwater trick- ling steadily down the walls of the pillars and then slowly flowing along the contact with the soil. Subcutaneous small recesses and channels occurred under thin layers of soil due to the percolating of water through it. Small channels formed on the sharp tops, as a rule occurring in funnel-shaped notches that developed from the begin- nings of former under-sediment large chan- nels. On steep walls, they combine into large channels. Large channels also occur below funnel-shaped notches and when the water drains from subcutaneous recesses and solution pans. Vertical and overhang- ing walls are also dissected by various small recesses hollowed by rainwater and on the most overhanging sections by ceiling points. Solution pans occur on gently slop- ing sections. The progressive reshaping of the rock relief is also indicated by com- posed, originally subcutaneous channels whose upper parts have been reshaped by rainwater and whose lower parts continue into artificially opened and wider subcuta- neous channels. The contact at a long-last- Tadej Slabe Rock Relief of Pillars in the Lunan Stone Forests kitkras1.p65 3.12.98,3:44 66 Black 67 1 ing level of soil and sediment is bell-shaped and the wall is overhanging. That the pillars were overgrown is best seen on broader tops, on gently sloping walls, and just above the ground. Rock sur- faces that were overgrown are characteris- tically finely corroded. The rock relief is most easily readable on the pillars in the Shilin Central Forest, that is, on quite evenly composed carbon- ate rock. The varieties of characteristic rock relief and, of course, the shapes of the pil- lars and their development were dictated primarily by the properties of the rock. On the tops of the Naigu stone forest, unique small channels occurred due to the compo- sition of the rock, while on the tops of the Lao Hei Gin stone forest, they occurred due to tiny fissures. The rock surface of the pil- lars in the Naigu stone forest is rough, with large surfaces of slower soluble parts of the rock protruding from it. Even the channels hollowed by rainwater mainly occurred only along vertical fissures. The rims of so- lution pans are strongly jagged. Subcutane- ous forms are less distinct and dissected. Along the bedding planes in the Naigu stone forest and in the middle part of the pillars in the Lao Hei Gin stone forest where the rock is most porous, large tubes occurred that penetrate the pillars. Under the ground, fissured carbonate rock is shaped into subcutaneous karren (Fig. 1.2.2.). Between the cracks are rock teeth and smaller pillars with characteristic rock relief containing subcutaneous rock forms. Subcutaneous channels with semicir- cular or omega-shaped cross sections and subcutaneous recesses first occur under the soil and sediment. These forms can also criss- cross the tops of subcutaneous teeth. With the lowering of the level of the soil, in most cases the result of the development of an underground water network below the for- est, protuberances emerge and are further reshaped by rainwater. From the rounded channels and cracks cutting across the tops of subcutaneous teeth, sharp funnel-shaped Tadej Slabe Rock Relief of Pillars in the Lunan Stone Forests notches begin to form along with small chan- nels on them. As the level of sediment and soil lowers, the reshaping continues down- wards. The rock forms hollowed by rainwa- ter are originally determined by the initial subcutaneous forms. The rock relief reveals the way the stone forests were formed and presents the course of their development. Rock forms that develop at the level of soil reflect the duration of the soil level at particular points in time. Rock forms of this type captured in the walls therefore reveal periods of the intermittent lowering of the level of the soil. We must also be aware of mans impact on the stone forests, especially in those open for tourists where the cracks between the pillars have been deepened in many places. I also link the rock relief on the pil- lars with the rock relief in the caves below the forest. Here too we find characteristic traces of distinct changes in their perme- ability. Signs of fast water flowing through the tunnels alternate with the filling of the caves with pebbles or fine-grained sedi- ment over which above-sediment channels occurred. The flow of water through the caves in certain periods was small. I believe that the water also occasionally flowed on the surface between the stone pillars and that the level of sediment remained un- changed for long periods. In most places, the level of underground water below the forest is close to the surface, which means that more recent factors can quickly cover the traces of older factors. This type of com- parison and reading of the rock relief as the traces of the development of the stone for- est therefore calls for further in-depth re- search, more precise comparison of the lev- els of characteristic cave and surface rock forms, and comparison with other develop- mental indexes such as various sediments. I also plan to continue the research on the origin and development of the stone for- ests and their rock relief with laboratory tests using gypsum to verify many other hy- potheses. kitkras1.p65 3.12.98,3:44 67 Black 68 1 Janja Kogovek Rock Dissolution in Stone Forests In July 1996 we studied the precipitation and carbonate rock dissolution characteris- tics in Shilin stone forest and in Naigu stone forest in the vicinity of Lunan. The average annual precipitation is approximately 800 mm, the average relative humidity is 75 % and the average annual temperature is 15.6 C. The annual amount of precipitation has been very variable through the years, al- though over 80 % of all annual precipitation occurs during the rainy season, roughly from June to October, during the period with higher temperatures. We took and analysed rain samples re- peatedly, we examined recent dissolution of stone blocks during rain and the dissolu- tion in cups in Shilin stone forest and the intensity of carbonate rock dissolution by vertical movement of precipitation from the surface to the vadose zone into the un- derground Baiyun and Xinshidong caves in Naigu stone forest and into Jiuxiang cave. Research Methodology Samples of rain were taken in Shilin stone forest near the hotel and placed into polyethylene containers. We analysed them immediately. The samples for examining the dissolution of stone blocks in Shilin stone forest were taken from the base of the selected blocks, while it was raining. The percolated water in the caves was in most caves sampled directly from the cave ceil- ing. We measured larger discharges by us- ing a stopwatch and a measure, and esti- mated smaller discharges by the quantity of water caught in a certain amount of time. 1.6. ROCK DISSOLUTION IN STONE FORESTS Janja Kogovek While we took samples in the field, we also measured the water temperature to the ex- actness of one tenth of a degree and the specific electric conductivity (SEC) to 1S/ cm (July 1996 with an LF 91 WTW appa- ratus, September 1997 with LF 196) and also the pH of the samples (pH 90 WTW apparatus). The comparison and intercalibration of both conductivity meters indicated a fairly good correspondence. In the area of 150 to 250 S/cm we defined from 1 to 0 % exces- sively low numbers and in the area of 250 to 500 S/cm for 0 to 1 % excessively high numbers. Carbonate, Ca and Mg content, as well as overall hardness were determined titrimetrically according to standard meth- ods (Standard Methods of the Examination of Water and Wastewater 1992). Rain composition Yuan Daoxian (1991) described the fol- lowing rain composition: pH, calcium, mag- nesium, sodium, and chlorides, sulphates, nitrates, and ammonium for some of the areas of China, but not for the Yunnan area. He studies the effect of the bedrock and the effect of human activities such as smoke and pollution caused by cement plants and stone-pits. He also states that the content of calcium in the rain is notably higher in karst areas, that is over 5 mg/l (or 12.5 mg CaCO 3 /l) higher than in non-karst areas, where it is below 0.1 mg/l. We took the first samples and made the first measurements of rain in Shilin stone kitkras1.p65 3.12.98,3:44 68 Black 69 1 Janja Kogovek Rock Dissolution in Stone Forests forest in July 1996. A total of 87 mm of rain fell from July 9 th to 14 th . The atmosphere was well washed on the evening of July 16 th , when it started to rain again. We estimated that approximately 10 mm of rain fell be- fore midnight, and by our measurements an additional 42 mm during the period from midnight to morning, which was when we took the first rain sample. The rain contin- ued occasionally throughout the day and added up to 14 mm, which was when we took the second sample. Our measurements were in correspondence with those from Dakenyan precipitation station, according to their data 56.6 mm of rain fell on July 16 th and 11mm on July 17 th , giving alto- gether 67.6 mm. Light rain fell for the next time on the night between July 20 th and 21 st in the form of a slow drizzle. We measured 3.5 mm in Shilin stone forest, the Dakenyan station measured 5.5 mm. Somewhat more rain fell the following night, we measured 10 mm, and the Dakenyan station 26.5 mm. Observ- ing the water table level while taking sam- ples the following day confirmed to us that in Dakenyan, which is located at a distance of seven kilometres and at Shilin stone for- est NE area more rain had fallen due to oc- casional local differences. In all cases we took samples of rain from the time when it began to rain until it stopped. This way I analysed the com- posite rain samples. The results of the measurements are presented in Table 1.6.1. The atmospheric temperature during the day and during the night altered only slightly around the value of 20 C. The SEC of the samples was in reciprocal propor- tion to the amount of rain. This seems logi- cal due to the fact that air pollution was washed from the atmosphere by light or heavy rain and smaller or larger dilution effects were caused. When the SEC and pH values were low (on the night between July 21 st and 22 nd ) the rain contained only 0.12 meq/l (6 mg CaCO 3 /l) of calcium and magnesium. During the drizzle on July 20 th , we measured a slightly higher SEC and pH, which leads us to conclude that the value of carbonates was probably also higher at that time. On our next visit on September 25 th 1997 there was drizzle, so that only 7 mm of rain fell during the day. The rainfall was heavier in the afternoon, and continued at intervals throughout the next day. The tem- peratures dropped sharply, we measured only 14 C. 25 mm of rain had fallen in all, and we analysed it (Table 1.6.1.). The rain contained 0.2 meq/l of calcium and magne- sium (10 mg CaCO 3 /l). It rained for the fol- lowing two days with occasional interrup- tions, during this period 10 mm of rain fell containing 14 mg CaCO 3 /l. Measurements and analyses of precipi- tation in Postojna in the period from 1985 to 1987 indicated a variation of the SEC be- tween 10 and 285 S/cm, the average value being 45 S/cm. Rain with a higher SEC, containing more calcium and carbonates, also had higher pH values. We assigned this to the Borea wind, that is to the dissolution of carbonate particles in the air. The aver- age values of the sum of calcium and mag- nesium in the rain was 6.8 mg CaCO 3 /l and the average pH 4.5. We occasionally re- corded noticeably higher values of sul- phates, nitrates and chlorides (Kogovek & Kranjc 1988). Table 1.6.1. The characteristics of rain in Shilin stone forest. Time of sampling Quantity of rain T SEC pH Carbonates Ca+Mg mm o C S/cm meq/l meq/l 16.-17.7.96 42 19.5 29 7.15 0.12 0.06 17.7.96 14 18.5 44 7.95 20.-21.7.96 3.5 20.5 76 8.24 21.-22.7.96 10 19.0 44 7.18 0.12 25.-26.9.97 25 14.0 17 7.12 0.12 0.20 26.-28.9.97 10 20.5 7.72 0.28 kitkras1.p65 3.12.98,3:44 69 Black 70 1 Carbonate rock dissolution in Shilin stone forest HabiŁ (1980) compares Shilin stone for- est to the rilled surface of the Dinaric karst except that in Stone forest it exists in a larger scale. The rilled weathered surface is formed in thick-layered gently sloping Early Permian limestone, shaped by rainwa- ter as well as its lithological composition, and the layers and fractures in the rock. Karst water is near the surface and thus floods part of the area between the rock ceilings. The lower parts of columns be- come dissolved to a higher degree because they come into contact with soil, and this type of corrosion probably took place be- neath an argilliferous cover. The dissolution of columns in Shilin stone forest is most in- tense in the more exposed areas, where the rainwater is channelled. Some light-col- oured, yellow-brown areas that remained untouched by the rainwater are noticeable. Song Linhua (1986) describes the com- position of the Shilin stone forest limestone with the maximum thickness of the layer being 30 m, and the main conditions for the development of stone forests. These are thick and pure limestone, an only slight sloping of the layer (maximum 15), a web of vertical fractures, a non-homogeneous cover of soil, and soil that is damp and has a high CO 2 content. Yuan Daoxian (1991) described some general characteristics of limestone and dolomite in Yunnan. For the area of Kun- ming, he established a lower aridness index due to the fact that more rainfall combined with high temperatures and CO 2 content in the soil causes increased limestone dissolu- tion. The speed of dissolution of limestone covered by soil is twice as fast compared to the rock above the surface that is not cov- ered by soil. The measurements we made in Stone Forest confirm this. Thickening of small solution basins or dishes-kamenitzas M.M. Sweeting (1995) described small solution basins or dishes-kamenitzas on the surface in Shilin stone forest, up to 1 m long and deep, and still deepening. During our visit to Shilin stone forest in July, I noticed that the small solution basins and dishes-kamenitzas were filled up to a different degree in the morning hours fol- lowing occasional drizzle overnight. The measurements of temperature, SEC and pH of the water in them revealed to what de- gree the water dissolved the carbonate rock. Most of the small solution basins had fallen leaves and other dead vegetation at their bottom, and those near the tourist path also contained garbage, all of this ef- fecting dissolution. Some of the small so- lution basins were overgrown, the thin cover of soil and vegetation holding quite a lot of water, this also being a form of car- bonate dissolution in small solution basins. We took some successive samples for the chosen small solution basins A and B to es- tablish the dissolution of the rock in the given conditions. Solution basin A was not overgrown, it was 50 cm wide and only a few centimetres deep. During the second sampling the water was not as deep and the water was filled with tiny larvae. Solu- tion basin B was not overgrown, and was larger in length (over 1 m), and the depth of the deepest part was 25 cm. The results of the measurement are set out in Table 1.6.2. The highest dissolution, that is the high- est carbonate content measured in the so- lution water basins, was 2.84 meq/l, which adds up to 142 mg CaCO 3 /l, although most likely this is not the highest value. We meas- ured the value of 3.68 meq/l due to dissolu- tion on rock columns. After successive ob- servations of the solution basin B, we no- ticed a proportionate increase of the con- centration of dissolved rock (measure- ments of SEC) with the lowering of the wa- ter surface (Fig. 1.6.1.), when evaporation is present, causing concentrating of the so- lution also due to this effect. During a no- ticeable drop in temperatures in Autumn 1997, we measured a notably lower SEC, and this indicates the effect of temperature. We did not measure the humidity, although we assume that it was relatively high. The Figure 1.6.2. shows dependence between Janja Kogovek Rock Dissolution in Stone Forests kitkras1.p65 3.12.98,3:44 70 Black 72 1 Dissolution of rock columns in Shilin stone forest During rainfall the precipitation water falls on up to 40 m high bare columns, trick- les down them and is accumulated at their base on argilliferous soil (Fig. 1.6.4.). As the rain comes into contact with the rock, it begins to dissolve it. During the rainfall on July 21 st and 22 nd 1996 I managed to take a few samples of this water and analyse it. On the night between July 20 th and 21 st 1996 only 3.5 mm of rain fell in the form of drizzle. The water trickled slowly down the columns, causing the rate of dissolution (the amount of dissolved limestone in a cer- tain quantity of rainwater) to be higher than that measured the following night during which the rain was more intensive and amounted to 10 mm of rainfall. Early in the morning of July 21 st I took a sample of wa- ter in the pool formed beneath a 15 m block point G. On July 22 nd I took a sample be- neath the 7 m high block at point H. For comparison I took a sample of water drip- ping directly from the block (H*), but it did Janja Kogovek Rock Dissolution in Stone Forests Fig. 1.6.3. Solution basins in Shilin stone forest. (Photo J. Kogovek) Fig. 1.6.4. Rock columns in Shilin stone forest. (Photo J. Kogovek) kitkras1.p65 3.12.98,3:44 72 Black 73 1 not differ from the one in the pool at its base. The characteristics of the rainwater have already been described. All the meas- urements and analyses made at the bases of blocks G and H are presented in Table 1.6.3. The non-carbonate hardness was 7% in all cases. The content of dissolved carbonates as well as the total hardness are proportion- ate to the SEC. The content of magnesium is low, below 0.1 meq/l. During the drizzle each litre of water on the 15 m high block (point G) dissolved 190 mg of CaCO 3 (3.8 meq/l), and during heavier rainfall only 105 mg CaCO 3 (2.1 meq/l). We presumed that the drizzle contained 6 mg CaCO 3 , as this was the value obtained by measurements the following night. In half the distance at point H 106 mg CaCO 3 /l (2.12 meq/l) was dissolved. This means that 1 litre of rain dissolved one fourth less limestone than at point G. The proportion of dissolved limestone in one litre of water taken from the base of the block was over 25% higher than during heavy rainfall. However, the estimation of the dissolution effect in heavy rainfall based on these measurements is, due to the almost three times greater amount of rainwater, over two times higher. Similar to the situation for dissolution elsewhere in karst landscapes, we estab- lished that dissolution of carbonate rock depends primarily on the amount of water. Gams (1980) and HabiŁ (1968) studied the interdependence of mass and volume dis- charge for karst flows in the Slovenian karst. Flow in the vadose zone (Kogovek 1986) indicated a linear correlation between dis- solved and removed carbonates and the volume of the water in the flow, that is from precipitation. Stone block dissolution after the re- moval of soil and vegetation in Shilin stone forest depends on factors such as the amount of rainfall, rain composition and temperature, and rain intensity, which af- fects the thickness of the water film on the carbonate blocks. The amount of limestone a certain amount of water will dissolve when it trickles down the block depends on the height of the block and/or the length of the path of the water, because the bal- ance is not usually present when the water reaches the base of the block. We can expect stronger dissolution ef- fects during slow, light precipitation since the rate of dissolution reaches higher val- ues. A high rate of dissolution is thus added Janja Kogovek Rock Dissolution in Stone Forests Table 1.6.3. Measurements of stone block dissolution taken at their base at points G and H. Place Length Precipitations Temperature SEC pH Carbonates Ca+Mg Delta SEC m mm C S/cm meq/l meq/l S/cm G 15 3.5 19.2 428 8.02 3.68 3.92 352 10 19.9 325 7.83 2.84 3.04 281 25 14.5 271 7.8 1.68 2.31 254 H 7 10 18.8 232 8.44 2.08 2.24 188 H 25 12.1 186 8.52 1.82 1.92 169 H* 7 10 19.1 230 8.56 2.00 2.24 186 Fig. 1.6.5. Dissolution of columns in stone forest (Points G and H): SEC is proportionate to the content of carbonates and/or to the total hardness. kitkras1.p65 3.12.98,3:44 73 Black 74 1 to the determining influence of the amount of precipitation on limestone dissolution. Fig. 1.6.5. presents the constant and low non-carbonate hardness and linear correla- tion of SEC and carbonate and/or total hard- ness, without additional influence of veg- etation and soil that could increase the ef- fects of dissolution, although these prob- ably affect only dissolution on soil-covered limestone. Characteristics of percolated water in caves Precipitation water percolates first through a thin or thick layer of soil with vegetation. If this is absent, it percolates directly through variously thick carbonate rock and appears in the form of percolated water in caves. All that takes place on the way to the cave is reflected in the composi- tion of groundwater in the cave. Carbonate rock dissolution is affected, aside from the composition and amount of rain, by the soil cover with its vegetation. To understand the influence of the soil cover, we took samples of the soil on the surface and determined the content of car- bonates, organic carbon, and phosphates (Table 1.6.4.). To determine which compo- nents of precipitation can be rinsed from the soil, we occasionally soaked the ground samples into distillated water (5g in 500 ml for six days) and after spinning them, we determined the content of the following in the water solution: chlorides, nitrates, sul- phates, silica, calcium, magnesium and pH. The results are presented in Table 1.6.5. During our visit to the Baiyun, Xin- shidong, Wayao and Jiuxiang caves in Yunnan, we took a number of samples of groundwater, carried out measurements of temperature, pH and SEC and some other analyses (Fig. 1.6.6.), which indicate basic groundwater characteristics in this part of the Chinese karst. Yuan Daoxian (1991) established the carbonate hardness of groundwater in the Muyuanfu cave (Guilin) between 1.6 and 5.7 meq/l (100 - 350 mg HCO 3 - /l), however we were not able to obtain any figures for Yunnan to verify our measurements. Baiyun Cave The Baiyun Cave is located in the Naigu stone forest. Ford et al. (1997) established that the basis of the Naigu stone forest is homogeneous grey limestone. Overlying it is a layer of approximately 1.5 m of medium layered massive dolomite limestone. Be- cause the groundwater also reflects the composition of the rock through which it percolates, the chemical analyses of carbon- ate, calcium and magnesium content car- ried out outline the type of rock. Percolation water The ceiling in Baiyun cave is only a few meters high, yet it is several tens of meters thick. The cave is well encrusted due to numerous and small-scale drips, and in some places there are smaller trickles of per- colated water. From the cave entrance to its end, a clear stream runs parallel to the tourist path. We visited the cave on July 18 th Table 1.6.5. Some components of soil soluble in water. Table 1.6.4. Soil analyses. Sample Carbonates Organic C P 2 O 5 % g/100g mg/100g Stone forest 0 0.39 24 P1- near Maoshuidong 1.08 1.7 48 P2 - near Guanyindong 0.8 1.4 28 Sample pH Calcium Magnesium Silica Chlorides Nitrates Phosphates mg/100g mg/100g mg/100g mg/100g mg/100g mg/100g Stone forest 6.65 50 3.6 170 5 9 1 P1- near Maoshuidong 6.3 20 1.2 78 5 2.2 0.2 P2 - near Guanyindong 8 8 2.4 99 5 11 0.4 Janja Kogovek Rock Dissolution in Stone Forests kitkras1.p65 3.12.98,3:44 74 Black 75 1 Janja Kogovek Rock Dissolution in Stone Forests Fig. 1.6.6. Water samples analysis. (Photo J. Kogovek) Fig. 1.6.7. Sampling of percolation water at Point G in Baiyun cave. (Photo M. Knez) kitkras1.p65 3.12.98,3:44 75 Black 76 1 1996, following two days of heavy rainfall which caused heavier discharge. A sample of the percolation water G-96 was taken Janja Kogovek Rock Dissolution in Stone Forests from the ceiling (Fig. 1.6.7.). The discharge of this tiny trickle amounted to 100 ml/min. The water travelled a little less than 1 m Fig. 1.6.9. Calcium and magnesium in percolation water. Fig. 1.6.8. Total hardness and SEC of percolation water. Table 1.6.6. The characteristics of percolation water in Jiuxiang, Baiyun, Xinshidong and Wayao caves. Cave Place Dischar. T SEC pH Carbonat. Ca Mg Total h. Ca/Mg Noncar.h. ml/min C S/cm meq/l meq/l meq/l meq/l meq/l Jiuxiang A - 97 331 8.40 3.36 1.28 2.07 3.35 0.6 B - 96 70 20.0 605 8.40 5.12 2.72 2.88 5.60 0.9 0.48 B - 97 17.2 500 8.15 4.75 2.47 2.44 4.91 1.0 0.16 C - 97 100 15.9 615 8.03 5.28 3.19 4.15 7.34 0.8 1.06 D - 97 692 7.68 7.70 3.47 4.27 7.74 0.8 E - 96 17.5 514 7.80 5.04 2.80 2.80 5.60 1.0 0.56 E - 97 15.9 556 7.70 5.75 3.35 2.99 6.34 1.1 0.59 F - 97 15.2 394 8.40 4.21 1.88 1.62 4.39 1.2 0.18 Baiyun G -96 100 17.3 550 7.75 6.08 6.16 0.08 G - 97 50 17.6 594 7.44 6.32 5.35 1.19 6.54 5.5 0.22 H - 97 10 645 8.03 7.05 5.75 1.67 7.42 3.4 0.37 I - 96 400 18.0 590 7.15 6.52 6.68 0.16 I - 97 50 16.4 527 7.97 5.43 4.27 1.36 5.63 3.1 0.2 J - 97 100 16.4 532 7.88 5.63 4.47 1.59 6.06 2.8 0.43 K - 97 398 4.54 2.63 2.16 4.79 1.2 L - 97 16.8 511 7.63 5.59 4.63 0.88 5.51 5.3 Xinshidong M 3 20.4 405 8.45 4.00 4.24 0.24 N 20 478 8.15 4.88 5.20 0.32 O 10 515 8.40 5.52 P 80 19.8 545 7.53 5.76 6.00 0.24 R 18.6 470 7.52 5.12 Wayao S 16.2 355 8.27 2.75 3.31 0.2 3.51 0.76 T 15.9 461 8.11 3.77 4.59 0.16 4.75 0.98 kitkras1.p65 3.12.98,3:44 76 Black 77 1 Janja Kogovek Rock Dissolution in Stone Forests through the air and then fell onto an en- crusted dripstone beside the tourist path, where evidence of flowstone deposition was noticeable. Characteristics of percola- tion water are presented in Table 1.6.6. and Figs. 1.6.8., 1.6.9. During our visit in September 1997, as we recorded smaller discharge of percola- tion water along the cavern than in July 1996, we took a sample of the spurt G (G- 97) again. It resulted in higher values of SEC and hardness, which is probably the reflec- tion of the nature and lower discharge speed through the cavern ceiling. The ratio between the carbonate and magnesium content was 5.5. Only a few meters away we sampled dripping H-97 with the high- est SEC and hardness of the percolation water in the cave. The carbonate hardness was 7.05 meq/l, the total hardness was 7.42 meq/l. The ratio between the carbonate and magnesium content was lower in compari- son with trickle G, which indicates a higher proportion of magnesium dissolution when compared to calcium. Flowstone gours In July 1996 we took a sample of trickle I-96 located somewhat deeper in the cave, with the discharge of 400 ml/min. It dripped into a gour, then the water succes- sively spilled over into some lower lying gours. SEC measurements indicated a nota- ble decrease in values, and from this we concluded that there was a noticeable depo- sition of carbonates, that is growth of gours. In the next gour the SEC decreased by 13%, to the third by an additional 11%, and to the fourth by another 11%. So, in the distance of a few meters the SEC decreased by a whole 35%. Because there were no visible possible polluters above the cave, we con- cluded that the changes of the SEC are pro- portionate to the carbonate content. This assumption could, of course, be confirmed only by parallel analyses. This percolation water had the highest values for carbonate content (6.25 meq/l) and highest total hard- ness (6.68 meq/l) of all our measurements of percolation water made in July 1996 in Fig. 1.6.10. Small gours in Baiyun cave - Point K. (Photo T. Slabe) kitkras1.p65 3.12.98,3:49 77 Black 78 1 Janja Kogovek Rock Dissolution in Stone Forests this area of the Yunnan karst. The non-car- bonate hardness was very low, but we were unfortunately not able to determine the calcium content due to lack of adequate equipment. In September 1997 this trickle was drip- ping slowly, and the gours were only par- tially filled with water, running from the stream, so we sampled the water of 1 me- ter distanced dripping with the discharge of approximately 50 ml/min I-97, which had a lower SEC value and lower hardness than I-96. We sampled a 3 m distanced tiny spurt with a discharge of 100 ml/min and some- what higher hardness than the dripping I- 97. We conclude that they were the reflec- tion of a different type of percolation. Both trickles had a lower calcium/magnesium ratio, similar to the trickle H. In September 1997 we took samples of water in smaller gours in the beginning of the cave at point K (Fig. 1.6.10.). Through successive gours the SEC gradually de- creased from the first to the fourth gour, in total by 61 S/cm. During this time, 56 mg CaCO 3 from 1 liter of water were de- posited (Fig.1.6.11.). However, the carbon- ate content of the inflow water (4.54 meq/ l) was relatively low, as the inflow water into the gours at point I, I o -96 reached the value of 6.52 meq/l (Table 1.6.7.), and the inflow into the large gour in Jiuxiang cave (D-97) even 7.7 meq/l (Table 1.6.6.). Stream All percolation water in Baiyun cave was oversaturated and everywhere visible signs of fresh flowstone deposition due to the trickling of water were noticeable. The stream (L), which accompanies visitors alongside the tourist path from the begin- ning to the end of the cave, also has a high content of carbonates and calcium. The Table 1.6.7. Flowstone deposition in the gours in Baiyun cave and in small gours in Jiuxiang cave (E). Cave Place Dischar. T SEC pH Carbonate Ca Mg Total h. Ca/Mg Noncar. ml/min C S/cm meq/l meq/l meq/l meq/l meq/l Jiuxiang Eo - 96 17.5 514 7.80 5.04 2.80 2.80 5.60 1.0 Ea - 96 17.8 489 Eb - 96 17.8 488 Ec - 96 18.0 472 Eo - 97 15.9 556 7.70 5.75 3.35 2.99 6.34 1.1 0.59 Eb - 97 15.7 477 8.24 4.9 2.35 2.84 5.19 0.8 0.29 Baiyun Io - 96 100 18.0 590 7.15 6.52 6.68 Ia - 96 515 Ib - 96 450 Ic - 96 385 Ko - 97 398 4.54 2.63 2.16 4.79 1.2 Ka - 97 385 Kb - 97 375 Kc - 97 337 3.65 2.07 1.6 3.67 1.3 Fig. 1.6.11. Flowstone deposition in the gours in Baiyun cave and in small gours in Jiuxiang cave. kitkras1.p65 3.12.98,3:49 78 Black 79 1 Janja Kogovek Rock Dissolution in Stone Forests content of magnesium is somewhat lower. The calcium/magnesium ratio is 5.3. The water does not contain solid soil cover par- ticles, as was already established for other flows. I conclude that the stream is a heavier trickle of the discharge of percolation wa- ter. Its water is oversaturated and deposits flowstone, the SEC decreasing by 25 S/cm over a distance of some 400 m through the cave. The cave managers appropriately led this water to the nearby stalagmite and into the flowstone gours at point I, which both remain without fresh water flow during the dry season. But they probably did not verify the content of the water beforehand. Al- ready on the three meter distance to the sta- lagmite the SEC decreases by 42 S/cm, which means relatively rapid flowstone deposition. The highest carbonate content in per- colation water in the area of Slovenia was recorded in Karst caves, in kocjanske jame cave as 6.3 meq/l and in Vilenica cave as 6.6 meq/l, though for dripping with discharge of just a few ml/min (Kogovek 1984). Xinshidong and Wayao caves We explored Xinshidong cave, which is not open for tourists, located in Naigu stone forest on July 22 nd . The surface above the cave Xinshidong is covered with a thin layer of soil and vis- ible rocks grown over with grass and thin bushes. The height of the cave ceiling is only to a few meters, and we noticed visible signs of the water level occasionally almost reach- ing it. Numerous small drips in the cave were probably caused by the heavy rainfall the previous night. The cave is located near the surface, as the ceiling is only 2 m thick at the entrance and approximately 10 m thick further into the cave. We noticed numerous tiny drips with the discharge of a few ml/min and only a few larger ones. The largest discharge, 80 ml/min, came from the trickle P located in the deepest part of the cave (near Point 10 on Fig. 1.2.10.). Measurements and analyses indicated an increase of SEC, dissolved car- bonate content and total hardness in the direction from the entrance towards the end of the cave, that is with the increase of the cave ceiling thickness (Table 1.6.6., Fig. 1.6.12.). This means that on the thin parts of the ceiling saturation and/or over- saturation of percolation water does not occur. Sample R (at Point 11) is water from a small lake in the lowest part of the cave, its characteristics reflect percolation water collecting on an impermeable bottom with fine sediments. Similar to the Jiuxiang and Baiyun caves, the percolation water also has a low non-carbonate hardness. Similar characteristics of percolation water were measured in the Wayao cave, which is located in the direct vicinity of a road, which is a source of pollution. The percolation water, percolating through an approximately 3 m thick ceiling (S) reached lower hardness values than deeper in the cave where the ceiling is around 8 m thick (T). In both samples we noticed a lower non-carbonate hardness than with other percolation water, a higher content of chlo- rides and sulphates (Table 1.6.6.). Chemical composition of all examined water in the area of Lunan Fig. 1.6.13. indicates the dependency of SEC and carbonate content and total hard- Fig. 1.6.12. Xinshidong cave: total water hardness and SEC increase with cave ceiling thickness. kitkras1.p65 3.12.98,3:49 79 Black 80 1 Janja Kogovek Rock Dissolution in Stone Forests ness of all performed measurements, of the rainwater as well as of water in gours and trickling water on columns in Shilin stone forest, percolation water in caves and karst groundwater flows. There is a linear corre- lation between SEC and total hardness and carbonate content, even though dolomite water with a Ca/Mg ratio of 0.8 and water with a Ca/Mg ration of 18 are present. The percolation water in the larger chamber in Juxiang cave, which we assume is polluted, stands out. A somewhat larger difference between the total and carbonate hardness (non-carbonate hardness) was found for the groundwater flow at Point a to the spring of Dalongtan - 5. Conclusive findings Rainfall observation in the Shilin stone forest area in Yunnan showed that a large amount of precipitation may fall in a rela- tively intensive form (July 1997, 40 mm in 6 hours) or a slow rain, with the daily amount below 10 mm. The specific electric conductivity of the rainwater amounts from 17 to 76 S/cm, pH from 7.1 to 8.25, the total calcium and magnesium content ranged from 3 to 24 mg CaCO 3 /l. Yuan Daoxian (1991) states that the calcium con- tent in rainwater in the Chinese karst is notably higher than in non-karst areas and exceeds 12.5 mg CaCO 3 /l. The soil cover, Fig. 1.6.13. Carbonate content and total hardness in dependance of the SEC in rainwater, in gours and at the base of columns in Shilin stone forest, in percolation water in the aforemen- tioned caves and in groundwater flow. Carbonates, total hardness (meq/l) kitkras1.p65 3.12.98,3:49 80 Black 81 1 Janja Kogovek Rock Dissolution in Stone Forests that is non-soluble components in it that can be rinsed by rain, contribute signifi- cantly to carbonate rock dissolution on overgrown karst. These are primarily sili- cates, nitrates and chlorides. We sampled the percolation water (to- gether 25 samples) in four caves in July and September in various hydrological condi- tions. Percolation water in the Jiuxiang cave reached the ratio of Ca/Mg from 0.6 to 1.2, similar to the Mai Tian river which submerges into it. The specific electric conductivity, which reflects the amount of dissolved substances, ranged from 331 to 692 S/cm, the carbonate content was 3.36 to 7.7 meq/l and total hardness from 3.35 to7.74 meq/l. The highest hardness value was recorded in percolation water filling the large gours in Jiuxiang cave in Septem- ber in the period of high water levels. A higher value of magnesium in comparison with calcium was measured in it, which is something we have never measured in the Slovenian karst. Due to the fact that perco- lation water reaches its highest hardness values in the beginning of the season, simi- lar to the spring water in this karst, we as- sume that we would have recorded addi- tionally higher values if measurement was carried out in that period. It is interesting that the water inflow to the gours in kocjanske jame cave has the highest hardness of all water in the cave, that this flow is occasional and oc- curs only after precipitation, that it is abun- dant, and of long duration. However, the water in kocjanske jame cave has low magnesium content, and the hardness is approximately 15% lower compared to the water that flows to the large gours in the Jiuxiang cave. The percolation water in Baiyun cave reflects a different rock composition than Jiuxiang cave the Ca/Mg ratio value ranges from 2.8 to 5.5. The water is oversaturated and deposits flowstone. In September 1997 discharges were lower than in July 1996. In September we measured higher values of hardness and specific electrical conduc- tivity at point of comparison G. This prob- ably reflects the predominance of the man- ner of percolation in conditions of the less filled trickle hinterland in comparison with seasonal variations. The seasonal variation of hardness could be verified only by more frequent measurements throughout the year. In Xinshidong cave we sampled wa- ter that had percolated through the 2 to ap- proximately 10 m thick cave ceiling. Meas- urements confirmed the increase of hard- ness, that is the various rates of saturation or oversaturation of the water as proportion- ate to the increase of the ceiling thickness. The measurements of flowstone depo- sition in gours in the Jiuxiang and Baiyun caves indicated that in the short distance through a few gours of approximately 3 m, 20% (56 mg CaCO 3 ) to 35% of the total car- bonates is deposed from one litre of perco- lated water. The stream that runs through Baiyun cave also deposits flowstone, and is classified into percolation water in regard to its chemical composition. This is also the reason it is being used to fill gours and a nearby stalagmite, which both have a low inflow of percolation water. This is not pos- sible in the case of the Mai Tian river in the Jiuxiang cave. kitkras1.p65 3.12.98,3:49 81 Black 82 1 Evaluation of the basic hydrological characteristics of the wider area of Tian- shengan village in the north-eastern part of Lunan province was programmed as the basis for planning the tracing experiment, which was to give more accurate answers to questions concerning the groundwater flow regime in studied karst aquifer. The existing data concerning the hydrological conditions were completed by new obser- 1.7. HYDROLOGICAL CHARACTERISTICS OF THE TIANSHENGAN AREA Metka PetriŁ vations in the field and analysis of precipi- tation measurement data and groundwater discharge. Hydrological conditions The hydrological scheme of the dis- cussed area includes surface streams and lakes, large and small karst springs, and Metka PetriŁ Hydrological Characteristics of the Tianshengan ... Fig. 1.7.1. Hydrological map of the Tianshengan area (a-lake, b-surface stream, c-bigger spring, d-smaller spring, e-shaft with underground water flow, f-village, g-mark of the hydrological object - see also chapter 1.9.). kitkras1.p65 3.12.98,3:49 82 Black 83 1 Metka PetriŁ Hydrological Characteristics of the Tianshengan ... groundwater streams (Figs. 1.7.1., 1.7.2.). The most important spring is Dalongtan at 1810 m above sea level with an estimated discharge from 0.24 to 4.6 m 3 /s (verbal ac- count). Approximately 4 and 5 km to the south-east on the eastern part of the aqui- fer there are another two interesting springs: Changshuitang (marked as 9) 1866 m above sea level, and Xiniutang (marked as 10) 1863 m above sea level. During the time of our field research, it was not possi- ble to evaluate discharge of the first spring as the water flows directly into a lake. The other one was evaluated during various hydrological conditions as 100 l/s to 1 m 3 / s. These values are not valid in extreme hy- drological conditions, but for a shorter pe- riod of a medium water table level in July 1996. We have no data for discharge of other springs. In the recharge area of Dalongtan, groundwater discharge is measured at the Dakenyan hydrological station located in a vertical shaft around 2.5 km north-east of the spring. The data for the period of Au- gust 1993 to August 1996 show discharges ranging from 12 l/s to 6.28 m 3 /s. Fig. 1.7.2. Relief map of the tracing test area (legend on Fig. 1.7.1.). Fig. 1.7.3. Bajiang river before Dadieshui waterfall. (Photo J. Kogovek) kitkras1.p65 3.12.98,3:49 83 Black 84 1 Fig. 1.7.4. Dadieshui waterfall. (Photo J. Kogovek) Fig. 1.7.5. Pumping station. (Photo A. Mihevc) The surface stream which is formed by water from the Dalongtan spring, flows into Bajiang river (Fig. 1.7.3.). It runs over the more than 90 m high Dadieshui tufa water- fall (Fig. 1.7.4.). Bajiang river is one of the influxes of Nanpanjiang river and repre- sents the erosion base of the discussed area. Also the water from other karst springs in the western part of the territory charge sur- face flows, which head towards the south or south-east and flow to Bajiang river. There are no surface flows in the eastern part. Numerous lakes play a special role. As the whole area of study is cultivated, with rice, tobacco and corn fields predominat- ing, the lakes are important primarily for the irrigation of agricultural land. The lakes have formed both as a natural accumulation of karst water and artificially by damming surface flows. Groundwater is also used for irrigation. Pumps for supplying water to the irrigation systems are located in seven vertical shafts cutting the groundwater flow, although usually only three stations are active (Fig. 1.7.5.). All seven operate only at the end of Metka PetriŁ Hydrological Characteristics of the Tianshengan ... kitkras1.p65 3.12.98,3:49 84 Black 85 1 the dry season, when a large amount of water is needed for irrigating rice fields. The largest pump has the capacity of 50 l/s, the smallest 2.5 l/s. The pumped water is stored in open or closed reservoirs in higher locations, then the water is led by the force of gravity through channels to the lower-lying fields (Fig. 1.7.6.). The source of recharge of the karst sys- tem is precipitation, with its distribution in wet and dry seasons. For the area of the high karst plateau of east Yunnan the av- erage annual precipitation in the period 1980-1992 was 796 mm, of this 80% to 88% in the wet season. For the smaller area of the village of Tianshengan data are available for daily precipitation for the period of three years, from August 1993 to August 1996, measured at the precipi- tation station located in Dakenyan. The annual precipitation in 1994 and 1995 was 1133 mm and 727 mm. The charac- teristics of precipitation are discussed in detail later. Fig. 1.7.6. Reservoir and irrigation channels. (Photo J. Kogovek) Hydrological analysis of measured values of daily precipitation and discharge In the wider area of Tianshengan village the hydrological parameters are regularly measured at the Dakenyan station (Fig. 1.7.7.). In the vertical shaft, which cuts through the main groundwater flow ap- proximately 2.5 km north-east of Dalongtan spring, there is a pump and nearby the gaug- ing profile for underground discharge measurements which began to operate in August 1993. Discharges are measured four times daily. The procedure is such that the measurer reads the water level in profile off a measuring staff. Based on these figures he calculates the discharge from a pre-made discharge curve. The average daily value is obtained as the average of four measure- ments (at 6.00, 12.00, 18.00 and 24.00). At the location of Dakenyan, precipitation is also measured with a rain gauge once daily at 8 a.m. There are no data on the quality of Metka PetriŁ Hydrological Characteristics of the Tianshengan ... kitkras1.p65 3.12.98,3:50 85 Black 86 1 measurement instruments and accuracy of measurements, which is why an estimate of measurement error is not possible. In the further analysis, data supplied by the meas- urement stations were used. The daily data on discharge and precipi- tation for the period of three years from August 1 st 1993 to August 21 st 1996 were collected (Fig. 1.7.8.). The division into wet and dry seasons is clear for discharge and precipitation. The wet season begins in May and ends in October, the rest of the year is the dry season. This distribution is repeated through the entire observation interval. Each wet - dry cycle lasts approximately one year. Precipitation of varying duration and intensity also occurs during the dry season, but during this time discharge in under- ground channels does not increase signifi- cantly. There is interesting data for the day of December 2 nd 1994, when despite the daily precipitation quantity of 59 mm be- ing the second largest measured, the dis- charge measured at Dakenyan station prac- tically did not increase. We can say that be- side the quantity and intensity of precipita- tion, the distribution of precipitation in time is a significant influence on the dis- charge curve. The periods of high waters are short, the attained maximum is followed by a steep decrease and a longer period of middle and low waters. With the exception of extreme values, discharge is less the 2 m 3 /s. During the wet season, precipitation occurs in in- tervals of 1 to 3 days (exceptionally longer), and the periods without rainfall in between are 1 to 9 days long. The effect of pumping on discharge is not noticeable due to small capacities and occasional operation of in- dividual pump stations. Extremely dry pe- riods in the time when all seven stations are operating to irrigate fields are the excep- tion. The characteristic values of precipita- tion are presented in Table 1.7.1. for the observation period from August 1 st 1993 to August 21 st 1996. We can present the total annual value for this interval only for 1994 and 1995, but already these data point to a Fig. 1.7.7. Dakenyan measurement station. (Photo T. Slabe) Metka PetriŁ Hydrological Characteristics of the Tianshengan ... kitkras1.p65 3.12.98,3:50 86 Black 87 1 high variation of annual precipitation quan- tities, between 1133 and 727 mm. The maxi- mum daily precipitation was 72 mm, meas- ured in July 1994. The whole observation period was 1117 days long, and of these 902 days were without rainfall (283 days in 1994, and 301 days in 1995). Discharge characteristics are described in the second part of the table. The value of 12 l/s is recorded as the minimal value. But there are some difficulties connected to measuring this parameter. The total quan- tity of pumped water from underground flow is, during extremely dry conditions, practically equal to discharge and there is Table 1.7.1. Characteristic values of precipitation and discharges Precipitation P annual P mean P max days with (mm) (mm) (mm) P=0 mm 1993-1996 2.4 75 902 1994 1133 3.1 75 283 1995 727 2.0 46 301 Discharges Q min Q mean Q max (m 3 /s) (m 3 /s) (m 3 /s) 1993-1996 0.012 0.47 6.28 1994 0.012 0.45 3.48 1995 0.012 0.42 6.28 Fig. 1.7.8. Diagram of daily precipitation and discharge for the period of 1.8.1993 to 21.8.1996. no water in the measurement profile at Dakenyan station. Discharges for this pe- riod are thus an estimation based on the quantity of pumped water. Determining the minimal value of 12 l/s is thus somewhat questionable and represents merely an ap- proximate estimation. During the highest water table level in October 1995, 6.28 m 3 of water per second flowed through the measurement profile. The discharge peak does not correspond in time to the precipi- tation peak, which was recorded in July 1994. A similar discordance can be noticed in comparing average recorded daily dis- charges and daily precipitation. The second parameter is not usually used to describe the characteristics of the time function of precipitation and is adopted here only be- cause it makes comparing precipitation and discharge in the entire observation period possible. This comparison shows the aver- age daily precipitation value in the period of August 1 st 1993 to August 21 st 1996 to be in between the value for 1994 and 1995. The mean discharge is higher in the entire observation interval than in both singular years. Again, it can be concluded that be- side the quantity and intensity of precipita- Metka PetriŁ Hydrological Characteristics of the Tianshengan ... kitkras1.p65 3.12.98,3:50 87 Black 88 1 tion, the distribution and consequently the state of water reserves in the karst aquifer has an important effect on groundwater dis- charge in subterranean channels. To determine the interdependency of precipitation and discharge, I calculated the cross-correlogram of both time functions (Fig. 1.7.9.) with the Stochastos program by A. Mangin and D. DHulst (Mangin 1984). The calculations confirmed that the corre- lation coefficient is not high, reaching the maximum value 0.55 while taking into ac- count the one-day retardation of the reac- tion of discharge to precipitation. The curve has a pointed form with a rapid dip of the correlation in the first days, then the curve slope decreases. The pointed form in the beginning indicates the existence of karst channels, which rapidly drain infiltrated precipitation. The decline of the curve slope in the second part points to the con- servation of precipitation information over a longer period of time and a slower func- tion of percolation through the fissure net- work. Particularly are examined the character- istics of two hydrological years from May 1 st 1994 to May 16 th 1996. The hydrological years in the observed climatic conditions have a characteristic shape, which is peri- odically repeated in the wet season - dry season system (Fig.1.7.8.). The values of the comparison between annual precipitation and mean discharges for two hydrological years with special emphasis on the relations between dry and wet seasons are presented in Table 1.7.2. Due to not having data concerning pre- cipitation and discharge in the previous period, I cannot compare the characteris- tics of the two studied hydrological years with averages of many years. Based on data for two years, large amplitudes of annual Table 1.7.2. Comparison between precipita- tion and discharge for two hydrological years. P (mm) Q mean (m 3 /s) 1.5.94 - 12.5.95 1125 0.48 13.5.95 - 16.5.96 760 0.38 wet season 1994 919 0.74 dry season 1994/95 196 0.30 wet season 1995 675 0.55 dry season 1995/96 95 0.18 Fig. 1.7.9. Cross-correlogram. Metka PetriŁ Hydrological Characteristics of the Tianshengan ... kitkras1.p65 3.12.98,3:52 88 Black 89 1 values of both parameters can be presup- posed. Following a relatively wet first year, the precipitation decreases by 32% and dis- charge by 21% the next year. I also compared the dry and wet seasons of both years and found large differences. The dry season of 1994/1995 had approxi- mately two times more precipitation as the dry season of 1995/1996, and the mean dis- charge was also approximately two times greater (0.30:0.18). The wet season of 1994 was significantly wetter than in 1995 (P=919:675 and Q=0.74:0.55). 1995 had marked discharge peaks, as the conse- quence of a less even precipitation distri- bution. Due to a relatively large amount of precipitation in the dry season in 1994/ 1995, the decrease in discharge is lesser in this period. Based on data concerning daily dis- charge and precipitation in the period of the two hydrological years from May 1 st 1994 to May 16 th 1996 two cumulative curves were also drawn. They present the total volume of water drained from the ba- sin, that is the total quantity of precipita- tion in the selected time interval (Fig. 1.7.10.). The distribution into dry and wet seasons is clearly visible from these curves. Inside of individual intervals the curve is relatively constant, and the curve incline is much greater for the wet than for the dry season. Conclusions A review of the basic hydrological char- acteristics of the Tianshengan area was con- ducted. The main drainage routes are sub- terranean channels near the surface. Groun- dwater runs toward karst springs, among which Dalongtan, located south-west of Beidacun village, is the most important. Based on daily precipitation measure- ments at Dakenyan station and discharge in the ganging site at the same station, some other basic hydrological analyses were car- ried out. I compared records of daily data for the whole interval of measurements from August 1 st 1993 to August 21 st 1996 and for the period of two hydrological years, from May 1 st 1994 to May 16 th 1996. For precipitation and discharge, the divi- Fig. 1.7.10. Cumulative curves of precipitation and discharge for the period of two hydrological years. Metka PetriŁ Hydrological Characteristics of the Tianshengan ... kitkras1.p65 3.12.98,3:52 89 Black 90 1 sion into the wet and dry season is clearly visible. The wet season begins in May and finishes in the end of October, while the rest of the year is the dry season. This dis- tribution is apparent also from the cumula- tive curves of precipitation and discharge. From the interval of two hydrological years, the mean annual quantity of precipi- tation was 942 mm, the minimum discharge 12 l/s, the mean discharge 0.47 m 3 /s and the maximum discharge 6.28 m 3 /s. We found a characteristic regime with a short duration of high discharge and longer periods of in- termediate and low waters. The effect of precipitation on discharge is obvious, al- though the connection depends on numer- ous factors, which should be more accurately determined in this next phases of research. Metka PetriŁ Hydrological Characteristics of the Tianshengan ... kitkras1.p65 3.12.98,3:52 90 Black 91 1 Janja Kogovek Physical and Chemical Characteristics Prior to performing the first tracing ex- periment in the Lunan area we analysed the accessible karst water flows in the larger Tianshengan area. While taking samples, we determined temperature, specific electric conductivity (SEC) and pH (Figs 1.8.1. and 1.8.2.) in the field, and later on in the labo- ratory the content of carbonates, calcium and magnesium by procedures described in 1.8. PHYSICAL AND CHEMICAL CHARACTERISTICS OF GROUNDWATER OF TIANSHENGAN AREA (The wider area of the tracing experiments) Janja Kogovek chapter 1.6. We attempted to determine the main characteristics of the water, and simi- larities and differences which would indi- cate possible directions of groundwater movement, as an aid in planning the trac- ing experiment. Water samples were taken from poten- tial injection Points a, b, c and d (Quig- huadong), in caves and in vertical shafts Fig. 1.8.1. Measurements of temperature, pH and SEC and water sampling. (Photo J. Kogovek) Fig. 1.8.2. Water sampling at Point 7. (Photo J. Kogovek) kitkras1.p65 3.12.98,3:52 91 Black 92 1 Janja Kogovek Physical and Chemical Characteristics Table 1.8.1. Measurements and analyses of all taken samples in the tracing area (H water table level (low, high, very high), T temperature, K- carbonate content, Ca+Mg total hardness, Ca calcium content). Place Date H T SEC pH Carbonates Ca+Mg Ca Ca/Mg C S/cm meq/l meq/l meq/l a 15.7.96 17.7 490 7.2 4.72 5.28 b 15.7.96 17.2 501 7.3 4.88 5.44 4.48 c 15.7.96 17.4 494 7.4 4.80 5.40 4.48 d 15.7.96 17.6 334 7.6 3.04 3.56 3.04 5.8 26.9.97 high 13.1 181 7.4 1.54 1.80 1.52 5.4 0 15.7.96 low 17.4 417 7.6 4.40 4.45 3.76 5.4 19.7.96 higher 18.4 362 7.4 23.7.96 higher 18.2 374 7.5 1 16.7.96 17.5 420 7.7 4.08 4.48 2 16.7.96 low 17.6 424 7.4 4.16 4.56 17.7.96 high 18.0 339 7.3 3.04 3.44 23.7.96 18.0 417 7.3 27.9.97 high 15.2 310 7.4 2.96 3.31 2.91 7.3 3 16.7.96 low 17.6 429 7.6 4.20 4.60 19.7.96 18.3 400 7.3 23.7.96 18.1 401 7.4 27.9.97 high 15.6 316 7.4 3.00 3.19 2.91 10.3 4 15.07.96 12 low 19.7 444 7.6 4.12 4.60 4.24 11.8 16.07.96 20 low 17.6 436 7.5 4.28 4.64 17.07.96 18 high 17.9 308 7.4 2.64 3.04 19.07.96 18 18.4 365 7.3 3.24 3.76 20.07.96 06 390 3.60 4.00 20.07.96 18 406 3.72 4.20 21.07.96 06 421 4.40 21.07.96 18 426 4.44 22.07.96 06 420 4.36 22.07.96 18 413 4.28 23.07.96 13 higher 378 7.3 25.09.97 00 17.6 390 7.4 3.77 3.99 3.71 10.6 5 17.7.96 higher 19.7 397 7.5 3.60 4.04 6 16.7.96 low 18.3 318 7.3 3.04 3.20 19.7.96 higher 19.8 309 7.3 26.9.97 high 14.8 200 7.6 1.82 1.96 1.80 11.3 7 16.7.96 18.0 300 7.4 2.72 3.04 19.7.96 18.5 305 7.3 8 16.7.96 17.4 434 7.5 4.12 4.52 9 17.7.96 low 17.9 477 7.0 4.68 4.96 19.7.96 high 18.0 400 7.0 23.7.96 17.9 418 7.1 27.9.97 17.7 417 7.2 4.25 4.51 4.27 18 10 17.7.96 high 18.9 215 7.4 2.04 2.08 19.7.96 20.5 335 7.2 21.7.96 19.6 362 7.2 3.60 3.84 23.7.96 19.1 368 7.3 27.9.97 higher 14.5 293 7.5 2.81 3.03 2.70 8.2 10a 21.7.96 20.7 355 7.6 3.60 3.84 between the injection point and the final spring of Dalongtan accessible water flow at points: 0 (Yanshidong), 1 (Maoshui- dong), 2 (Shihuiyao), 3 (Xiangshuidong), 4 (Dakenyan), 7 (Guan Yindong) and from springs 5 (Dalongtan), 9 (Changshuitang) kitkras1.p65 3.12.98,3:52 92 Black 93 1 Janja Kogovek Physical and Chemical Characteristics and 10 (Xiniutang) (Figs. 1.9.1., 1.7.1., 1.7.2.). On July 15 th and 16 th 1996 we took sam- ples during low water levels. Only at Point 9 was there also a low water table on July 17 th , which reached an estimated 50 l/s on July 19 th - the highest recorded during our observations. At Point 10 the highest dis- charge was on July 17 th , we estimated it to be 0.5 m 3 /s. On July 21 st it underwent a steep decrease. Sampling on July 17 th and 19 th took place during a high or very high water level in most sampling points. The water level was only estimated, due to the fact that measurements of discharge exist only for Point 4 Dakenyan. In September 1997 we repeated the sam- pling in the sampling Points 2, 3, 4, 6, 9 and 10. The water levels were high, at points 2, 3 and 6 even the highest among all the meas- urements and sampling during July 1996 and September 1997. Temperature In July 1996 the temperature measure- ments revealed a relatively constant tempera- ture during a low or medium water level, which was in the interval of 17.2 to 17.6 C from point a to Point 4. The pH was in the interval from 7.2 to 7.7. Only at Points 6, 7 and 8 we did measure somewhat higher tem- peratures. During a high water level follow- ing rainfall we measured some tenths of a degree higher temperatures at most sam- pling points (18 to 19 C), which reflect the influence of warmer precipitation at these points, as then the water does not cool off in such degree - due to faster movement un- derground - as it would in the case of slower movement and a lower water level. At spring 9 we did not record noticeable differences, while the temperature at spring 10 was 0.7 C lower, which might reflect the pressing out of older water (Tables 1.8.1., 1.8.2.). In September 1997 we found generally lower temperatures, from 13.1 to 17.7 C. Spring 9 had a temperature of 17.7 C, which is only 0.3 C less than at nearly the same water level in July 1996. Small varia- tions of temperature of this spring during the year point to longer water retention in the hinterland and strong moderation of precipitation effects. At Point 10 we meas- ured a temperature of only 14.5 C, which it is still necessary to verify. Otherwise, it is evident that the subterranean stream flow from Point d to Point 4 gradually becomes warmer. Table 1.8.2. Physical and chemical characteristics of groundwater in the wider tracing area during low and high water tables in July 1996 At low water level At higher water level Place T SEC pH Carb. Ca+Mg Ca Ca/Mg Noncarb. T SEC pH Carb. Ca+Mg a 17.7 490 7.2 4.72 5.28 0.56 b 17.2 500 7.3 4.88 5.44 4.48 4.7 0.56 c 17.4 494 7.4 4.80 5.40 4.48 5 0.60 d 17.6 334 7.6 3.04 3.56 3.04 5.4 0.52 0 17.4 417 7.6 4.20 4.45 3.76 5.8 0.25 18.4 362 7.4 1 17.5 420 7.7 4.08 4.48 0.40 2 17.6 424 7.4 4.16 4.56 0.40 18 339 7.3 3.04 3.44 3 17.6 429 7.6 4.20 4.60 0.40 18.3 400 7.3 4 17.6 444 7.6 4.12 4.60 4.24 11.8 0.48 18.4 365 7.3 3.24 3.76 5 19.7 397 7.5 3.60 4.04 6 18.3 318 7.3 3.04 3.20 0.16 19.8 309 7.3 7 18 300 7.4 2.72 3.04 0.32 18.5 305 7.3 8 17.4 434 7.5 4.12 4.52 0.40 9 17.9 477 7.0 4.68 4.96 0.28 18 400 7.1 10 19.6 362 7.2 3.60 3.84 0.24 18.9 215 7.4 2.04 2.08 kitkras1.p65 3.12.98,3:52 93 Black 94 1 Water hardness and SEC at low or medium water level The carbonate content of all observed points was, during a low or medium water table in July in the interval of 2.72 to 4.88 meq/l and the total hardness from 3.04 to 5.44 meq/l. The SEC reached the values from 300 to 500 S/cm and the non-carbon- ate hardness from 0.4 to 0.6 meq/l. Only at Points 6, 7 , 9 and 10 did we find a lower non-carbonate hardness. The Ca/Mg ratio was around 5 at Points b, c, d and 0, and at Dakenyan (4) it was 11.8. All physical meas- urements and chemical analyses of sampled water are presented in Table 1.8.1. The results of the determination of the carbonate content, total hardness and SEC during a low water level (Table 1.8.2., Fig. 1.8.3.) indicate that the water does not flow from Point d in the direction of Point c as was previously assumed. Later, the tracing experiment indicated the flowing from Point d to Point 0. Based on the chemical analyses we can assume that water from Points a, b and c also runs to Point 0. We assume the ratio of the quantity of water from direction d and the quantity from di- rection a, b and c during a low water table amount to approximately 1:1. The water composition at successive Points 1, 2, 3, and 4 indicates the direction of the underground flow through succes- sive points. Water from the spring at Point 9 has a similar composition, but this con- nection has not been confirmed by the trace experiment. We did not take samples at Point 8, but we assume that the water flows in the direction of Point 3. Points 6 and 7 deviate strongly by a notably lower carbon- ate content, total hardness and SEC (Fig. 1.8.3.). We do not exclude the possibility of the connection of water at Point 6 with the spring at Point 10, but for the tracing in July 1996 we used sodium chloride as a tracer, which does not render reliable results when used for longer distances. This is the reason we injected uranin in the second tracing experiment on September 26 th 1997. Water hardness and SEC at high water level During a high and very high water level in July 1996 the carbonate values were up to 1.56 meq/l lower, and the SEC values up to 147 S/cm lower than at a low water level, except at Points 6 and 7, where the SEC dif- ference was minimal. At Point 3 the differ- Janja Kogovek Physical and Chemical Characteristics Fig. 1.8.3. Water characteristics at measurement points during low or medium water levels. Fig. 1.8.4. SEC of water at measurement points during very high and during low water levels. kitkras1.p65 3.12.98,3:52 94 Black 95 1 Janja Kogovek Physical and Chemical Characteristics ence was only 29 S/cm, while the differ- ence at Point 0 was a whole 55 S/cm. By tracing using sodium chloride we found that water drained from Point 6 to Point 2 and then successively to Points 3, 4 and 5. Tracer waves of uranin and sodium chloride (breakthrough curves) appeared at Point 2 simultaneously and travelled in the direc- tion of spring 5 simultaneously thus we did not notice differences between either tracers. The comparison of the SEC at Point 0, 2 and 6 indicates a notable proportion of water at Point 2 from direction 6 during a high and very high water level, which is probably not present during a low water level, that its proportion is insignificant (Figs 1.8.3., 1.8.4.). In the fall of 1997 during high discharge the SEC at Point 6 decreased to 200 S/cm, at Point d to 181 S/cm with a correspond- ing decrease of carbonates to 1.82 and 1.54 meq/l, respectively and total hardness. These were the lowest measured values, al- though insufficient comparable measure- ments were made to allow us to study sea- sonal variations of hardness. The calculated Ca/Mg ratio at the suc- cessive points also indicates that water from Point d flows to Point 0. The elevated value at Point 2 indicates the mixing with water from direction 6 with a larger Ca/Mg ratio, which somewhat increased on its way to Point 3, but did not change significantly to Point 4. Characteristics of the water pulse of underground water flow at Dakenyan During a low water level (Q = 0.35 m 3 / s) the groundwater flow at Dakenyan had a carbonate content of 4.12 meq/l and total hardness of 4.6 meq/l, which means a non- carbonate hardness of below 0.5 meq/l. The water has primarily a high calcium content (4.24 meq/l) and low magnesium content (0.36 meq/l), so the Ca/Mg ratio is 11.8. In July 1996 we installed an electronic temperature and SEC monitor with a data saver (TC instrument, DAS company). We wished to follow the water pulse, that is to define the characteristics of ground water flow at the Dakenyan point (4) following precipitation and during increase and later decrease of its water level. Its water ap- peared later in the Dalongtan karst spring (5). This underground water flow was later accurately traced from its upper flow in the karst hinterland NE of spring (from Point d) by using the fluorescent tracer uranin. We also examined its flow velocity in indi- vidual sections (chapter 1.9.). Regular discharge measurements are made at the hydrological station at Dakenyan four times daily, and after July 19 th the meas- urements took place every two hours for the tracing experiment. Our measurements, car- ried out at one-hour intervals, included tem- perature to an accuracy of 0.1 C, and SEC to an accuracy of 0,1 S/cm. Parallel to this, we took some samples for total hardness and carbonate content analysis. With regard to the data provided by the meteorological station at Dakenyan, where the daily quantity is measured at eight oclock in the morning, 56.6 mm of rain fell on July 16 th , an additional 11 mm on July 17 th , in sum 67.6 mm of rain. On the night between July 21 st and July 22 nd , 26.5 mm of rain fell. From July 1 st , when it reached the value of 0.963 m 3 /s, the groundwater discharge decreased until July 16 th , when it reached its lowest value of 0.354 m 3 /s. Heavy rain- fall on the night between July 16 th and July 17 th triggered a fast reaction of the dis- charge, which reached, during our measure- ments carried out every six hours, the high- est value of 2.24 m 3 /s by the following day at noon. This was probably not the highest value. We assume that water began to flow together from the wider hinterland due to heavy rainfall and caused, in the beginning, the displacement of old water. This points to the delay of the SEC decline by a few hours after discharge had already increased. The discharge increase is followed by the decrease of the SEC and total hardness, and later as discharge decreases, the SEC in- creases again. Precipitation (11 mm) before midday triggered a repeated slight increase of discharge (Q = 1.53 m 3 /s) without a no- ticeable SEC decrease, which slowly in- creased to the starting-point value until July kitkras1.p65 3.12.98,3:52 95 Black 96 1 Janja Kogovek Physical and Chemical Characteristics Fig. 1.8.5. Accurate recording of discharge, temperature and SEC with occasional analyses of total hardness of groundwater flow at Dakenyan (4) in water pulses in July 1996. kitkras1.p65 3.12.98,3:52 96 Black 97 1 Janja Kogovek Physical and Chemical Characteristics 21 st , when it again began to rain in the evening (26.5 mm) and discharge increased to 0.902 m 3 /s, and then gradually declined. We recorded in this last water wave a smaller decrease of the SEC before the in- crease of discharge, which might point to the influence of differences in precipitation in the area of groundwater inflow (Fig. 1.8.5.), indicating complex recharge from various directions changing with precipi- tation and hydrological conditions. When discharge increased six times its previous value in the first water pulse, the total hardness and carbonate content de- creased by 1.6 meq/l, approximately one third of its previous value, a similar amount to the SEC. Similar changes have been found for karst flows in Slovenia. The temperature dropped during the increase of discharge, and then gradually increased. All these changes took place in the range of 0.6 C. Accurate recording of discharge, SEC and temperature (Figs. 1.8.5., 1.8.6.) clearly indicate the conditions in which the trac- ing with uranin and sodium chloride were carried out (chapter 1.9.). Uranin was in- jected at Point d at the final section of a larger water pulse, when discharge slowly declined. Simple tracing breakthrough curves formed in these conditions at Points 0, 1 and 2 (Fig. 1.9.12.). The tracing curve at Point 3 was more flattened, as the water had to pass over the Tianshengan fault, and was formed with regard to a constant, lower discharge. At Point 4 we found the first traces of uranin at the lowest dis- charge and a slight decline in the SEC. The rain, which later caused a smaller water pulse at Point 4, pushed the tracer and ac- celerated the formation of two peaks on the uranin breakthrough curve. More fre- quent sampling, every hour or half hour, would have rendered a complete answer to the question whether there are possi- bly two smaller inflows in the groundwater hinterland. Fig. 1.8.6. Stream flow at Dakenyan: comparison of discharge, SEC and uranin appearance in July 1996. kitkras1.p65 3.12.98,3:52 97 Black 98 1 But we did definitely find that the trac- ing experiment determined the velocity of the flow in conditions of discharge decrease in the range of 1 to 0.5 m 3 /s and also, that the velocity of the flow in section 3-4 would be somewhat less under these conditions than we calculated for the tracing per- formed in July 1996 (chapter 1.9.). The rea- son of higher velocity in sections 3 4 is a later rain event. The comparison of precipitation and dis- charge of the flow demonstrates a rapid re- action of the flow. The flow velocities of wa- ter, as in the tracing experiment, are also rela- tively high during low and medium water levels, from 2.1 to 23 cm/s. This is why we can expect even higher flow velocities dur- ing very high water levels, which in the case of possible pollution means rapid spreading of pollution, that is a very short reaction time. Janja Kogovek Physical and Chemical Characteristics kitkras1.p65 3.12.98,3:52 98 Black 99 1 Janja Kogovek, Liu Hong, Metka PetriŁ, Wu Wenqing Tracing Test in the Tianshengan Area The study polygon near the village Tianshengan in the Lunan province is pre- dominantly agricultural area with frequent problems of water shortage. This typical karst aquifer has plenty of underground water, but the time distribution of the quan- tities of stored water is disadvantageous. A rainy period from May to October is fol- lowed by a long dry period, in which the water reserves are often not large enough for the irrigation of the mainly rice fields. Therefore the agricultural production of the area is very low and problems with wa- ter supply for the villages are also frequent. To resolve this problem, different surface and underground water accumulations are created. To the west and east of Tianshengan two reservoirs are already used, but their ca- pacities are too small. Therefore the possi- bility of constructing a new reservoir has to be studied. For this purpose some basic hydrogeological characteristics of the area must be delineated first. As one of the research methods a tracing test was proposed in order to find out under- ground water flow characteristics in the stud- ied karst aquifer. This was done in July and August 1996. It was the first such experiment in the Tianshengan surroundings, so our goal was predominantly to define the main under- ground flow and to get some basic informa- tion required for planning a more complex tracing and other tests in future. Natural background The climate of the Lunan area can be classified as subtropical with an average an- 1.9. TRACING TEST IN THE TIANSHENGAN AREA Janja Kogovek, Liu Hong, Metka PetriŁ, Wu Wenqing nual precipitation of 796 mm, average rela- tive humidity of 75.3% and average annual temperature of 15.6 C (for the period 1980 - 1992). The amount of total annual rainfall varies considerably and for the observed period between 1980 and 1992 it ranges from 542 mm (1992) to 1066 mm (1991). Each year can be divided into dry and rainy season. The dry season from October to April has only 12 to 20% of total annual pre- cipitation. The polygon for the tracing test covers of 50 km 2 and is located in a broader area of the Shilin stone forest (Fig.1.9.1.). The al- titudes range between 1920 m in the east to 1750 m in the west. The relief undulates very gently. On the slopes of depressions and hills, stone teeth are developed, from 0.5 to 5 m high. Also, pinnacles more than 20 m high can be seen in this area near the Dakenyan. The basic hydrogeological features of the discussed area are summarised from the hydrogeological map, produced in 1993 by the Water and Electricity Survey & Plan In- stitution of Quijing Yunnan (Fig. 1.9.1.) The central part of the studied territory, with an area of approximately 100 km 2 , con- sists of Carboniferous and Permian carbon- ate rocks, among them is a narrow belt of chert sandstone and schist marl, which di- vides the aquifer to the east and west part. Limestone and oolitic limestone, which underwent the karstification process and are highly permeable, are the prevailing carbonate rock. They are characterized by the karst-fissured porosity type. The main drainage routes are underground channels, which compose a heterogeneous karst-fis- kitkras1.p65 3.12.98,3:56 99 Black 100 1 Janja Kogovek, Liu Hong, Metka PetriŁ, Wu Wenqing Tracing Test in the Tianshengan Area sured system together with a network of fissures. Secondary porosity is well devel- oped and the storage capacity is low. Large karst channels with constant or occasional groundwater flow are located near the sur- face and accessible through numerous ver- tical shafts. At low waters the channels are only partially filled with water, and the groundwater level is up to 30 m below the surface during drought. In the wet season the water can completely fill the channels and during the highest water table level even flood the lower lying fields. The wa- ter flow transports large amounts of sedi- ment, which is deposited in the channels when the transport capacity of the stream decreases. The consequence of this process is thick layers of sediment in the caves. The thickness of the belt of quartz sand- stone and shale marl is 20 to 30 m. The rock Fig. 1.9.1. Hydrogeological map 11. Precambrian noncarbonate rocks, 12. Carboniferous and Permian carbonate rocks, 13. Lower Permian clastic rocks, 14. fault, 15. cave or shaft with underground water flow - a sampling point, 16. cave or shaft with underground water flow, 17. karst spring - a sampling point, 18. small spring, 19. surface stream, 20. lake or water reservoar, 21. precipitation station, 22. on the base of tracing test proved direction of underground water flow, 23. on the base of tracing test supposed direction of underground water flow, 24. possible direction of underground water flow, 25. road, 26. village, 27. Shilin stone forest kitkras1.p65 3.12.98,3:56 100 Black 101 1 is poorly permeable, but because it is tectonically fractured and the layer is thin, it does not act as an impermeable barrier. Based on fundamental field research in ver- tical shafts on both sides of the belt, it is possible to conclude that the groundwater flow continues from the eastern into the western part of the karst aquifer. This as- sumption was confirmed by the tracing experiment. The carbonate rocks are bordered by Precambrian sandstone and tuff in the north-east. Cut approximately 300 m deep into it is the Nanpanjiang river, which is hydrologicaly separated from the examined karst aquifer because of impermeable lay- ers in the base. Also classified into the group of impermeable rock are singular patches of Lower Permian basalt and tuff, and Eocene claystones and siltstones on the western and north-western boundaries. They do not, however, affect the hydro- geological conditions in the studied part of the aquifer in the vicinity of Tianshengan village. In the studied area two faults are impor- tant: Tianshengan fault in the N-S direction and the Shibanshou fault in the NE-SW di- rection. Several shafts and caves with un- derground flow, that were observed dur- ing the tracing test, are distributed along the Tianshengan fault. The karst aquifer is recharged in two ways: diffuse infiltration of precipitation through fissures in the carbonate surface, and point infiltration through swallow holes. It discharges concentrated through springs; Dalongtan spring (Figs. 1.9.2., 1.9.3.) near Beidacun village south-west of Tianshengan village, is most important. Similar to Dalongtan, karst water is col- lected by numerous other smaller springs, but their capacities and sizes of recharge area are unknown. During periods of high water table, flow-over points are activated at various heights, and through these the aq- uifer discharges. Due to the small regulation capacity of the system, there is too much water during wet seasons, with floods oc- curring, and a shortage of water during dry Janja Kogovek, Liu Hong, Metka PetriŁ, Wu Wenqing Tracing Test in the Tianshengan Area Fig. 1.9.2. Dalongtan spring (Point 5) at low water level. (Photo A. Mihevc) kitkras1.p65 3.12.98,3:56 101 Black 102 1 seasons. The ratio of minimal and maximal discharge is large. Basing on explorations of karst caves and passages that are accessible from the surface we assumed the directions and ba- sic properties of the underground water flow. Regime of recharge and underground flow was evaluated by daily data of precipi- tations of the area and by discharges at un- derground gauge station from August, 1993 to June, 1996 (Chapter 1.7.). The discharges are measured in the underground karst channel at the Dakenyan pumping station (Fig. 1.9.4.), which is situated 2.5 km north- eastern of the spring. The water levels are observed four times a day and from these values a mean daily discharge is calculated. The precipitation station is also at Dakenyan and the daily precipitations were measured for the same period. The most important spring Dalongtan, is situated in the south- western part of the area at an altitude of 1810 m. As yet there are no exact data about the capacity of this spring. For the planning of the tracing test first some basic hydrological characteristics of the studied area had to be defined. The pos- sible expected discharges were estimated on the base of the characteristics of the measured discharge at the Dakenyan sta- tion. The maximum discharge there was 6.28 m 3 /s and the average discharge 0.47 m 3 /s. In May 1996 the measuring profile in Dakenyan was empty, but it is hard to de- fine the minimum discharge, because in the dry period it is largely controlled by the quantity pumped by different pumping sta- tions. The tracing test was planned for July, 1996, so the characteristic values for this month were compared also. The maximum discharges were 2.92 m 3 /s in July, 1994 and 0.52 m 3 /s in July, 1995. Although we have the data only for a short period, a great vari- ability of hydrologic conditions can be ob- served. On the basis of these values the broader interval of expected discharges in the time of tracing test has been predicted Janja Kogovek, Liu Hong, Metka PetriŁ, Wu Wenqing Tracing Test in the Tianshengan Area Fig. 1.9.3. Dalongtan spring (Point 5) at high water level. (Photo J. Kogovek) kitkras1.p65 3.12.98,3:56 102 Black 103 1 and used in constructing the plan of the experiment. On the base of described data about the studied polygon the tracing test was plan- ned. Tracing test Hydrological conditions at the time of the tracing test After the injection of tracer on July 19 th , 1996, the discharges were measured at the Dakenyan station at shorter time intervals than usual: between July 19 th and 25 th every two hours, and from July 26 th to 30 th , every four hours. The values obtained are pre- sented in Fig. 1.9.13., together with the con- centration curves, and were used for the quantitative analysis of the experiment. At the time of injection the discharge was 0.783 m 3 /s. No water for irrigation was pumped at the pumping stations in this area. The characteristic discharge values for the time of tracer test between July 19 th and August 18 th , were compared with the val- ues of the two previous years (Tab. 1.9.1.). On the basis of this comparison the ob- served period in 1996 can be defined as average; only the extreme maximum dis- charge was lower than in previous years. At the time of the tracer test daily precipitations were measured also. The to- tal amount (P tot ) was 160.9 mm and the maximum daily value (P dmax ) 35.1 mm. Com- parison with the same period of the years Table 1.9.1: Hydrological situation at the time of the tracing test. Time interval Q min Q mean Q max P dmax P tot July 19 - August 18, 1996 0.393 0.817 2.24 35.1 160.9 July 19 - August 18, 1994 0.426 1.064 2.40 75 271.9 July 19 - August 18, 1995 0.214 0.689 4.25 23.3 124.3 Janja Kogovek, Liu Hong, Metka PetriŁ, Wu Wenqing Tracing Test in the Tianshengan Area Fig. 1.9.4. Meteorological and hydrological stations at Dakenyan. (Photo A. Mihevc) kitkras1.p65 3.12.98,3:57 103 Black 104 1 Janja Kogovek, Liu Hong, Metka PetriŁ, Wu Wenqing Tracing Test in the Tianshengan Area Fig. 1.9.5. Injection of Uranin on July 19 1996 at the Point d (Quighuadong). (Photo S. ebela) Fig 1.9.6. Injection of NaCl on July 19 1996 at Point 6 (Wayaodong). (Photo J. Kogovek) kitkras1.p65 3.12.98,3:57 104 Black 105 1 1994 and 1995 shows the same picture as for the discharges. In 1995 the total amount and the maximum daily precipitation were lower, and in 1994 higher than in the ob- served period in 1996. Therefore we can characterize this 1996 year as an average without extreme values. On July 3 1996 10.4 mm of rain fell. The next intensive rain occurred on July 16 in the evening and continued during the night to the next morning; 56.6 mm of rain fell. Rain continued to fall the next morning but less heavy as there were only 11 mm of rain. The next rain followed on July 21 when 5.5 mm fell and on July 22 when 26.5 mm fell. Up to the end of July it rained three more times with a few mm of rain only. In the first three days of August 28.1 mm of rain fell, and from July 8 to 11 an additional 38.8 mm in total; heavier rain occurred on Au- gust 16 and 17 when 35 and 15.7 mm fell. The rainfall in the middle of July in- creased the discharge of underground flow considerably and it reached 1.7 m 3 /s at Point 4; the water transported huge amount of soil and was of an intense orange-brown colour. On July 19 when we decided to in- ject a tracer, the discharge was decreasing and was 0.783 m 3 /s. It continued to de- crease over the next few days and it reached the initial value not earlier than after the rain of July 22. By the end of Au- gust the discharge decreased slowly and af- ter the rain it increased again to 1.23 m 3 /s. The tracing test Inspection of the area where we plan- ned the water tracing indicated possible in- jection points and springs and places where the appearance of the tracer would be prob- able. We measured temperature, SEC and pH and took blind samples and samples for determination of carbonate, calcium and magnesium levels. On a basis of these first measurements and analyses we assumed that the water flows from Point d - Quighuadong towards Point 0 - Yanshidong and not in a direction towards Point c as had been supposed earlier (Fig. 1.9.1.). The analyses suggested that water Janja Kogovek, Liu Hong, Metka PetriŁ, Wu Wenqing Tracing Test in the Tianshengan Area Fig. 1.9.7. We sampled the karst water at 9 sampling points. (Photo J. Kogovek) kitkras1.p65 3.12.98,3:57 105 Black 108 1 flows from the Point 0 towards Points 1 - Maoshuidong, 2 Shihuiyao (Fig. 1.9.8.), 3 - Xiangshuidong and 4 - Dakenyan up to the Dalongtan spring at Point 5 (Figs. 1.9.2., 1.9.3.). We assumed that water at Points 6 - Wayaodong, 7 Guanyindong (Fig. 1.9.9.) and the springs 9 Changshuitang (Fig. 1.9.10.) and 10 Xiniutang (Fig. 1.9.11.) had a differ- ent origin but we did not exclude the prob- ability of connection. Possible injection points could be points a, b, c and d; as the most favourable conditions existed at Point d where discharge was aproximately 30 l/s we chose that one. The second injection point was Point 6 which is a stream in the Wayao- dong cave, having a discharge of 5 l/s. Injection of tracers and water sampling On July 19 1996 from 10.35 to 10.40 a.m. we injected 2 kg of Uranin that was dis- solved in 50 l of water into a stream at the Point d (Fig. 1.9.5.). On the same day from 12.30 to 12.40 we also injected 100 kg of dissolved NaCl at Point 6 (Fig. 1.9.6.). Referring to the previous analyses of rainfall and discharge we made a sampling plan. Point 4 was sampled in most detail. For the first 7 days we sampled every 2 hours, later every 4 hours and then every 6 hours then every 12 hours and after 15 days once per day (Fig. 1.9.7.). At Points 0 and 3 we started sampling every 2 hours and at Point 1 and 2 every 4 hours. To define precisely the maximal con- centrations of Uranin and the time when it appeared we should need slightly more fre- quent sampling at Points 1 and 2. We also sampled at Points 5, 7, 9 and 10. The results of Uranin tracing Uranin appeared at consecutive Points 0, 1, 2, 3, 4, and 5 as shown in Figure 1.9.12.. At other observed Points 7, 9 and 10 Uranin was not detected and we may exclude the possibility of bad connection with these points as we used relatively great quantities of tracer. The flow velocity for single sections of central runoff towards the Dalongtan spring (5) were calculated from air distance and time when maximal concentrations of Uranin appeared at single points (dominant veloci- ties). Real velocities thus might be higher. (Table 1.9.2.) Janja Kogovek, Liu Hong, Metka PetriŁ, Wu Wenqing Tracing Test in the Tianshengan Area Fig. 1.9.12. Breakthrough curves of Uranin at the points 0, 1, 2, 3, 4, and 5. kitkras1.p65 3.12.98,3:57 108 Black 109 1 The fastest water flow appeared in the initial part of its route between the Points d and 0; the slowest was between Points 2 and 4 where it passes over impermeable rocks. After this section its velocity rises up to spring 5 again (Fig. 1.9.1.). The average velocity between injection Point d and the Dalongtan spring (5) is 3.1 cm/s. A tracing experiment in Wulichong subsurface drain- age system in Mengzi County, Yunnan shows the average velocity between 0.6 and 49 cm/s. Water tracings in the Slovene karst Janja Kogovek, Liu Hong, Metka PetriŁ, Wu Wenqing Tracing Test in the Tianshengan Area (HabiŁ et al. 1990, Novak 1991, HabiŁ & Kogovek 1992), when the tracer was in- jected directly into the water flow, indi- cated flow velocities between 0.2 and sev- eral cm/s, and in rare cases only the flow velocity reached values as high as 10 cm/s. We studied more in detail the Uranin appearance at Point 4 (Dakenyan) where every 2 hours we also measured discharge and daily rainfall. Figure 1.9.13. shows the breakthrough curve of Uranin and relative recovery. By the end of July the Uranin con- Table 1.9.2. Air distance, time of tracers travel in respect to maximal tracers concentration and dominant velocity of Uranin and NaCl between observed points URANIN NaCl Distance Distance Time (c max ) Velocity domin Time (c max ) Velocity domin (m) (h) (m/h) (cm/s) (h) (m/h) (cm/s) d - 0 500 0.6 830 23.0 0 - 1 1800 11 164 4.5 1 - 2 1050 8 131 3.6 2 - 3 1250 16 78 2.2 16 78 2.2 3 - 4 1850 24 77 2.1 24 77 2.1 4 - 5 2450 20 123 3.4 22 111 3.1 6 - 2 2000 17 118 3.3 6 - 7 1500 13.5 111 3.1 6 - 9 4050 200 21 0.58 d - 5 8900 80 112 3.1 Fig. 1.9.13. Discharge, breakthrough curve of Uranine and relative recovery of Uranin at Dakenyan Point 4. kitkras1.p65 3.12.98,3:57 109 Black 110 1 Janja Kogovek, Liu Hong, Metka PetriŁ, Wu Wenqing Tracing Test in the Tianshengan Area centration decreased to 0.01 mg/m 3 . Hea- vier rainfall at the beginning of August in- creased the drainage and washed out the remained Uranin. The Uranin concentra- tion rose to 0.070 mg/m 3 , yet it decreased by the middle of August to 0.01 mg/m 3 . By the middle of August, namely one month since the injection, the returned quantity of Uranin was more than 1100 g, more than 55%. Some of remaining tracer was prob- ably washed off later after each rainfall but we did not continue sampling. The results of tracing by NaCl As a second tracer the only one available was NaCl. Injection at Point 6 and observa- tions at the above-mentioned springs showed the water flow to be towards Point 2 and towards spring 5 as already assessed by Uranin (Fig. 1.9.14.). Dominant flow ve- locity up to Point 2 was 3.3 cm/s; other ve- locities to the Points 3, 4 and 5 were practi- cally the same as those given by Uranin. At Points 7 and 9 we sometimes noticed in- creased chloride levels (Fig. 1.9.15.) but only on a few occasions so we cannot state that these ponts are connected. We may conclude that drainage from Point 6 to- wards Point 7 is very probable as the flow velocity obtained from the results would be 3.1 cm/s; drainage towards Point 9 is very questionable as there the flow velocity would be only 0.6 cm/s. More frequent sam- pling or a greater amount of tracer, or a more suitable tracer would probably give clearer picture. It is most probable that water flows from Point 6 in two directions, towards Points 2 and 7; this gives a higher dilution effect and consequently lower con- centrations which must be considered in future. These results indicate a need to re- peat the water tracing from Point 6 with a more suitable tracer. No increase was noticed at Point 10. Even from the physical measurements and chemical analyses obtained we cannot sug- gest possible connections which could be used for future tracing tests. But we noticed the very different reactions to rainfall of the discharges at springs 9 and 10. Fig. 1.9.14. Breakthrough curves of NaCl at the Points 2, 3, 4 and 5. kitkras1.p65 3.12.98,4:02 110 Black 111 1 Conclusions In the studied area the underground karst channels are well developed not deep below the surface. They may be observed at various locations where shafts and caves reach the underground flow and they are proved by high flow velocity which was established by water tracing during me- dium high water level. When discharge is high, drainage may be still faster which is an important fact due to be considered for eventual pollution. The flow velocity slightly diminishes when water reaches the belt of non-carbonate rocks. Stated veloci- ties predominantly vary between 2.1 and 4.5 cm/s, the average velocity for the whole section is 3.1 cm/s, and they correspond to values given for underground waters of southern China by Yuan Daoxian et al. (1991) and Song Linhua et al. (1993): me- dium values of more mm/s and maximal from several cm/s to more ten cm/s. In spite of well-developed underground passages, fast drainage and fact that we in- jected a tracer directly into the under- Janja Kogovek, Liu Hong, Metka PetriŁ, Wu Wenqing Tracing Test in the Tianshengan Area Fig. 1.9.15. NaCl appearance at Points 7 and 9. ground flow, the returned quantity of tracer is relatively low. Uranine adsorption into soil studied by laboratory experiments did not show any possibility of an important tracer adsorption. This is why we admit a possibility that a part of underground flow was not included in the sampling after trac- ing test. It seems probable that a part of water flows along the Shibanshou fault through a belt of non-carbonate rocks and feeds smaller springs or superficial flow on its western side. The maximal decrease of tracer concentration was noticed between the Points 0 and 1. Similar conclusion indi- cate the stated main directions of under- ground flow N-S and E-W and comparison with underground flow between Points 3 and 4 (Fig. 1.9.1.). Comparing the discharges at Points 4 and 5, which were due to changeable hy- drologic conditions only estimated, we no- ticed considerable increase in discharge of the Dalongtan spring. We assume that the observed underground flow from NE direc- tion is not the only feeding source of this spring. kitkras1.p65 3.12.98,4:02 111 Black 112 1 Janja Kogovek, Liu Hong, Metka PetriŁ, Wu Wenqing Tracing Test in the Tianshengan Area As already mentioned, the described water tracing test gave us only some basic information regarding the properties of the underground water in the treated area but it also raised a series of interesting ques- tions. Let us quote only some of them: does the water drain along the Shibanshou fault and if this is the case, what is its rate? What role does the flow passing Points 6 and 7 play and where is its continuation? Is there any connection between springs at Points 9 and 10 in spite of our negative results? The answers may be obtained by new in- vestigations which are already planned by Chinese experts for the future. kitkras1.p65 3.12.98,4:02 112 Black 113 1 Martin Knez, Janja Kogovek, Tadej Slabe Jiuxiang Jiuxiang is an underground cave open for tourists, 90 km from Kunming, the capi- tal of Yunnan and 20 km north of Stone For- est. Cave visitors gather in a pleasantly ar- ranged reception hall. The tourist path runs parallel to the surface and subterranean can- yon and then continues into the vast cham- bers. The Mai Tian river flows into the cave and flows in the canyon bed (Figs. 1.10.1., 1.10.2.). Deeper into the cave there is an interesting double waterfall, the tourist path passes through numerous passages and large chambers with flowstone forma- tions, of which the large gours across a vast slope in a chamber stand out. The visit to Jiuxiang cave gave us an impres- sion of similarity to kocjanske jame cave in Slovenia. 1.10. JIUXIANG Martin Knez, Janja Kogovek, Tadej Slabe Fig. 1.10.1. The Mai Tian river at the entrance in the Jiuxiang cave. (Photo S. ebela) Fig. 1.10.2. The Mai Tian river. (Photo J. Kogovek) kitkras1.p65 3.12.98,4:02 113 Black 114 1 Martin Knez, Janja Kogovek, Tadej Slabe Jiuxiang Lithostratigraphic characteristics of the rock in the cave Nine locations for taking samples were chosen in the cave (Fig. 1.10.3.) in the ar- eas where we observed a change in lithol- ogy or outstanding bedding-plane (Figs. 1.10.4., 1.10.5.). Eight samples were taken from the cave walls and one from the un- derground river bed (a siliceous sandstone pebble). The samples were microscopically examined. A complexometric analysis was done on all the samples. Microscopic inspection of the thin sec- tions revealed characteristic stromatolite and/or biopelmicrite to biopelsparite dolo- mite of the boundstone type (biolitite), standard microfacies 20 (SMF 20). Among the biogenic components the skeletons of blue-green algae prevail. Pelitic rock and rock derived from pelitic metamorphism processes are represented in the rock by only a few percent, exceptionally up to 10 percent. Besides singular non-transparent minerals, there are no allochemes in the sample. The rock in the second part of the cav- ern gradually and continuously changes from stromatolitic biolite into characteris- tic laminite, standard microfacies 19 (SMF 19). The rock in this section does not con- tain biogenic components. Here and there we found fenestrae filled with chert. In general we found that among the oth- erwise simple lamination, areas with fre- quent pelitics and areas with characteristic fenestrae are found. Despite the fact that in the thin sections the lamination is clearly expressed, in the exposed rock on the sur- face, here and there it is macroscopically completely blurred. Of the types of secondary porosity, fenestral, intercrystal and vugy porosity are most common. Calcimetric analyses showed that the total carbonate values vary from nearly 100% (99.29%) at point 2 to more than 80% (81.23%) at point 9. The difference to 100% is always the insoluble remainder. At the Ca/ Mg value between 1.42 and 35.75 we found that the proportion of CaO in the sample ranged from 24.96% to 52.72% and the pro- Fig. 1.10.3. The cave interior illuminated by many-coloured bulbs. (Photo M. Knez) kitkras1.p65 3.12.98,4:02 114 Black 115 1 Martin Knez, Janja Kogovek, Tadej Slabe Jiuxiang Fig. 1.10.5. Detail of figure 2. (Photo M. Knez) Fig. 1.10.4. One of the most important bedding-planes in the entrance part of the cave. (Photo M. Knez) kitkras1.p65 3.12.98,4:03 115 Black 116 1 portion of MgO in the sample ranged from 1.61 to 21.36%. From the calculation it fol- lows that the proportion of calcite in the samples is between 0% and 90.08% and the proportion of dolomite in the samples be- tween 9.25% and 99.59%. Seven out of eight carbonate samples are almost completely pure dolomite. The colour of the rock in most of the cavern is between N4 and N6 by the Rock colour chart. Rock relief in the cave The cave rock relief is composed of vari- ous rock formations: ones that indicate ini- tial water flowing at lesions formed by slow stream flow which used to run through the cave, ones that are signs of a faster flow present today, and the sign of slow flows of water above the fine particle alluvial sedi- ment. The remnants of the anastomoses be- tween the rock strata, some cm to dm wide grikes, show how the cave began to form. The anastomosis network is most usually visible as cut off grikes in a rock frame. The orifice is frequently widened into pans formed by a slower water flow which flooded the cave and whirled around the dissections. Traces of the early phase of the cave de- velopment, when a slow stream flowed through the flooded cave, are ceiling and wall pans on the frames of passageways which were not deformed by disintegra- tion. Small, higher located and currently dry passage ways are dissected into spongy forms (Fig. 1.10.6.). On their frames we find ceiling and wall pans, and from this pro- trude rounded horns, dissected by rock bridges. All these forms are traces of slow water flow through porous or cleaved rock. Traces of slow water flow are also on the passageway ceilings, which deepened the water flow with a free water table. This is what most effectively forms the cave today. Fast water flows chisel small facets and potholes (Fig. 1.10.7.). In a part of the cave, flutes on alluvial sediment (Slabe 1995) are preserved, indicating that the cave or at Martin Knez, Janja Kogovek, Tadej Slabe Jiuxiang Fig. 1.10.6. The passage shaped by slow water flow. (Photo T. Slabe) kitkras1.p65 3.12.98,4:03 116 Black 117 1 Martin Knez, Janja Kogovek, Tadej Slabe Jiuxiang Fig. 1.10.7. Scallops due to fast water flow. (foto T. Slabe) Fig. 1.10.8. Jiuxiang cave: sampling points of percolation water A, B, C, D, E and F. kitkras1.p65 3.12.98,4:03 117 Black 118 1 Martin Knez, Janja Kogovek, Tadej Slabe Jiuxiang least a part of it was filled with fine particle sediment, across which small water flows ran and cut characteristic forms into it. The rock relief reflects the most evident stages of the development of the cave. The cave developed from a network of grikes in rock strata. Slower flows, which completely flooded the cave enlarged and formed some of the initial grikes that then grew into pas- sages. This period was relatively long in duration, which is reflected in the size of the middle passageways with traces of slow water flow. The water flow began to deepen the cave because of the lowering of the un- derground water table. It was occasionally flooded and during heavier flood periods it was filled with fine particle sediments. When the cave was filled for a long period of time, the water flowing above the sediments left marks on the passageway ceiling. The process of fast water flow cut- ting into the bottom of the rock continued from then on and remains the main factor in forming the cave. Water in the cave The Jiuxiang cave has a submerged river and percolation water supplied by precipi- tation. There had been no heavy precipita- tion two weeks previous to our visit in July 1996. We noticed a number of drips and tiny trickless and took three samples of per- colation water (Fig. 1.10.8.). We also took a sample of Mai Tian river (Fig 1.10.9.). Dur- ing our next visit in September 1997 we again took a sample of Mai Tian river, four samples of percolation water and inflow water to the large and small gours. Mai Tian river On July 13 th 1996 Mai Tian river water taken from in front of the swallow hole at 13.00 was medium-turbid, the discharge was somewhat higher, the temperature measured was 20.1C, specific electric con- ductivity (SEC) 184 S/cm and pH 8.26. Be- Fig. 1.10.9. Sampling of the Mai Tian river . (Photo M. Knez) kitkras1.p65 3.12.98,4:03 118 Black 119 1 Martin Knez, Janja Kogovek, Tadej Slabe Jiuxiang fore doing further analyses we filtered the sample through the blue ribbon filter, but it remained turbid even after filtration, which indicates the presence of very fine solid particles. The water contained 1,76 meq/l (107 mg HCO 3 - /l) of carbonates and 0.88 meq/l (17.6 mg Ca 2+ /l) of calcium. The magnesium content was the same as the calcium content, so the Ca/Mg ratio (Ca and Mg in meq/l) was 1, which indicates that the river water is supplied from a dolomite area. We took a sample from Mai Tian river in the same spot next year on September 23 rd during a slightly higher, although de- creasing water level. Lower temperatures in this season caused a lower river water temperature, which was 17.7C, the SEC was 147 S/cm and the pH 8.95. The water contained 1.42 meq/l of carbonates, 0.84 meq/l of calcium and 0.64 meq/l of magne- sium, the Ca/Mg ratio thus being 1.3. In comparison with percolation water in the cave, the SEC and hardness values of the river water were noticeably lower. Percolation water The Ca/Mg ratio of water in the samples from Jiuxiang cave was also around 1, indi- cating that precipitation water percolates through dolomite rock and/or dolomitised rock. Sample A-97 (Table 1.10.1., Fig. 1.10.8.) was taken on September 1997 from a drip from the cave ceiling with a discharge of around 10 ml/min, located on top of the stairs in a passageway leading from a can- yon to an otherwise very dry part of the cave. We took sample B-96 in July 1996 from a heavier drip, which was almost a trickle, with a discharge of approximately 70 ml/ min falling from the 5 m high ceiling into a collector in the vast room (Fig. 1.10.10.). The immediate measurement of the SEC in- dicated high values, and due to this we as- sumed a possible pollution source on the surface. A subsequent comparison of car- bonate content and total water hardness of this sample with the other ones indicated the same. After visiting the cave we took a chair lift to the starting point. We found that Fig. 1.10.10. Sampling of percolation water at point B. (Photo J. Kogovek) kitkras1.p65 3.12.98,4:03 119 Black 120 1 Martin Knez, Janja Kogovek, Tadej Slabe Jiuxiang the end station of the chair lift is located approximately above the room where we had taken the sample (Fig. 1.10.11.). This is how pollution from the surface is possible. Unfortunately, we were unable to carry out the analyses of the content of nitrates, chlo- rides and sulphates, which could confirm our assumptions. In September 1997 we took another sample of the B-97 water and found the val- ues of SEC and total hardness to be lower, 9 mg/l of chlorides and a higher content of sulphates, which were determined only qualitatively. Measurements and analyses are presented in Table 1.10.1. and Figure 1.10.12. The heavier drip at point C in the side passageway had a high SEC and chiefly an increased hardness. It also contained 6 mg/l of chlorides, but the sulphates were not higher. Unfortunately, we were once again not able to determine the nitrate con- tent. Flowstone deposition in gours Jiuxiang cave is adorned with variously large flowstone gours in four different lo- cations. The largest gours are on a vast slope and are several times larger than the ones found in kocjanske jame cave. These gours, Table 1.10.1. Measured parameters in percolation water in the Jiuxiang cave. Place Discharge T SEC pH Carbonat. Ca Mg Total h. Ca/Mg ml/min C S/cm meq/l meq/l meq/l meq/l A - 97 331 8.40 3.36 1.28 2.07 3.35 0.6 B - 96 70 20.0 605 8.40 5.12 2.72 2.88 5.60 0.9 B - 97 17.2 500 8.15 4.75 2.47 2.44 4.91 1.0 C - 97 100 15.9 615 8.03 5.28 3.19 4.15 7.34 0.8 D - 97 692 7.68 7.70 3.47 4.27 7.74 0.8 E - 96 17.5 514 7.80 5.04 2.80 2.80 5.60 1.0 E - 97 15.9 556 7.70 5.75 3.35 2.99 6.34 1.1 F - 97 15.2 394 8.40 4.21 1.88 1.62 4.39 1.2 Fig. 1.10.11. View to Jiuxiang cave from chair lift at the end of our visit . (Photo J. Kogovek) Fig. 1.10.12 . Carbonate, calcium, magnesium level and total hardness in percolation water. kitkras1.p65 3.12.98,4:03 120 Black 121 1 Martin Knez, Janja Kogovek, Tadej Slabe Jiuxiang like those in kocjanske jame cave, do not have a regular flow of water. Smaller gours, which are continuously filled with water, are at their base. During our September 1997 visit we managed to take a sample of water that flows into the larger gours, this is sample D-97. This water contains noticeably more dissolved carbonates in comparison with the flow into the smaller gours (Eo) and thus we can expect more intense deposi- tion (Table 1.10.1.). But the gours were only half filled with water. The previous year in July, when the rainy season had hardly be- gan, there had been no flow. This is why it would be advantageous to direct the water to fill all the gours after precipitation, that is when the inflow is active. For the further maintenance of the gour, a small amount of oversaturated water would suffice, de- pending on the extent of evaporation. Measurements and analyses of the in- flow water (D-97) indicated the highest measured SEC and hardness values of our analyses of percolation water in the Slove- nian and Yunnan karst. Due to the fact that hardness varies throughout the year with the highest values at the beginning of the rainy season, similar to the spring flows in this karst, we assume that we would have measured even higher values during that period. Analyses indicated higher values of magnesium in comparison with calcium (in meq/l), which we have never found in the Slovenian karst. The diversity of percolation water composition through the length of the cave indicates a varied geological struc- ture, which will probably be confirmed by detailed rock analyses, for which numerous samples have been taken. During our first visit in July 1996 we took samples of water in smaller, lower ly- ing gours, that is the inflow water to the first gour (Eo-96) and carried out measurements in lower subsequent gours (Fig.1.10.13). The SEC measurements indicated a subse- quent decrease of values, which is why we assume flowstone deposition, that is recent growth of the gours. Since we did not man- age to take a sample of the water before the first gour, we assume that it has an even higher SEC and/or higher carbonate con- tent. In Autumn 1997 we measured higher values in the first gour, which probably in- dicate an even heavier deposition in the recent conditions. To revive the larger gours oversatura- ted water would be required, that is water with a high carbonate content. Mai Tian river water, which usually transports a large amount of solid particles is not adequate, because it has different chemical composi- tion with only a fifth of the carbonate and total hardness and could cause dissolution of the gours. Fig. 1.10.13. Flowstone deposition in small gours in Jiuxiang cave. kitkras1.p65 3.12.98,4:05 121 Black 122 1 Previous studies Research into the corrosion of carbon- ate rocks mainly uses three methods: 1. To calculate the weight of dissolved carbonate per unit drainage area either by measuring river run-off with its concentra- tion of dissolved rock and the boundaries of the river basin, or to calculate from the rate lowering of the rock surface, using the formula: X=4ET/100 where X is the solution rate (m 3 /km 2 / year or mm/1000 year), E is run-off (dm) and T is the average concentration (mg/l). 2. By using tablets of carbonate rock of standard weight, noting their structural characteristics and exposing them in the field. They are then reweighed after a known period and the loss in weight is the amount dissolved in that time. From that the volume dissolved can be obtained and can be converted into rate of surface lowering. It was suggested by Gams (1981) from analyzing 1500 tablets in eight countries and Day (1986), from test results in Wiscon- sin (USA) and in the Brasil, that: (a) The amount of solution is generally greater on tablets placed in the soil then on the surface or above it. The solution rate depends more on the difference between precipita- tion and evaporation than the temperature. (b) The solution rate is highest in humid tropical area. (c) The influence of different rocks is greater than the effect of climate. (d) Even in areas where solutional denu- dation is very active, the effect of mechani- cal erosion may also be very clear. 1.11. A STUDY ON RECENT KARST DENUDATION RATE OF KARST IN SHILIN, STONE FOREST Liu Hong Yuan (1988) measured the solution rates on 12 tablets under different climatic conditions on the ground surface and also 20 and 50 cm deep in the soil. He concluded that: (a) In damp climates the tablets in the soil are denuded more than the surface above it. This result is associated with bi- otic action and the high concentration of CO 2 in the soil. (b) The case with which water can pen- etrate the soil has an important effect on solution rate. Yuans results give average solution rates for tablets buried in the soil at depths of 20 and 50 cm 33.96 mg/100d and 32.05 mg/100d respectively. For tablets on the ground the average solution rate was 14.46 mg/100d, and for tablets 1.5 m above the ground it was 16.42 mg/100d. The solu- tional denudation rate obtained from tab- let tests is usually less than that calculated from water hardness and run-off data (Williams & Ford 1989). 3. Direct measurement of the denuda- tion rate by micrometrical method. This is usually suitable only for measure- ment over long periods. It has been used by the Karst Research Institute in Postojna to measure the surface denudation rate in Snena jama cave NW Slovenia. The authors of China Lunan Stone For- est Karst Research (1997) have calculated a denudation rate by combining the result of water hardness, change of rock volumen and weight, rate of fissure development and rate of formation of karst fractures. They conclude that it is between 32 and 73 mm/ 1000y in the Shilin stone forest, using Cor- Liu Hong A Study on Recent Karst Denudation Rate of Karst kitkras1.p65 3.12.98,4:05 122 Black 123 1 Liu Hong A Study on Recent Karst Denudation Rate of Karst bel formula, they calculated the denudation rate in Luoping county, 99 km west of Lunan stone forest as 51.53 mm/1000 years. This figures may be compared with those obtained by Yuan (1989) above. Methodology Rock samples were obtained from the Permian Maokou limestones. They were prepared as 88 tablets 5 cm diameter and 0.5 cm thick, which in July of 1996 were placed in various parts of Shilin stone for- est. To allow for the possible effect of soil depth (5 to 50 cm), hydrological conditions and locations, the tablets were located in depressions located on hillsides of various gradients, at their edges, on their slopes and in the soil of the bottoms. Some of tablets were placed in water, as at Sword Pool. 45% of the tablets were recovered about a year later, in September 1997. After washing, the tablets were dried and weighed (with an accuracy to 0.0001 g). The weights lost in- dicate the solution rates under present cli- matic and hydrological conditions in Shilin stone forest. Results The maximal denuding rate occurs at the tablets buried in the soil and the lowest at tablets interspersing at rock dissolutional fissures where the rain is not easy drench- ing. The denuding rate of tablets placed at the stone crests or in woods, is in the mid- dle. Maximal loss weight occurs under Ashima stone pillar (20 cm in the soil) with 1.8946 g/y. The minimal value (0.0068g/y) presents at »hog bajie ate watermelon« stone crests rock fissure, buried 5 cm un- der the thin soil. This except chemical denu- dation, weight loses primarily owing me- chanical broken. As a result of corrosions along porousness and fissures of rock on- going first of all, it may cause the rock drop- out possibly. It has been found that with the proportion of dolomite increasing in lime- stone the mechanical disintegrative quan- tity of limestone increases too (Gao Zhang et al. 1986). Additionally, there is a relation- ship between rocks micro-fissures develop- ing degree and mechanical disintegrative amount, the mechanical disintegrative quantity can occupies 27% of whole denud- ing quantity (Weng Jintao 1987). Comparing with the work of Michael Day (1986) in Belize Karst depression, both results correspond. The surroundings of these tablets that were placed at stone col- umn in study area are similar with that steep cliff of Michael Days, and the weight loses are conformable too (Table 1.11.1., 1.11.2.). If we omit their placing surroundings, the 45 pieces tablets mean that the weight loss is 0.1221 g/y. After deducting 7 pieces Segment type near base midslope near summit Staircase 0.0521 0.0213 0.0216 Broken Cliff 0.0215 0.0110 0.0260 Inclinal bedrock 0.0527 0.0217 0.0305 Talus 0.0303 0.0201 Table 1.11.2. The average weight loss (g/y) statistics in Shilin stone forest. * Deducts these tablets that weight losses caused by mechanical disintegration clearly, the average weight loss is 0.0196 g/y and 0.0622 g/y respectively and 0.0369 g/y is the average value for the stone columns top. Table 1.11.1. Tablet weight mean losses (g/y) by slope segment type and location (From Micheal Day, 1986). Central section fissures of pillar Vegetation cover Roofing with no vegetation 0.0153 0.0103 Buried under soil 5 mm 10 mm 15 mm* 20 mm 30 mm 40 -50 mm* average 0.0197 0.0315 0.1209 0.0293 0.0469 0.2947 0.1807 Peak of pillar average weight loss* Maximum Minimum 0.0654 0.3878 0.0156 Earths surface rainwater not easy drenching rainwater easy drenching average 0.0013 0.0454 0.0160 kitkras1.p65 3.12.98,4:05 123 Black 124 1 maximize value samples, the average weight loss is 0.0454 g/y. These samples placed in stone column central sections where the rain can not easily reach the dissolve loss quantities are quite smaller than others. During the testing period, there are also some rainfall samples collected for ana- lyzing the quality of precipitation in the Shilin stone forest area (chapter 1.6.). In the study area the cave roof percolation waters were also taken and analyzed (chapter 1.6.). Discussion Precipitation is the main controlling fac- tor on the rock (chemical) denudation. For a good understanding the effect of precipi- tation on the stone forest development, some tablets were laid at rock stone pillar fissures. A part is opened to precipitation drip washing, and others not for the con- trast specially. The average corrosion quan- tity for those tablets lying at the surface where not easy pouring rainwater is 0.0013 g/y, but for those where the rains may di- rectly pour is 0.0454 g/y. Both are nearly 35 times different. For those tablets placed at the central section of the stone column where there is not easily directly to get rain the mean de- nuding weight of the rock sample is 0.0058 g/y. The average loss weight for those put at the stone pillar upper part is 0.0438 g/y. Rainwater from the stone column top underwashing drowns and forms a quick- speed flow that is not yet come up to a satu- rated state. This is very helpful for the rock surface ionic carry and CO 2 supply, and can enhance the chemical denudation speed of carbonate rocks (Yu Jinbiao et al., 1990). It is one of the main reasons for the develop- ment dashing groovy on stone columns. The quantity and runoff speed are limited owing to the tested samples placed partially near the upstream of the canal, it is hardly able to reflect any very big variant. Both of weight losses have a difference of barely 7.5 times. Flatting dissolve grooves or denud- ing, and it seams they are widely developed at the central section of the stone pillar along the rock stratum bedding planes in the Shilin stone forest, it is formed under the soil buried or under water conditions. Even if the rock is covered up by the soil, if the rain water unables direct-acting at the burial places, the denuding amount of its is also very low, in Nantainman only 0.0015 g/y. Compared with the average denuding amount of the under soil, it is 120 times lower. For rainfall features of the stone forest area, there are torrential rains, as well as mizzly rainfalls (chapter 1.6.). The torren- tial rain has a big rainfall amount but the endurance time is short. It plays a very im- portant role in forming of stone column surface ditches. Its contacting time with rocks is brief, in contrast to small rainfall amounts mizzly, the denuding-quantity of the former should be smaller than that of the latter. Therefore, the length of the rain- water-rock action time and the amount of precipitation have a determinant action on the carbonate rock corrosion process. This is in tune with the Yuans research (1988). The karst features caused by the crea- ture action at carbonate rocks is called the biotic karst. The majority of the rocky sur- face is not completely bare, but is covered by a thin layer lichen, algae alga or other stone surface, fissure and inter-rock organ- ism. By now, their machine-processing on the carbonate rock denuding is not yet wholly understood. It may be connected with the excretory organic acid, raising of the relative humidity and CO 2 emission. Danins (1983) study in Israel shows that orchid algae can yield a dissolving rate of 5 mm/ky. Once for a time it is agreed that vine and wood growing on the stone column have very big effect on the chemical denu- dation procedure of the stone column. Ear- lier some tablets were specially placed un- der vines or trees of the stone pillars, for taking measure of the lianas effect onto the stone column. After the precipitation passes through the crown and tree trunks, the acidity of rainwater can be grown up (Yu Jinbiao 1990), and it consequently has enhanced its chemical denudation ability. 7%-43% of the total rainfall is hindered by transpiration. Stones pillar surface micro-figures are a lit- Liu Hong A Study on Recent Karst Denudation Rate of Karst kitkras1.p65 3.12.98,4:05 124 Black 125 1 tle bit different between the pillars with the vegetation and those without vegetation. The stone pillars with plants appearances are not very fluent. The surface up and down is greater than the one with no veg- etation. This is because dripping water of a crown is unlike the meteoric water that can uniformly act on the rock surface. Com- monly, there are small corrosion pits devel- oped on the rock surface of 1 cm depth and the diameter from 1 cm to several cm. At the Major and Minor stone forest, because of the stone column superficies plants cleavage, all might eye out it in the reserve prints. The surface of the stone column ap- pears with white color, but other pillars with no vegetation covered present black- ash color. It may related to the vegetation keeping off the rainwater and sunshine, as well as related possibly to microbio selec- tive living. The rock under woods is awkward to have rainwater uniformly brushed during the light rain. Only during the downpour hours the precipitation is able to yield a strong action on under rocks. Therefore, the chemical denudation amount of those tablets which are placed under the plants is not as high as the supposed amount, the average value is 0.0153 g/y (Table 1.11.2.). The root system of the vegetative growth pitches into rock gap deeply, and this procedure contributes to the rainwa- ter ingoing, yielding corrosion and me- chanical spallation. Therewith, plant root systems dissolve out organic acid and yield strong chemical denudation action on car- bonate rocks. Occasionally, there are flut- ing figure forms at the plant root system or liana adhesive places. This kind of figures can normally be seen in the Shilin after the woods or vines of the stone column were cleaned out. Except for its acidity increase and denuding ability reinforces after the meteoric water the transition through tree trunk and crown, it may be also concerned with the moisture of that place, and the holding-up time is longer than other places owing to the root or vine coherence. At the places where vine and rock touch there grow out fibrous roots acting on the rocks. There are samples laid under vines and at the joint positions of the vine and rock, unfortunately, there are only two pieces preserved. They all have fibrous roots (lateral roots) growth. Due to the lim- ited time, these two samples corrosion quantities were not very high, 0.0209 g/y and 0.0156 g/y respectively. The tablets buried at the depression side slopes (gradient 20-25, burial depth 30 cm) have an average loss weight approa- ched to 0.0804 g/y. The tablets mean denud- ing amount is 0.1326 g/y. The samples at the top gentle district of the depression with the same burial depth, the mean loss weight is only 0.021 g/y. From top to bot- tom, the loss weight of the tablets has in- creased progressively 3.8 times and 6.3 times respectively. Besides hydrological and topographical factors, it is a concern with soil behaviors. On the top there are cypresses and pine trees growing, and under them there devel- ops loosely humid earth having a worth- while penetrating property of water. Under the effect of the dry-wet season clear cli- mate, the surface layer soil moisture during the dry season is terrible low, that is to say that the procedure of chemical denudation speed is very low, too. For the depression central slope area, the grasses grow well on the surface, but the depth of the soil is rela- tively thinner. The depth of the samples buried is almost to the rocky zone. The earth could hold certain humidity during the dry season. At the bottom of the depression the soil viscosity is high and easily hardened. In most cases the water holding property and penetrating ability are not all equal to the former, but in the wet season there can form impermanent storing water, soil mois- ture all along very high. Meanwhile, the water penetrating capability along the bor- der of rocks and soil (sediment) is very high that approximated to the conduit level. In the Busaoshan area the weight loss of tab- lets with 10 cm, 20 cm, 30 cm and 40 cm burial depth in the bottom of the hollow are all over 0.2 g/y. According to the weight loss statistics, the average corrosion speed of the earth surface and the top of stone pillars is 10.4 mm/ky in the Shilin stone forest area and Liu Hong A Study on Recent Karst Denudation Rate of Karst kitkras1.p65 3.12.98,4:05 125 Black 126 1 1 the under earth mean speed is 28.77 mm/ ky. There are 2.7 times different between them. That is to say that the Shilin stone for- est under soil still keeps growing by the speed of 18.37 mm/ky. Reckoning on this speed, if the stone forest could develop to the nowadays dimension, over 30 m of stone pillars, it will need about 1630 thou- sand years, equivalent to the Middle Pleisto- cene period. This coincides with the results by Liu Xing(1998) and the authors of China Lunan Stone Forest Karst Reseach(1997). By means of ESR dating, they think the stone forest predominately developing period is Middle Pleistocene. The ESR date of Dadie- shui waterfall ancient river course adarce sediment is 1350 thousand years old, that is to say that the Shilin stone forest and Dadieshui cascades are the offspring of the same period karst. Liu Hong A Study on Recent Karst Denudation Rate of Karst Conclusion Deducting the influence of the rocks, the rainfall is the main motivation of the karst developing. In most cases the amount of carbonate rocks denuding of the under- earth is 2-3 times bigger than that of the earth surface. The undersoil denuding is regarded with the edaphic water-holding behavior and landforms sites. The vegeta- tion activity is not as big as preconceptional in-process of the stone forest development. According to the today karst developing speed, the Shilin stone forest mainly devel- oped period is Middle Pleistocene. It is the offspring of the corresponding periodical karst with the Dadieshui waterfall. kitkras1.p65 3.12.98,4:05 126 Black 127 1 Chen Xiaoping The Analysis Research on Soil Erosion Characters ... The karst environment is a special physi- cal environment. Specially, there is mainly a distribution of tropic and subtropic karst mountain areas in the Yunnan-Guizhou Pla- teau and Guangxi area, China. It has a com- plex geomorphological character, steep slope and rugged mountain, thin soil layer, widely spread stoneteeth, discontinue soil layer, lesser vegetation cover, deep under- ground water and dry ground. Thus, it shows a fragility of the low environment capacity, high variant sensitivity of the eco- system, small elasticity of the catastrophe duration threshold value. Due to the high density of population, limited farmland and influenced by the unreasonable human be- ing activity of the denuded forest, it results in the soil erosion increasingly in the karst mountain area. And it leads to the originally thin soil layer erosion, poor farmland, bare rock and waste mountain which have ex- tended with an obvious desert trend and resulted in a disastrous effect to a worse ecosystem, lack of water, drought or exces- sive rain disaster aggravation, deposited and destroyed farmland, danger to the water conservancy and traffic facilities, and dan- ger to the local social economic production and life. It is seldom researched, specially about the soil erosion in the karst mountain area environment, and it is still weak at present. Even the problem related to the soil erosion in the karst mountain area, it is still judged through the non-karst erosion level. It is often concluded that the karst area has a character of a slight erosion. It gives a bad influence on water and soil conservation in the karst mountain area. Therefore, it is im- portant to think high of carrying out the 1.12. THE ANALYSIS RESEARCH ON SOIL EROSION CHARACTERS IN KARST MOUNTAINS AREA ENVIRONMENT XICHOU OF YUNNAN Chen Xiaoping research work. This paper is based on the observation research work by the author in the typical research area in the peak-clus- ter depression area in the Southeast of Yunnan. The soil erosion problems on char- acters, reason, erosion level index and pre- vention and control in the karst mountain area is analysed and discussed. The soil erosion character in the karst mountain area The soil erosion actuality and latent dan- gerousness The soil erosion widely arisen. The ero- sion area is up to 2/3 of the total area in the karst mountains. Due to the fragility of the karst mountain environment, it comes to a result that once the key element forest-soil system is destroyed, the soil erosion will certainly aggravate. At present, many forest vegetation is destroyed in the wide karst mountain ex- cept in some karst forest nature reserves, and provide a wide condition for the soil erosion. According to the research works by Cai Zongxin(1989), it shows that the karst soil erosion area in the Guangxi area is up to 69,742 km 2 , it occupies 90% of the total karst mountain area. The annual mean eroded modulus is 265.5 t/km 2 . The total eroded amount in one year is more than 18,000,000 t. According to the statistics the soil erosion area is more than 70% in the peak cluster mountain area in the southeast of Yunnan. The annual mean modulus in one year is up to 380 t/km 2 . The soil ero- kitkras1.p65 3.12.98,4:05 127 Black 128 1 sion area is up to 253km 2 in the erosion re- searched region of the peak cluster moun- tain, Xichou county (Song Linhua, et al. 1991, Synthetical research on the water, soil and biological resource in the karst peak cluster area). It occupies 76% of the total area in the region. The annual mean eroded modulus is 387.7 t/km 2 , and the annual eroded amount is up to 98,100 t or similar. (Tab. 1.12.1.) The soil erosion grade of intensity in the karst mountain area is mainly middling and strong erosion. Regardless the proportion- distributed area or amount, the middling and strong erosions are both proper. This reflects the soil erosions in a serious situa- tion in the karst mountain area. Among the soil erosion distribution area in the Guangxi province, the erosion area serious is like the middling one up to 11,794 km 2 . The ho- mologous erosion amount is 17,100,000 t. These occupy a part of 80% of the total ero- sion area, and 95% of the total erosion amount. In the erosion research area in the peak cluster mountain of Xichou in the southwestern Yunnan the middling and the strong erosion area is 208km 2 , and they oc- cupy 82.2% of the total erosion area. Its ero- sion amount is 95,850 t, and occupies 91.7% of the total erosion amount. The latent dangerous degree of the soil erosion is extremely serious. Influenced by the steep slope, and the special soil form- ing factors in the karst mountain area, the slope soil layer is often shallow and slight. The average soil layer thickness is 30150 cm on the peak-cluster slope in the west- ern Xichou (Tab. 1.12.2.), and less thick, only 30-60 cm, in the Nonggang peak-clus- ter slope of Guangxi. By the steep slope con- dition, and by no protection of the forest the soil layer erosion would arise more se- riously, and the erosion intensity would in- crease rapidly. According to the observation of the erosion serious site of the Longtan peak-cluster slope of the western Xichou on 6 June 1998 the erosion amounted to 72 t/ hectare, and was formed after a storm with the duration of one hour and precipitation of 35 mm/hour. It is equal to the intensity grade of a short dated extreme erosion of 7200 t/km 2 and the soil layer was eroded to the depth of 5.7 mm. Generally, the bare soil belt with a relative thickness of the steep peak-cluster has an extremely strong soil ero- sion. The annual eroded depth range to the soil layer is from 5 cm to 10 cm, and at rare places there can be 30 mm. The surface soil layer is eroded to become thin to empty, and the environment develops to the direction of rock-land mountain or rock-desert. There is the formula for the anti-erosion du- ration of the soil layer . Ye=Zo/E In the formula Ye stands for the anti-ero- sion duration number of a year, Zo stands for the effective soil layer thickness(mm), E is the annual eroded depth (mm/year). In the most of the karst peak-cluster slope in Xichou the soil layer anti-erosion Table 1.12.1 The soil erosion distribution area and the amount of the peak cluster-depression region in the Xichou county. Note: The soil erosion degree index in the table is worked out according to authors works in the karst moun- tains region environment in the southeast of Yunnan, synthesized with Cai Zongxins erosion degree index about the karst area in Guangxi. (1989). Refer to the after mentioned content in the paper and Tab. 1.12.2 I II III IV V VI Erosion grade of intensity no palpable slight middling strong stronger extreme Total erosion erosion erosion erosion erosion erosion Distribution area(km 2 ) 82 45 81 93 27 7 335 Percentage (%) 24.0 17.8 32.0 36.8 10.7 2.7 100.0 Annual eroded modulus (t/km 2 .y) <46 46230 230460 460740 7401300 >1300 Deducted stoneteeth, Average the eroded depth in fact (mm) 0.08 0.35 0.6 0.8 >1.43 0.542 Annual eroded amount (t) 2250 20000 46500 20250 9100 98100 Percentage (%) 2.3 20.4 47.4 20.6 9.3 100.0 Chen Xiaoping The Analysis Research on Soil Erosion Characters ... kitkras1.p65 3.12.98,4:05 128 Black 129 1 year is only 4 - 200 years. They have be- longed to the types of dangerous and ex- tremely dangerous erosions. In some parts of the upper peak-cluster slop the stone- teeth or bed rock exposed completely, and the erosion was in a situation of a dilapidate type. The soil erosion area which has be- longed to the dilapidate type in Guangxi is up to 18,361 km 2 . It occupies 24% of the total area. About making out the erosion degree index which fits the karst area The environment of the karst mountain area has a special character, an especially slow soil formation from the carbonate mother rock, thin soil layer, soil covering discontinuity in the stoneteeth. Although the soil erosion brought about serious harm, the soil erosion modulus is smaller than other non-karst areas in China. In com- parison with the soil erosion degree index standard being sued by the Chinese Minis- try of water conservancy & electric power after 1984, the soil erosion is less than 700 t/km 2 .year in the most areas of the south- ern karst mountain, China. It can be divided into a slight erosion level only (the degree index value: 200-2500 t/km 2 .year). The case is not proportionate to that serious harm- fulness and erosion latent dangerous de- gree of the soil erosion in the karst area which has reached a dangerous-destroying type status. Admittedly, the standard of the karst-soil erosion degree index is needed to be made out again. In 1989 Cai Zongxin es- tablished the theory of corrosion and weath- ering in the carbonate rock, residual non-dis- solution material to form the karst soil, pro- pounded the soil-formed modulus value 68t/ km 2 .year as the minimum allowable soil eroded quantity, and that the five-grade soil erosion index fits the karst area in Guangxi. Used for the reference of the means, in accordance with the actual situation of the karst mountain area in the southeast of Yunnan, taking the soil erosion research area of the western typical peak cluster mountain of Xichou as a sample based on the follow- ing value: the average corrosion rate of 0.0576 mm/y of the carbonate rock in the area, corrosion modulus 155.5 t/km 2 .y, rock specific gravity 2.7 t/m 3 , non-dissolution material of karst rock contents 5%, other mixed rock contents 28%, we calculate that the soil-formed modulus is 46 t/km 2 .y, and considering it as the minimum allowable soil eroded quantity volume. And considering synthetically the relative factors of the slope, vegetation cover, latent dangerous of the soil layer anti-erosion year and erosion action type, referring to the grade difference mul- tiple erosion degree index in the non-karst area, the soil erosion intensity index to the graded six degree was made out to fit the peak cluster karst mountain area in Xichou and southeast of Yunnan (Tab. 1.12.2.). Some scholars discussed the forming process about the weathering crust of the carbonate rock nearby Guiyang (Li jinyang 1991), and propounded the standpoint that mainly the soil-formed action of karst is a different corrosion and selection replace- ment of the underground water, but not the non-dissolution material residual form karst soil in the carbonate rock. However, the problems are still need to lucubrate and understand fully the soil-formed princi- pium, the migratory process of the material and quantitative analyses, etc. Table 1.12.2. Soil erosion degree index in the karst area of Xichou. Note: The erosion grade of intensity referring in the paper is all based on the index of this table. I II III IV V VI Author of Erosion grade tiny slight middling strong stronger extreme degreee of intensity erosion erosion erosion erosion erosion erosion index scheme Soil erosion modulus (t/km 2 .y) Guangxi <68 68-100 100-200 200-500 >500 Cai Zongxin Soil erosion modulus Author of (t/km 2 .y) Xichou <46 46-230 230-460 460-700 700-1300 >1300 the paper Chen Xiaoping The Analysis Research on Soil Erosion Characters ... kitkras1.p65 3.12.98,4:05 129 Black 130 1 Soil erosion types in the karst mountain area In the karst mountain area there is a va- riety of the soil erosion types and the vari- ous erosion types combination. The hydrau- lic erosions such as the surface erosion, gully erosion, swill erosion in the rock in- terval, latent erosion, etc. are the main types; the gravity erosions such as the landslide, rock slip erosion, etc. are the secondary types. Here the typical soil erosion types of the karst peak-cluster of Xichou will be ana- lysed as a sample. Surface erosion. The splash erosion, sheet erosion and slender rill erosion are included. Their distribution area is the most wide in the research area, occupying 50% of the total area. The erosion intensity vary by the action of factors such as the earth- surface condition, precipitation intensity. It includes the scope of a slight, middling and strong erosion grade. Splash erosion. Its distribution is broad at the places such as the crest belt of the upper peak cluster slope and the moun- taintop, a bare soil surface of a part dry-farm- ing terrace land . Although the karst soil has features of a very heavy texture and strong coagulating power, the splash erosion ac- tion is conspicuous, as it is undergone by a rainstorm of a strong rainfall-density, the raindrops kinetic energy is bigger for splashing. The splash erosion causes a mass of soil particles lost stepwise along the slope downwards, so the upper peak cluster slopes and the karst mountaintops can gradually become bare rock conditioned. Sheet erosion. Distributed in the loca- tions such as sparse thicket and not over- grown slopes, straight plowing dry-land on a relatively thick soil layer-repaired terrace land etc. The erosion intensity may reach the middling and strong grade. For exam- ple, at the sheet erosion serious section of the Muzhe mountain and the north peak slope of Dajiechang, the actual measuring intensity is up to 6096 t/km 2 . Rill erosion. Its distribution is mainly at the location such as a slope tilth and a bare surface-soil on the concave part of the peak slope. Generally, the rill density on the slope of the karst mountain area is not so high. It often has the shape of a sparse furcation and intersection. However, it has a relatively high erosion volume. Its erosion intensity is higher than the strong level. Gully erosion. Its distribution is main- ly in the thick-layer soil locations such as the slopes and foot slopes of the peak clus- ter. The distributed proportion in the re- search area is relatively low, but the erosion action is the most serious. The erosion in- tensity often belongs to the stronger and extreme grade. Restricted by the factors of topography and soil layer thickness of the karst peak cluster, its shape can be divided into two main types: shallow gully and in- cised gully. Shallow gully erosion. Generally, in the bare thick soil part of the nether peak clus- ter slope and the foot slope the big current of water has washed the broad and shallow groove gullies side by side. The gully breadth is often 1-2 m, the depth <1m. There is gravel at the bottom of a shallow gully erosion location on the slope nearby the Doukan village of the Bengu town. Incised gully erosion. It is formed by some shallow gullies developed ahead. Its gully-wall is almost erected, gully base reaches the bed rock the stoneteeth has outcropped. The amount and range of the incised gully both is less than a shallow gully. However, the erosion intensity can augment up to an extreme erosion grade. For example, several incised gully devel- oped at the peak cluster slopes in the north of the Benggu reservoir and near the Xiaba wei village, their width is 4 m, and depth 3.5-4 m or the like. Swill erosion in the rock interval. It is a special erosion form in the karst mountain area. Its distribution is on some karst mountain slopes, with a wide stone- teeth outcropping. On the bare surface slopes that have been denuded long, the relic soil in the rock or stoneteeth interval there is still swilled and eroded by a turbu- lent runoff to flow together in the rock in- terval, when heavy rain and rainstorms. But the soil swill erosion is bare when there is a slight and moderate rain, as the rain wa- ter infiltrates mainly in soil. It has the an Chen Xiaoping The Analysis Research on Soil Erosion Characters ... kitkras1.p65 3.12.98,4:05 130 Black 131 1 intensive range of a slight and middling erosion grade, but its harm is so serious that the relic soil is still extinctly eroded until the surface slope becomes a rock desert. Latent erosion. It is a special erosion form in the karst area, too. In some thick- layer soil places of a karst gentle slope land, table land and depression, the same con- formations as a soil cave, blind gully and collapsed hole are formed by the karst la- tent action of the ground water. Typical samples are those big collapsed holes, each eroded soil volume of more than 1000m 3 in the land of the Longtan, Bawei, Shang- jinzu village. Landslide. It often occurs in the belts of local cliff or rock-walls beside highways to be built on steep slopes in a peak cluster. The slope inclination angles of the occur- rence place are often in a range of 60-90. The rock layer vertical joint develops well. The rock and soil is in a latent unstable con- dition. The traffic in some sections of the highway in the research area of Xisaxinjie, Mozhe, Longzheng is stopped, during the rainy season, due to the action of the road cliff avalanche. Rock slip. Its occurrence is lesser and its size is small. On 19 September 1974 a rock slip occurred at a fastigiate-peak hill nearby the Xinqin village of the Fadou town. One carbonate rock layer slid entirely along the smooth slant occurrence from the hill- top to the middle downwards. It is a type of a shallow layer rock slip. The amount of slide is 360m 3 , to heap up the foot slope . A combination erosion type. The main combination types have the following: splash erosion sheet erosion rill erosion slope, splash erosion- swill erosion in the rock interval erosion slope, rillshallow gully erosion slope, shallow gully incised gully erosion slope, sheet erosion shallow gully erosion slope, swill erosion in the rock interval shallow erosion slope, incised gully latent erosion, etc. Due to different erosion conditions on the slope, the distrib- uted variation of each erosion shape is relative higher. The erosion combination type is different in the small drainage areas of each peak cluster depression. Soil erosion occurrence and active regularity Distribution regularity. (1) Accord- ing to the analysis of the occurrence posi- tion of soil erosion types in the karst moun- tain area, surface erosions and gully ero- sions are mainly distributed in the belt with the bare desolation slope where the gradi- ent is more than 25, the sparseness sward, the tilth in the same slope strike etc. Latent erosion is main occurred depression place nearby the underground water belt. The landslide and rock slip erosion occur on the unstable slope position in the local steep rock. (2) According to the analysis of the ero- sion intensity, the erosion intensity varies relatively widely due to the diversity of syn- thetic factors among the ground form, slope, the combination proportion be- tween the soil cover and the stoneteeth, vegetation cover. As a rule, in a good cover vegetation place as a hillside, a step land, there is mainly a slight erosion. In addition, in a place with the slope angle more than 40, bad vegetation, relatively deep and bare soil layer in parts, there is a strong erosion. It may go into a stronger and extreme ero- sion. The middling and strong erosion be- tween the two cases have a widely distribu- tion area, and a maximum proportion of the total erosion volume . Active regularity. (1) Annual seasonal variety of the soil erosion is outstanding. Influenced by the precipitation condition directly, the erosion accord with the strong precipitation activity. The rain is focused to 5-10 months of the rainy season every year. In the rainy season each type of erosion occur widely and strongly. The erosion vol- ume is above 90% of the total in the whole year. (2) The whole soil erosion process is the following: Firstly, the erosion is focused on the peak cluster slope; secondly, the erosion material is deposited at the depression place; lastly, the deposited material is lost into the subsurface system through a latent action of the swallow hole, taking the de- pression as the function of a transfer sta- tion. Chen Xiaoping The Analysis Research on Soil Erosion Characters ... kitkras1.p65 3.12.98,4:05 131 Black 132 1 Soil erosion genesis factor in the karst mountain environment Tectonics and Geomorphology The landform in the karst mountain area, especially in the peak cluster area is undulate ruggedly. The relative height dif- ference in the Xichou peak cluster depres- sion is 100-290 m. The statistics of its slopes angle: the slopes that the angle is greater than 35 are above 82.75% of the total slopes. The slope which reaches the maximum re- pose angle (more than 45, Tab. 1.12.3.) for loose debris and soil, is up to 41.36% actu- ally. It is advantageous for the activity of grav- ity erosion and hydraulic erosion. The research region is located in the northeast of the Wenshan huge rounded rotation and distortion tectonic. It belongs to the uplifting and swelling region from Tertiary. The erosion basis descends widely. Therefore, it provides the physical energy for the erosion activity. The lithologic char- acter of the carbonate rock is mainly hard, pure. The karst formation rate of the soil to the eroded weathering rock is very slow. It will last 17,360 years to weather a thick rock of 1 m, then to form a soil layer less than 10.6 cm. So it makes the anti-erosion fixed number of years of the karst soil very low. Climate condition The average precipitation in the Xichou research region is 1300 mm.y. It is mainly focused in the months from 5-10. The pre- cipitation in the rainy season occupies 83% of the whole year. It is often the spate or rainstorm. From 1962 the rainstorm times occupy 88% of the whole year. The maxi- mum value of the daily precipitation inten- sity is more than 135 mm.date. The maxi- mum precipitation in 1 hour often exceeds 30 mm. According to the field observation data, on the bare slope in the peak cluster with the slope angle of 30 degree with the soil layer water content of 25.3% the initial erosion precipitation is only 5 mm/30 min- utes, the serious soil erosion will occur. Soil factor The karst soil formed by carbonate rock weathering and residua has a character of a heavy texturebad perviousness. According to the sampling analysis in the Xichou peak cluster area, the clay granule (with a radius less than 0.005 mm) content is from 65% to 99% high. This causes it easy to form a rela- tively big soil surface run-off volume. An- other reason is that the anti-erosion action decrease for the reaction by the dry-humid- warm paleo-climate, it is evident that the leaching and chemical weathering function, mainly clay mineral, includes kaolinite and vermiculite; and the soil structure is very close and tight, a strongly expanding and shrinking property, softening and fluidity after the saturated water to form a cylindri- cal shape after an evaporating deaqua-tion. Furthermore, due to the thin soil layer and a smooth contiguity face between the soil and rock, it is very easy to be separated and lost. Vegetation cover condition Forest and vegetation is the essential fac- tor to prevent and conserve a good karst environment. Most of the vegetation in the area like calcite is drought-enduring. Due to the vegetation growth on the rock with an advanced root system penetrating into the rock interval, it has an obvious effi- ciency to prevent the peak cluster slope and anti-erosion. It can be indicated from the experiment observation result of different vegetation slope conditions in the research area. (Tab. 1.12.4.). The vegetation covers rate in the research area decline from 30% to 40.7% in last 30 years. Most of the slope is covered by sparseness bush follow and Table 1.12.3. The statistics proportion of different slope degrees in the Xichou peak cluster area. Slope angle degree <25 25-35 35-40 40-45 45-50 50-55 >55 Proportion of slope amount 11.73 5.52 19.32 22.07 19.31 13.79 8.26 Chen Xiaoping The Analysis Research on Soil Erosion Characters ... kitkras1.p65 3.12.98,4:05 132 Black 133 1 Table 1.12.4. The relationship between different vegetation condition and run-off sand content in Xichou peak cluster research area. Vegetation Initial intensity Run-off sand Observation condition,cover Precipitation precipitation content after 10 min. place proportion(%) Date (mm) (mm/30 minutes) of slope flow (%) Back slope to Higy structure, bush, Broadcasting station shallow, grass, 100 1988.6.27 34.3 16.4 0.022 Measuring High density area I of Huaguoshan Brushwood, 100 1988.6.27 34.3 16.4 0.035 Measuring Spareness bush area II of Huaguoshan brushwood, 40, 40 1988.6.27 34.3 16.4 0.611 Measuring area III of Huaguoshan Bare soil, 0 1988.6.27 34.3 16.4 >2.274 Chen Xiaoping The Analysis Research on Soil Erosion Characters ... bareness slope. It provides a broad space condition for the erosion. Human being factor The karst mountain area has a high-den- sity population, the population density in Xichou is 180.5 person/km 2 . The produc- tion and live style cause more unreasonable activity of destroying forest to plantation plowing, culturing on the steep slope, denu- dation forest for firewood, mining, in build- ing roads leaving around waste residue. It is the main reason of intensifying the ero- sion growth. kitkras1.p65 3.12.98,4:06 133 Black 135 2 South China Karst I Karst Studies in W Guizhou 2 kitkras2.p65 3.12.98,4:47 135 Black 137 2 In order to carry out the Protocol of the first session of the China-Slovenia joint com- mittee for scientific and technological cooperation: the project of Karst Environment Protection and Exploration of Cave Resources was established, a group of three research- ers from the Institute of Geology, Chinese Academy of Sciences (IGCAS) invited by the Karst Research Institute (IZRK) ZRC SAZU visited Slovenia to study on karst caves for two weeks in 1995, paying an official call to the Ministry of Science and Technology of the Republic of Slovenia, IZRK ZRC SAZU and Research Centre, and discussed about further joint research project. The Liupanshui city and its surrounding area were selected as a research area in Guizhou, China. A publication of monograph in English and a round- table scientific conference on the cave genesis in both tropical and subtropical area, the development of cave resources and environmental protection and some contrast research on karst and cave development between the Mediterranean climate area in Slovenia and INTRODUCTION Reseachers from the Institute of Geology, Chinese Academy of Sciences and the Karst Research Institute ZRC SAZU at Yezhong plateau, Guizhou (Photo Shi Mengxiong). kitkras2.p65 3.12.98,8:45 137 Black 138 2 subtropical area in South China have been planned to be realised after finishing the field work. Two scientists from IZRK with Chinese colleagues worked in the karst area of West Guizhou in the same year. Followed by the second session of the China-Slovenia joint research project of Karst Environment Protection and the Development of Cave Resources was signed in September 1996 and a group of three consisting of a researcher from IGCAS with two leaders who are in charge of science and technology and agricultural and envi- ronment of Liupanshui city visited Slovenia with a special subject: The prevention and control of karst desertification and the development and utilisation of cave resources, aiming at a promoting the transformation of desertification in those of poor Liupanshui area. The researcher left there to go on their special work on The carbon dioxide content of air and earth in karst area after visiting group. Four researchers from IZRK worked in Liupanshui area in 1996. The substance of study included as follows: 1. Surveying of the Tianshengqiao-Natural Bridge of Shuicheng, a cave system of Yanzhidong cave and Xiongjingdong cave of Xinchang, Liuzhi, providing scientific basis for evaluating and developing these caves as a resources of tourist scenic. 2. Karst research for carbonate rocks massif in Yezhong, north bank of Beipanjiang river, including a background of geology and hydrogeology, and an evolution and devel- opment of landforms. 3. Making an exploration for the problem of karst desertification, especially for the prevention and cure in the typical victimised area - Taisha, Shuicheng. 4. Making an on-the-spot survey of the profile from Guizhou mountain area with 1000 m a.s.l. to Yunnan plateau 2000 m a.s.l. so as to give a comprehensive understanding of the karst in Yunnan-Guizhou plateau. Along the profile, the karst developed background of some sectors, karstform and landscape and the development of hydrosystem, some well- known show caves and typical karst phenomena, such as Zhijindong cave of Guizhou, the Mabiehe gorge of Xingyi in Guizhou, Lunan Stone Forest and Wolongdong cave of Jiuxiang, Yiliang in Yunnan have been investigated, covering a limits of karst research area at 25 0 20- 26 0 40N and 104 0 -105 0 E. kitkras2.p65 3.12.98,8:45 138 Black 139 2 Zhang Shouyue The Plateau Karst of east Yunnan and west Guizhou Physical Geographic and Geological Setting Physical Geography The plateau karst of East Yunnan and West Guizhou is located at a scope of 24 0 40-26 0 40 N and 103 0 -106 0 E. It is occupied the second grand terrace in the south among the biggest three grand relief ter- races of the giant landform structure in China, Wumengshan and Niushoushan mountain ranges of NNE trend with an el- evation of 2400-2500 m, and some 1000- 2000 m a.s.l. of big basins, which forming the watershed between Jinshajiang and Wujiang rivers of Changjiang river basin and Nanpanjiang and Beipanjiang rivers of Zhujiang river basin. With the strongly uplift of the Qinghai- Xizang plateau since late Cenozoic and the settle of the eastern plain of China, the ba- sic outline of modern landform and the re- gional geomorphologic differentiation were formed. The crustal movements lay a difference of giant geomorphology, the dis- tribution of morphologic units of moun- tains, plateau and basins are controlled and influenced by the geological structures and petrologic properties. The plateau surface in West Yunnan keeps well with 2000 m a. s. l. and less un- 2. 1. THE PLATEAU KARST OF EAST YUNNAN AND WEST GUIZHOU Zhang Shouyue dulating terrain and a relatively height of 100 - 500 m in general, being a middle alti- tude hill and low relief middle altitude mountain. The plateau faces West Guizhou becomes middle relief and middle altitude mountain, and middle altitude hill with an elevation of 1300 1400 m to the Central Guizhou gradu- ally, and reaching 300 - 400 m of a cutting depth on the both side of main river only, show a mountainous landscape. The difference of river levels between Sanchahe river at the upstream of Wujiang river and Beipanjiang river is 500 - 600 m and the distance from incised gorge of Beipanjiang to watershed occupies about two thirds of the distance between two riv- ers (Table 1.). The NE-trending uplift in West Guizhou formed the watershed sepa- rating the Sanchahe river with U-valley and Beipanjiang river with V-valley. It is shown that both sides of watershed have the dif- ferent characters on the neotectonic move- ment. Climate The research area belongs mostly to hu- mid climate of subtropical monsoon type (aridity < 1,0), located in south part of the mid-subtropics. The area has an annual pre- BEIPANJIANG DISTANCE WATERSHED DISTANCE SANCHAHE (m) (km) (m) (km) (m) 1170 (Pingzhai) 17 2300-2400 (Dashan) 11 1650 (Dahebian) 980 (Chahe) 23 200 (Huakouzhai) 16 1590 (Xiabawa) 625 (Shahe) 19 1800-1900 (Duojiao) 13 1150 (Yanjiao) Table 1. The elements of topographical section between Beipanjiang and Sanchahe rivers kitkras2.p65 3.12.98,8:45 139 Black 140 2 cipitation about 1100 - 1400 mm, concen- trating it from May to October and making up 80 - 85 % of the whole year except some 1000 mm of precipitation only on the west edge of east Yunnan plateau. It is a semi- humid climatic area (aridity 1,0-1,5). The regional climate is influenced by dry-cold air current from north and dry- warm air current of Indian continent in winter and spring. Hindered the warm-wet air current from moving to the west by Wumeng mountain range which is on the border of the west part of East Yunnan pla- teau, the west part of research area has a climate of low humidity and less precipita- tion. Most part of the east side of Wumeng mountain area appears a high humidity with plenty of precipitation, forming a pre- cipitation centre of West Guizhou. Geotectonic geology The research area is situated in the south-west part of Yangzi block. Its base- ment consolidated in Late Proterozoic and relatively stable period from Sinnian to Mid- dle Triassic, except fissure eruption of Omei basalt in Late Permian. The Mesozoic and Cenozoic are impor- tant periods for the diastrophism, three strong tectonic movement within slab had been occurred. There was Indochina move- ment in Early Mesozoic, Yanshan move- ment of Jurassic and Cretaceous and Himalayan movement of Cenozoic, having an appearance of mantle fold, lift and basin structure. It is folded and faulted by the strong tectonic movement in Yanshan pe- riod all over China, resulting in overthrust wall by the stress action during the collision and impacting of Pacific, Indian Ocean and Eurasian plates. After the second episode of Himalayan movement in the end of Miocene, a pe- neplain land form was formed and the third episode of Himalayan movement beginning at the end of Pliocene was the tectonic movement of the most great influence upon recent tectonic deformation and geo- morphologic evolution of China. The West- ern China underwent an intense uplift and a continuing uplift of the plane of denuda- tion formed before Quaternary in Eastern China. Reaching a rise scope about 1000 - 2000 m from east to west in the research area, the active Xiaojiang fault in north-south trend was developed in the west of the re- search area, a series of basin structures was developed along the active fault. There are Shuicheng, Anshun, Qujing, Panxian, Yiliang and Luoping sheets in the research area according to the scale of 1 : 200000 geological maps. Stratigraphy In the West Guizhou, the carbonate rocks facies are mainly Carboniferous, Permian and Triassic amounting to several thousand meters in total thickness. Among them, the carbonate rocks of 1715 5644 m is in Shuicheng sheet, 2564 6170 m in Anshun sheet and 1431- 6611 m in Panxian sheet. Before Carboniferous, the area and the thickness of strata cropped out very small, Lacuna completely or partly from Cambrian to Devonian in many regions. Carbonate rocks deposits in the East Yunnan can be found in the strata of Sinian, Cambrian and Devonian to Triassic, the to- tal thickness is relatively reduced than in Guizhou, the thickness of carbonate rocks on Qujing sheet is 1282 - 3373 m, Yiliang sheet 3153 - 3738 m and Luoping sheet 3432 - 4599 m respectively. Dengying group at the upper part of Sinian in the East Yunnan are light colour, sparry dolomite and stromatolite dolomite, being of siliceous in some area. There are Cambrian system with mainly clastic rocks sandwiched in dolomite, Ordovician developed only clastic rocks of lower series about 100 m in thick, middle and upper series of Silurian with clastic and carbonate rocks, light colour thick bed micrite dolomite, breccia dolomite and biolimestone in middle and upper series of Devonian. Carbonate rocks is widely developed in East Yunnan and West Guizhou during Zhang Shouyue The Plateau Karst of east Yunnan and west Guizhou kitkras2.p65 3.12.98,8:45 140 Black 141 2 Carboniferious to Middle Triassic and sepa- rated by noncarbonate rocks, such as clas- tic rocks with coal in the bottom of Carbon- iferous, clastic rocks in the bottom of Permian, Upper Permian basalt and coal series and clastic rocks series at the bottom of Lower Triassic, forming three karstific formations of Carboniferous, Permian and Triassic. Carboniferous of East Yunnan contains coal and clastic series in its bottom, vary- ing in thickness from several metres to over hundred meters, thickness is increasely to the east and changes to contain Carbon- aceous only. Most of carbonate rocks of Carbonifer- ous in the area are limestone with light col- our thick layer, dolomitic limestone with increasing thickness to the east. There are dark colour carbonate rocks with a large number of chert concretion, reaching a thickness of 1500 m in Shui- cheng area. Part of the area has clastic rocks in Lower Permian bottom with coal layer, the thickness ranges from several metres to over hundred meters in the west part and increases to several hundred metres to the east. The carbonate there consists of Qixia group at the lower part and Maokou group on the upper part, Qixia group characteris- ing as a deep colour limestone with chert concretion and about 100 - 200 m in thick, Maokou group with a thickness varying in 200 - 700 m and increasing from west to east mainly with light colour limestone and chert concretion limestone. Basalt in the lower part of Upper Per- mian changes thickness greatly from several ten metres to hundreds and loses in some area, being of 100 - 200 m in thick or even thicker in the coal series and clastic rocks series on the upper part. All the rocks in the lower part of Lower Triassic are sandstone with purplish red and greyish green colours and mudstone with several hundred metres in thick except the east part of Anshun sheet covering micrite with some 500 m in thick and light colour of thin to mid-thick bed. The upper part of the rocks are limestone, dolomite and breccia with several hundred metres in thick. From the bottom to the top of Middle Triassic, there are clastic, limestone and dolomite, varying several hundred meters to thousand in thick and limestone with chert concretion and dolomite on the top. All the continental sediments are scat- tered since the Late Triassic. A plenty of mammal fossils in the middle and Late Pleistocene were sampled in the cave sediments in West Guizhou. There are the most abundant in mam- mal fossils and some cultural excavated from the travertine with light yellow and yellow colours, loam and the breccia at Shilidadong in Panxian. The fossils includ- ing six orders and thirty-nine species are South Chinas Ailuropoda-Stegodon fauna of Middle and Late Pleistocene. Flora fos- sils of Early Pleistocene was excavated in yellow travertine at Dongshan temple in Xuanwei. Pleistocene travertine could be found at the east side of Lunan basin. Karst of the East Yunnan and West Guizhou Plateau Within the scope of six hydrogeological maps as mentioned above, karst area reaches to 24.299 km 2 , occupying 55 % in total area of the maps and varying in size from 35 % to 72 % of the map area. According to the karst zonation of China, the research area belongs to Yangzi block karst area in Porterozoic to Mesozoic carbonate of corrosion and erosion-corro- sion region of tropical and semi-tropical humid climate type. The carbonate rocks system being of same geological time and the same geologi- cal history and the characters of crustal movement, it is of similarities on the karst formation, the karst evolution and the space of rock massif. The differences are determined by some types of karst landscape resulting from the actions of endogenetic and epigenetic forces, some features of karst stage and karst phreatic hydrogeology are represented by the certain karst landscape correspond- ingly. Therefore, three sub-areas are divided according to the types of karst landscape, Zhang Shouyue The Plateau Karst of east Yunnan and west Guizhou kitkras2.p65 3.12.98,8:45 141 Black 142 2 such as East Yunnan (plain-hilly plateau karst), West Guizhou (uvala-qiufeng 1, mountain plateau karst) and Central Gui- zhou (plain- qiufeng and fenglin 2, moun- tain plateau karst) (Zhang et al. 1979). 1. Qiufeng: A type of cone karst which is characterised by gently sloping, hemi- spherical limestone hills, the diameter be- ing times the height. Qiufeng is a translit- eration from Chinese. 2. Fenglin: Tower karst and cone karst - a transliteration from Chinese. East Yunnan karst sub-area The east border from north to south are the line of Longchang, Panguan, Fuyuan, Shizhong along the provincial boundary of Guizhou and Yunnan. The plateau was formed upwarping continuously since the third episode of the Himalayan movement in the end of Pliocene of the peneplain formed in Pliocene. The movement of fault block differences during uplift caused sepa- ration and was out of shape to the pe- neplain, but still remains the character of plateau surface well. The hilly plateau surface with an eleva- tion of some 1800 - 2000 m are distributed mostly, several fault blocks varying in up- lifting scope forming low relief mountain and fault basin. Although an uneven uplift- ing of the crust, the height of separated peneplain was distributed from 1800 m to 2300 m, part of sector reaching to 2600 m and the mountain is similar to the hilly pla- teau surface in morphology, all of them be- ing in wave, only ten to tens meters of the height differences between mountain and valley in shape. At the top of the mountain are relatively gentle with perfectly round shape and few gulch, developing doline and uvala and cov- ering with red crust of weathering on the surface. The area is always appearing karren field on the top of the mountain and hillslope because of the eroded red soil, it is named as the Stone Forest for some higher karren. There are undeveloped hydrographic net on the surface, the underground river system buried not deeply on the surface of hilly plateau, underground river window cave can also be found at the bottom of some dolines, sometimes becoming lakes and underground water of the fault block mountain reaching to a depth of 200 m. Only part of the river at upstream of Nanpanjiang as a base level is the box gorge with a depth about 250 m, and most of the rivers are of a character of light cut plain river, the gradient of longitudinal section in the river bed at upstream of Yiliang is 0,015 %. The aquifers of carbonate in East Yun- nan include Sinian, Devonian, Carbonifer- ous, Permian and Triassic, the total dis- charge of spring occupy over 99 % of all the springs discharging from various aquifers. The limestone aquifer is heterogeneous and Sinian dolomite is homogeneous, being the best water-bearing bed. The aquifer of Triassic distributes as striped for the folded strata in the east part, most of the karstic forms are contact karst form and the pas- sages develop following the strike. West Guizhou karst sub-area The east border along the line of Puding, Liuzhi and Xingyi extending from north- east to south-west. Pliocene peneplain be- comes summit plane because of relatively poor preservation, the elevation of 2000 - 2200 m (Shuicheng) decreasing to 1900 - 1950 m (Panxian) gradually from north to south and about 1700 m a.s.l. in Xingyi area, some mountain with relatively high eleva- tion forming by uplifting of fault block. The character of landform is a step like inclination from NW to SE, the landform is mainly middle relief middle altitude moun- tain. This is because of neotectonic move- ment occurring from regional rift along EN- SW direction, decreasing the uplifting area from NE to SE and therefore, developing the river to SE, a series of water falls were de- veloped on tributaries of Nan- and Bei- panjiang rivers. The underground river de- veloped well with steps by steps and sur- face rivers alternate with underground riv- ers flowing into Nan- and Beipanjiang riv- Zhang Shouyue The Plateau Karst of east Yunnan and west Guizhou kitkras2.p65 3.12.98,8:45 142 Black 143 2 ers and some main tributaries with rela- tively high hydraulic gradient. The former, for instance, Jiulonghe river - Huangnihe river - Nanpanjiang river in Luoping, and the latter, like Daganhe river - Duoyihe river in Luoping and Gesuohe river in Panxian, Wutuhe river in Shuicheng and so on. The landscapes are uvala-qiufeng moun- tain plateau karst, being a typical cone karst area. The positive karst landform is peak cluster with main bottom 100 - 150 m in height, 150 - 200 m in diameter of the peak. The peak cluster consists of peak with a slope more than 45 degree and developed doline among them. The density is about 7- 8 peaks per square km. Depressions and poljes with relatively large scale can be found along the fault or contact zone with noncarbonate, karstification is deep-seated because of incised river, for example, on a plane of denudation with an elevation of 1500 m at the north bank of downstream of Wutuhe river in Shuicheng, the doline with an area of 700 x 500 m and 200 m in depth was developed. Wujiadong cave located in Panlong vil- lage of east Shuicheng has been explored by China-England Speleological team, the cave is over 400 m in depth being one of the deepest cave in China. The area distributes karst aquifers mainly Carboniferous, Permian and Tri- assic, plenty of water occupying 99 % of natural discharge of underground water from various aquifers. The precipitation and surface water coming from noncarbonate recharge the karst phreatic water and drain into river, the water level and discharge are changed with precipitation. The phreatic water table is controlled by geomorphologic factors, the underground water are buried in a depth of 50 - 100 m or 100 m in the mountain, except the depth less than 59 m in some large depressions. The water level is chang- ing strongly, and the fluctuation of dis- charge reaches several tens to hundreds times. The Central Guizhou Karst sub-area Only the west part of the sub-area is lo- cated within the research area, the plane of denudation formed in early Quaternary with an elevation of 1300 - 1400 m and with a smooth terrain, the wave-like landform in the watershed and the height difference between ridges and valleys are only over ten to tens meters. The negative karst forms with large scale distribution are polje and corrosive plain, the positive forms are isolated karst cone with a relatively height of 100 - 150 m and sometimes with hum 20 - 30 m in height, it is one of the typical cone karst types. The area is located at the watershed with strong karstification, the main aquiferous are Permian and Triassic with plentiful karst water resources and smaller buried depth, being of value to develop and utilise. The underground water is recharged from precipitation, the source of the river is formed mostly by underground river draining to polje or karst plain and very few of them draining to Sanchahe river and Beipanjiang river. The underground water has small hy- draulic gradient at Puding, Anshun, Zhen- ning and so on because of the wide and gentle landform, recharging surface river to underground river in raining season, the annual fluctuation of discharge for under- ground river is 3-5 times in general, and the depth of groundwater level are mostly less then 10 m. Zhang Shouyue The Plateau Karst of east Yunnan and west Guizhou kitkras2.p65 3.12.98,8:45 143 Black 144 2 Physical Geography Background Location and Traffic Liupanshui is situated in the western part of Guizhou, bordering on the eastern Yunnan. The area has a geographical co-or- dinate at 25 0 20 - 26 0 55 N and 104 0 40- 105 0 30 E, covering four administrative area of Liuzhi, Panxian, Shuicheng and Zongshan ( Fig. 2.2.1.). The area is 9914 km 2 and with 2.520000 population. It is regions where multi nationalities live in compact commu- nities, including about 640000 in nationali- ties, like Yi, Miao, Buyi, Gelao, Shui, Hui and so on, which occupy some 26 % of total. The Guiyang - Kunming railway and Yunnan - Guizhou road traverse the area, connecting highway between cities and towns. The new constructed Nanning - Kunming rail- way and preparing to construct a railway of Neijiang - Kunming and a road of Panxian - Baise will make the area a hub of commu- nication connecting Yunnan, Sichuan and Guangxi. Geomorphology The area is located in the central of the Yunnan - Guizhou plateau, being a slope zone of transition from plateau to moun- tainous region. The relief slopes inclines gently from NW to SE. Miaoling, the main part of mountainous region in the central Guizhou plateau, is the watershed of Yangzhi river and Zhujiang river. The moun- tains within the boundaries of Liupanshui belongs to Wumeng mountain area, having 2.2. THE KARST ENVIRONMENT AND CAVE RESOURCES OF LIUPANSHUI AREA , GUIZHOU Shi Mengxiong, Zhang Shouyue several tens mountain peaks with 1700 - 2700 m a.s.l.. The highest in this area is Jiucaiping with 2900 m a.s.l. from north to south, bordering provinces for Yunnan and Guizhou generally. Plateau landscape with smooth terrain is in the west of 2000 -2500 m a.s.l., mountainous region landscape of 1500 - 2000 m in the east, except some ar- eas keeping smooth plateau surface and other mountains becoming fragmented for cutting strongly by the river. River system Shuicheng is located in the watershed of Yangzhi river and Zhujiang river, so apart from Sancha river in NE part belongs to Wujiang river system, other river within the area are tributaries of Nan & Beipanjiang rivers - the main river of Zhujiang river sys- tem ( Fig. 2.2.1.) . Liupanshui area is rich in water resources, according to incomplete statistics, there are 71 rivers with a length of over 10 km, and 14 of them belong to Wujiang river system, 57 for Zhujiang river system of which 44 rivers belong to Bei- panjiang tributaries including rivers from north of Yizikong, Laochang and 13 rivers from south belong to Nanpanjiang tributar- ies (Fig. 2.2.1.). The rivers with an average slope of 0,006 - 0,011 are relatively less at up stream and increasing obviously at down. stream in which the deep cutting val- ley even reaching to 300 - 500 m, and 1000 m the deepest. The valleys always appear v type or box-like with underground flow and waterfall. According to the observation data from hydrostation, the average annual Shi Mengxiong, Zhang Shouyue The Karst Environment and Cave Resources ... kitkras2.p65 3.12.98,8:45 144 Black 145 2 Shi Mengxiong, Zhang Shouyue The Karst Environment and Cave Resources ... Fig.: 2.2.1. Drainage system and location map run off of Beipanjiang river is 140,1 m 3 /s. The largest discharge appears in June to September with the extreme value of 2540 m 3 /s. and the minimum discharge is in March and April with an extreme value of 20,4 m 3 /s, and ordinary tributary have an average annual runoff about 10 - 25 m 3 /s. Surface water and underground river al- ways show a phenomena of replacement, this is also one of the characteristics of karst rivers. In general, rivers in the area have the features of strong abilities in deep cutting, large gradient and rapid current velocity. kitkras2.p65 3.12.98,8:45 145 Black 146 2 Climate Being in subtropical zone, the climate is of humid and temperate overcast and raining. The average annual temperature is 12 - 15 0 C, maximum 20-22 0 C (July) and minimum 3 - 6 0 C (January) . The climate is influenced by landform greatly because of the mountainous region with higher in NW and lower in SE, having obviously a vertical zonality. There are climate zones divided by elevation and meteorological factors. ZONE ALTITUDE AVERAGE ANNUAL TEMPERATURE warm 1000-1500 m 18 - 14 0 C cool 1500-1900 m 14 - 12 0 C cold > 1900 m < 10 0 C with soluble and insoluble rocks and have a shape of bands appearing in turn. Con- trolled by tectonics, karstification always developed the some direction with tec- tonic lines showing distribution of a shape of bands. According to the direction of tectonics line, the area can be divided into two dif- ferent tectonic belts. The boundary is from Weining - Suicheng - Liuzhi districts, hav- ing Weishui NW tectonic belt with single stable tectonic line on the north and Puan tectonic belt with complex tectonic line to south. 1) Weishui NW tectonic belt with 250 km length and 40 km wide is composed of several parallel faults and of a series brachy - anticlinal and synclinal folds among them, a longer major tectonic is Weishui anticline and Duoque anticline with carbonate rocks of Carboniferous as a axis and Baixing syncline with carbonate rocks of Low Triassic as a axis. The axial of Weishui anti- cline is 290 0 - 310 0 , extending about 50 km with tight fold and slowly at NE wing and steep on SW wing. Duoque anticline ex- tends about 100 km, 10 km wide, with a middle to steep dip angle, developing large faults paralleled the run of the formation. The watershed of Sanchahe river and Beipanjiang river inclines through the anti- cline. Baixing syncline is an arrested syncline. Wuliudaxiaodong is located the Xinchang massif between the syncline and Duoque anticline. Weichong syncline with a axial of NE, the stratum at core is Jurassic being slowly at NW wing and unsym- metrical anticline with steep SE wing. Suicheng natural bridge was developed in carbonate rocks of NW wing Lower Triassic. 2) Puan tectonic belt: It is an belt of strong interweared tectonics with NW, NE and NNE. Faer tectonic basin is composed of folds and thrust faults, reflecting a multi - direction structure of comprehensive ac- Shi Mengxiong, Zhang Shouyue The Karst Environment and Cave Resources ... Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Liuzhi 15 20 30 100 170 300 279 210 150 140 40 20 Panxian 18 22 29 54 176 277 242 250 183 125 38 17 Shucheng 18 20 21 68 137 236 223 191 150 107 39 17 Table 2. Precipitation (mm/month) in Liupanshui area. The great changeable climate character, soils and vegetation in the zones make some difference seasons between appearing al- ways midsummer in the valley and cold air in the mountain. The average annual pre- cipitation in the area is over 1000 mm and have a pattern of decreasing from east gradually, but conversely, the evaporation. From May to October there will be rain- ing season in the area, occupying the rain- fall of over 80 % of the year, and dry season from December to next March with about 7 % of rainfall. Tab. 2 shows the meteoro- logical factors. Tectonics and Hydrogeological Setting Tectonics Liupanshui area belongs to the west part of Yangzhi block, it is situated in west Guizhou massif along the east side of Sichuan - Yunnan tectonic zone. The tec- tonics is mainly linear fold, interbeding kitkras2.p65 3.12.98,8:45 146 Black 147 2 tion, having 9 folds over 10 km and 11 faults. Houchang anticline is situated in south part of Faer tectonic basin, axial 325 0 . The stra- tum of core part is Mid - Upper Carbonifer- ous with slowly rock bed at both wing and dip angle 10 0 - 20 0 . Guniuhe anticline is an important part of Puan tectonics, with tight fold extending to north - south about 50 km, composing of carbonate rocks from Per- mian to Devonian. Yizikong syncline and Lianhuashan anticline are main tectonics, these folds are composed of carbonate rocks in Permian and Triassic and a little in Devonian and Carboniferous. Shi Mengxiong, Zhang Shouyue The Karst Environment and Cave Resources ... Fig.: 2.2.2. Sketch of structural geology of Liupanshui kitkras2.p65 3.12.98,8:45 147 Black 148 2 Shi Mengxiong, Zhang Shouyue The Karst Environment and Cave Resources ... Fig.: 2.2.3. Lithostratigraphic columns of Panxian, Shuicheng and Liuzhi kitkras2.p65 3.12.98,8:48 148 Black 149 2 Aquiferous Formations The karst water is the most important water resources. The karst water also can be divided into three sub - types by the lithological characters. 1. The conduit water in carbonate rocks The kind of this waters distribute widely, aquifers formations including Lower Permian (P1) and Carboniferous (C) , Middle Triassic (T2) and lower Triassic (T1yn) in Panxian and Liuzhi. A. Middle Triassic (T2): including Falang group (T2f) and Guanling group (T2g2+3), the lithologic character is mainly mid-thick bedded limestone, argillaceous limestone and dolomite distributed, most of them in a arrested syncline rich in water resources with more than 150 l/s discharge of springs. B. Lower Triassic Yongningzhen group (T1yn) distributes at the wing of syncline, consisting of thin to mid - bedded lime- stone, marl, shale, dolomite intercalated with gypsum and breccia, having total thick- ness from hundred to hundreds m. C. There are widespread for lower Permian (P1), including Qixia group (P1g) and Moukou group (P1m), thick bedded limestone and black marl sandwiched at the bottom with a thickness of hundreds to thousand. The discharge of spring is about 150 l/s in average. The group have a favour- able condition of storing underground wa- ter for the tectonics and landforms charac- ters, rich in underground water. D. Carboniferous (C): There are mid thick bedded limestone on the upper, thick bed massive of dolomite. Limestone and dolo- mitic limestone in the middle part, thick bed massive limestone at lower part, some layer with flint and strong karstification, the springs with a discharge of about 70 l/s. 2. The fracture - conduit water in karst carbonate rocks intercalated with clastic rocks The group consists of three aquifers, in- cluding Middle Triassic (T2) Falang group (T2f) and Guanling group (T2g2+3), Lower Triassic, Yongningzhen group (T1yn), and Lower Carboniferous to Middle Devonian (C1 - D2-3). The two former groups belong to fracture - conduit aquifer only at Shui- cheng. Lower Carboniferous to Middle and Upper Devonian (C1 - D2-3): The lithologic characters in Shuicheng and Panxian are mid - thick bedded argillaceous limestone, marl, limestone intercalated with siliceous rocks, flint layer, shale and basalt of 0,8 m on the top, total thickness of hundreds to thousands without so strong karstification but well developed fracture for flowing out springs with average discharge only 3 l/s. 3. The karstic fracture water of clastic rock intercalated carbonate rocks A. A transition layer of Upper Carbonif- erous to Lower Permian (C3 - P1): The aq- uifer distributed in the boundary between Shuicheng and Panxian only, mainly with sandy shale and silicarenite interbedded with limestone, argillaceous limestone and marl of total thickness about 900 m ,with less karstification and undeveloped frac- ture, so less spring. B. Middle Triassic Guanling group (T2g1): Only one aquifer in the lower part of Guanling group in Panxian and Liuzhi. The lithological features are mudstone, shale interbedded with argillaceous lime- stone and dolomite. Tianshengqiao - Natural Bridge and Cave System In Shuicheng The geomorphologic unit of area be- longs to the low relief ( 200 - 500 m ) mid- dle altitude ( about 2000 m ) mountain. Situated at Ganhe village, about 80 km NE from Liupanshui city the tributary of Daganhe river cut here deeply with a strike of NW - SE and the natural bridge crosses above the valley from NE to SW. The bridge surface become a part of the country road between Ganhe and Yantoushang villages. The bridge surface was measured 30 m in both of the length and wide, 15 m of thick- ness for rock stratum of the roof, 1861m of Shi Mengxiong, Zhang Shouyue The Karst Environment and Cave Resources ... kitkras2.p65 3.12.98,8:48 149 Black 150 2 elevation from the bridge surface and 1725m from the bottom of the valley, form- ing a height of 136 m from bridge surface to the bottom. It may be the highest one. There are several caves and small natural bridges around the bridge within an area of 1 km 2 . Geological setting Natural bridge cave system Developed in carbonate rocks of Lower Triassic Yongningzhen group (T1yn3) (Fig. 2.2.4.), the bottom of the bridge is seated on the lower part of T1yn3, the rocks are mid - thick bedded grey - purpose marl about 30 m in thickness. The natural bridge cave sys- tems tectonic is at NW wing of Weichong syncline. It is an unsymmetrical syncline, ap- pearing gentle on NW wing with a dip 10 0 - 20 0 and steep on SE wing with a dip some 60 0 - 80 0 (Fig. 2.2.4.) The natural bridge cave system and its formation Natural bridge is developed in the main dry river of the tributary on the west of Daganhe (Fig. 2.2.5.), the total length of the main dry tributary is about 2 km, and the bridge is on the mid stream. Two small natu- ral bridge at down stream and 300m far from the Daganhe, some 1620 m of eleva- tion at the bottom. Yanzidong cave is a large horizontal cave in research area. The cave situated on the south of natural bridge is a resurgence with elevation of 1725 m. The cave was surveyed 50 m in high and 500 m in length, the most narrow part in cave is less than 10 m and Shi Mengxiong, Zhang Shouyue The Karst Environment and Cave Resources ... Fig.: 2.2.4. Geological map and section of Tienshengquiao area kitkras2.p65 3.12.98,8:48 150 Black 151 2 Shi Mengxiong, Zhang Shouyue The Karst Environment and Cave Resources ... Fig.: 2.2.5. Landform of Tienshengquiao area kitkras2.p65 3.12.98,8:48 151 Black 152 2 Shi Mengxiong, Zhang Shouyue The Karst Environment and Cave Resources ... widest one 40 - 50 m, the section of cave mouth shows an unsymmetry key hole like and down to underground after running out about 100 m and appears again some 300 m then gathering to the tributary, and then underground again and again and draining to Daganhe toward to the east. The cave developed in the 4th section of Lower Triassic Yongningzhen group (T1yn4) with dolomite of light grey, thin to mid thick argillaceous dolomite, limestone and breccia. The dip of layer is SSE with angle 20 - 25 0 . Being controlled by the frac- tures, the cave system especially the older phreatic gallery at right side of ground river shows a chessboard like in plan. Karst of Yezhong massif Both west and east sides of the massif are watershed consisting of Upper Permian basalt. In the north, the watershed is landform and the clastic rocks of the bot- tom of Lower Permian. The boundary of underground water should be the diabase in Lower Permian thick bedded massive limestone with a thickness of 600 m and flint limestone with gentle formation and a dip about 7- 10 degree. Its karstification is controlled by clastic rocks with 150 m in thick at the bottom of Lower Permian(P1L). The massif lies to NE wing of Houzi- chang anticline, the axis is NW 325 0 and rakes to the west, the strata of core is Mid- Upper Carboniferous thick bedded lime- stone, the Beipanjiang valley developed along the axis, some big discharge and hot springs emerge from the river along NEE- trending fault in Carboniferous limestone. The carbonate rocks massif hanging high above the base level is the cleuch dis- section developing along the fault without big discharge springs and caves along the clastic rocks (P1L), the massif has been in the vadose zone. A few depressions could be found in the hinterland of the massif with an elevation of 2000 - 2100 m at the bottom and 200 - 300 m in diameter and the deepest one about 70 - 80 m. The area is a typical cone karst landscape, the elevation on the peak top is some 2100 - 2200 m and 50 - 60 m in height of cone in general with a top angle of 110 - 130 0 . The evolution of geomorphology can be divided into three phases by the analysis of the plane of denudation. The first phase of denudation plane is composed of cone peaks and depressions or dolines at an elevation of 2100 - 2200 m. The second one is wide valley formed of undercutting on the first plane with 1600 - 1800 m a.s.l. which con- sisting of a series of poljes and being of per- manent or interval surface water. The third one is Beipanjiang gorge, the gorge was formed by the river from the plane of denu- dation about 1500 - 1600 m a.s.l., undercut- ting with a depth of 700 - 800 m. Tourist resources of karst and caves Carbonate rocks distributed almost all the Guizhou province except south - east- ern part, it is one of the typical karst area in Fig.: 2.2.6. Geological sketch map of Yezhong massif. kitkras2.p65 3.12.98,8:48 152 Black 153 2 Shi Mengxiong, Zhang Shouyue The Karst Environment and Cave Resources ... Fig.: 2.2.7. Geomorphological map of Yezhong massif kitkras2.p65 3.12.98,8:48 153 Black 154 2 Shi Mengxiong, Zhang Shouyue The Karst Environment and Cave Resources ... south China. . There are second large cham- ber in the world of Miaoting with an area of 117,000 m 2 in Gebihe cave system of Ziyun county and some cave exploring area of Shuanghedong cave in Suiyang county with several km in length, besides the opened noted tour area like Huangguoshu waterfall, Longgong and Zhijindong cave. Liupanshui area is a potential tourism area not only developing various karst Landforms but also rich in underground karst formations, remaining to be devel- oped for promotion of economical condi- tions. The synopsis of the natural scenery in Liupanshui area as follows: 1. Natural Bridge of Shuicheng: As men- tioned above, it is the highest highway bridge, with 136m in height, so far all over the world. 2. Doline of Huagaxiang, Suicheng: A huge doline about 3 km from NE of Huaga- xiang in SE of Shuicheng is of exploring value, its upper edge lies at 1420 - 1480 m a. s. l. and with a diameter of 250 m at the bottom and an elevation of 1225 m, only 1,25 km far from the Wutuhe river gorge with 800 m a.s.l of river level. The area of doline are 500 x 700 m. 3. Wuliudaxiaodong cave at Xinchang massif of Liuzhi: It is a large cave system, similar to Mammoth cave of USA in geologi- cal settings, being of a potential exploring base. At the area distribute mudstone and marl in the middle part of T1yn1 with a wide spread outcrop for a smooth occur- rence, covering two underground rivers and Wuliudaxiaodong cave. Therefore, the character of karstification under the mas- sif is a cave system developed in a smooth carbonate rocks under the mudstone. 4. Yegoudong ( Feilongdong ) cave at Xiongjing of Liuzhi: The cave is developed in limestone of Lower Permian ( P1m ) with a dip 25 0 - 30 0 , measured length 600 m. Plen- tiful speleothems make the cave more at- tractive. Besides growing stalagmite and stalactite, there are drapery, straw, and helictite formed by dripping and spray water. The cave with convenient traffics is a valuable undevel- oped show cave. 5. Danxia mountain and Biyundong cave: It is an ancient historical scenic place. Xu xiake - the famous geographer in Ming Dynasty had explored here and gone down in his book Travels of Xu xiake. A small temple on the Danxia mountain where Xu had been lived. Biyundong and Shuidong caves at SW end of Panxian polje are famous touring site with about 26 carved stone on the both inside and outside the cave, the cave has been arranged as a park and joined in International Show Caves Association (ISCA) in 1995. 6. Beipanjiang is a magnificent undevel- oped valley, with several hundreds meters deep, much more tourism resources are waiting for use. Karst geological disaster Geological disaster like earthquake, de- bris flow, earth slide, subsidence, collapse, soil erosion and so on are the productions under specified geological environment. The soil collapse, flooding and deserti- fication are primary geological disaster in karst area because of unique landform, lithological characters and its properties of development and distribution. Soil collapse The soil collapse occurs mainly in Shuichengand Panxian, especially project- ing in Suicheng polje. Suicheng polje presents NW - SE sur- rounded by mountains, lower in the mid- dle with a length of 28 km and 2 - 3 km wide, developing well in basins fault structure about 80 faults with various size, NE 60 0 , NW 290 0 of fracture and bedding plane . Soil collapse is a direct hateful result for increas- ing of industries and industrial population consequently rapid supply of industrial and living water and over extracted under- ground water especially in dry season, caus- ing large extensive descending of ground- water level then soil collapse. There are over 700 soil collapse sites with various size near Laizhidong cave area of the polje kitkras2.p65 3.12.98,8:48 154 Black 155 2 within 2 - 3 km 2 , and some destroyed house and farmland threaten the safety of human being and domestic animal. Another reason of soil collapse may be very thin (< 10m) Quaternary overburden in Shuicheng polje, It is surveyed that the area with overburden >10 m occurs no soil collapse. In Putian of Panxian, three new collapse dolines are formed after flooding, one of them become a karst pond because of gath- ering water for long time. Another example at Jichangping of Panxian, there are fissures near terrain when pumping test and stop pumping for the safety of houses. Shi Mengxiong, Zhang Shouyue The Karst Environment and Cave Resources ... Fig.: 2.2.8. Distribution of soil collapse and flooding of Liupanshui kitkras2.p65 3.12.98,8:48 155 Black 156 2 According to the project, well devel- oped karst fissures and caves with a diam- eter 2 - 4 m, the ground water level have fallen 24 - 39 m after pumping and a lot of silt was brought about then the surface soil collapse was occurred. The controlled factors of surface soil col- lapse in karst area can be summarised ac- cording to the examples mentioned above: 1. Karst fissures in subterranean: A size of soil collapse area and space can be lim- ited by developed caves. 2. The factors of motive force resulting in soil collapse are over extracted under- ground water and built reservoirs causing rapid change of the level of underground water. 3. The thickness of an overburden is also an important condition. ( Thickness value is determined by the geological condition.) Flooding A relatively high frequency hazard of drought or waterlogging in Guizhou pla- teau was figured about 20 %. Karst basins Shi Mengxiong, Zhang Shouyue The Karst Environment and Cave Resources ... and depressions in Liupanshui area are al- ways flooding caused by torrents of water rushed down the mountain, failed to drain the waterlogged land or remove water to caves impeded from these basins and de- pressions in raining season. A series of karst basins and depressions with different sizes which can be calculated a size 500 m ( 33,4 ha ) are some 50 - 60 in Liupanshui area. Another kind of basin dis- tributing in alimentation area of under- ground water and near the watershed are normally drought for most of the precipita- tion flowing into deep of subterranean along the karst fissures. Some depressions distributing in draining area for concentrat- ing karst water and surface water are always flooded because of full and block up of terra rossa or humus in fissures and dolines, the flooding duration are lasted 1 - 2 months even half a year. Desertification The research area is one of the serious area on desertification in Guizhou. The area Fig.: 2.2.9. Deforestation, soil erosion and desertification in the Taishaba area (Photo A. Mihevc). kitkras2.p65 3.12.98,8:48 156 Black 157 2 of carbonate rocks and area of soil erosion reach to 8865 and 6151 sq.km, occupying 89,42% and 62,04% in total area of Liupan- shui respectively. The arable land with a slope more than 25 degrees take up to 13. 78 % and 38500 ha in total arable land. Taisha - the typical area of desertification is seated on the plane of denudation of 2160 - 2220 m a.s.l.. The Lower Permian carbon- ate rocks is distributed at the core of anti- cline with NW 330 trend of axis. It is lo- cated on the watershed of both tributaries of Beipanjiang river. On the plane of denudation, the positive karst forms are qiufeng - a type of cone karst. The limestone hills are 60 - 80 m high and 110 - 135 degrees of the angle on the hill top. The negative karst forms are shal- low plate-shaped doline or uvala with 20 - 30 m in depth. It is bare karst hill without any soil and vegetation except karren. The water table lies down more than 100 - 200 m. The following treatments have been taken to change the poor economical situa- tion: 1. Emigrating locate people to non- carbonate rocks area with lower elevation; 2. Reforestation for water and soil con- servation and reducing arable land; 3. Terracing of the mountain slopes to prevent the soil erosion. Fig.: 2.2.10. Land use on karst surface in W Guizhou. Terrasing of the slopes can prevent soil erosion (Photo A. Mihevc). Shi Mengxiong, Zhang Shouyue The Karst Environment and Cave Resources ... kitkras2.p65 3.12.98,8:48 157 Black 158 2 The characters of karst water records the process in evolution of natural water and provides information for making a through study on the formation and evolu- tion of caves, and the velocity of karstic denudation. It is also the basis of the pro- tection and valuation for ecological envi- ronment. The data discussed on water analysis were collected from field and tested during the expedition in 1996. Parameters, methods of water analysis and equipment To conform to the special purpose of speleological exploration, the principle of choosing methods and equipment for natu- ral water analysis in the field are portable and convenient to use, fast and accurate enough to obtain the parameters needed. 2.3 HYDROCHEMICAL PROPERTIES OF KARST WATER IN LIUPANSHUI Jin Yuzhang The table shows parameters tested, meth- ods and equipment used and their precision concerned. Description of the water samples and data The number 9611201 was sampled from the resurgence of Yanzidong cave at Ganhe natural bridge. No.9611262 is the water from epikarst aquifer sampling from a wa- ter tank at Taisha village, which is located on the core of the anticline with NE-SE di- rection near the watershed and the typical area of karst desertification with very thin of soil bed. The samples 9611284 and 9611285 are lied on the valley from Chang- ming to Yezhong, finding clastic rock with coal P1L at the bottom of the valley with a dip angle some 7, covering carbonate rocks massif P1q+m on both side of the valley. It Jin Yuzhang Hydrochemical Properties of Karst Water in ... PARAMETERS METHOD WITH EQUIPMENT PRECISION Temperature ( 0 C) HACH company + 0.5 0 C Conductivity (s/cm) Model 44600 0.1s/cm Total dissolved solid (mg/l) Conductivity/TDS Meter 0.1mg/l pH Digisense pH Meter, Model No. 5994 +0.1pH+1count CO 2 in air (mg/l) Gastec Sample Pump 5-10 % HACH Digital Titrator Model 16900-01 Dissolved CO 2 (mg/l) Titration Cartridge (NaOH) + 1 % HCO 3 - (mg/l) Titration Cartridge (H 2 SO 4 ) + 1 % SO 4 2- Titration Cartridge (EDTA) + 1 % Cl - (mg/l) Titration Cartridge (AgNO3) + 1 % Ca 2+ Titration Cartridge (EDTA) + 1 % Mg 2+ Titration Cartridge (EDTA) + 1 % TH (H 0 ) Titration Cartridge (EDTA) + 1 % Aggressive CO 2 (mg/l) Titration Cartridge (H 2 SO 4 ) + 1 % Table 1. Parameters, methods and equipment, and the precision of water analysis kitkras2.p65 3.12.98,8:49 158 Black 159 2 is one of the type of contact polje. Sample No. 9611286 is a karst spring at the low reach of the valley with a discharge of 2,4 l/ s. The 9611287 comes from a small moun- tain valley on the east part of Yezhong mas- sif, perch ground water formed by resist- ing of argillaceous sandwiched in a gentle Permian carbonate rocks with very small discharge and never dried up, collecting in a water tank for daily life. The place is 150 m higher than that of main valley. Physical properties and chemical com- positions of the water samples mentioned above are listed on the table below: PARAMETER RESURGENCE EPIKARST PERCHED water tank water tank water tank spring WATER TANK Sample No. 9611201 9611262 9611284 9611285 9611286 9611287 Aquifer T1yn2-4 P1q P1q P1q P1q P1q T( 0 C) 9.7 8.0 10.2 15.3 16.4 pH 8.25 8.41 8.54 7.64 8.14 8.55 CND(s/cm) 190 320 107.3 600 342 328 TDS(mg/l) 95 159 53.7 300 171 165 TH(H 0 ) 5.25 8.04 5.56 16.42 8.94 9.83 Ca 2+ (mg/l) 36.00 56.80 18.40 113.60 64.00 66.40 Mg 2+ (mg/l) 0.98 0.49 13.18 2.44 0 2.44 HCO 3 - (mg/l) 97.60 170.80 61.98 251.32 178.12 180.56 SO 4 2- (mg/l) 0 3.82 15.28 68.40 7.64 1.91 Cl - (mg/l) 4.80 7.20 5.20 18.40 24.00 6.80 DCO 2 (mg/l) 0.60 16.80 4.80 2.60 6.00 1.60 ACO 2 (mg/l) 0 0 6.36 0 0 0 Table 2: The physical properties and chemical composition of karst water in Shuicheng, Guizhou AQUIFER PANXIAN SHUICHENG ANSHUN pH TDS(mg/l) TH(dH 0 ) pH TDS(mg/l) TH(dH 0 ) pH TDS(mg/l) TH(dH 0 ) T2g2+3 7.1 189.90 8.52 8.2 547.68 20.72 T1yn 7.4 116 5.71 7.1 140 7.74 7.9 209 10.06 7.6 480 21.77 P2b 5.6 33.14 0.50 6.8 29 0.64 7.3 8.48 8.3 300.43 15.48 7.6 116 4.28 7.7 18.30 P1m 6.7 120.65 6.05 7.5 119 6.22 7.3 - 100 4.88 7.9 276.05 12.71 7.8 189 9.985 7.6 210 11.19 P1q 7.8 190 9.60 8.4 280 13.30 C3m 7.5 147 8.17 7.3 160 8.42 7.7 194 10.43 7.7 18.30 C2h 7.2 160 8.84 7.9 22.90 C1 7.4 155 7.55 7.8 227 11.54 Table 3: The parameters of TDS and TH from basalt and karstic aquifers Jin Yuzhang Hydrochemical Properties of Karst Water in ... The water types in carbonate area are mostly HCO 3 - - Ca 2+ , Mg 2+ or HCO 3 - - Mg 2+ . Ca 2+ patterns according to the maps of hydro- geological survey (1 : 200000). The parameters of TDS and TH from ba- salt and karstic aquifers by each map sheet are listed on the table. Discussion 1. No. 9611201 was sampled from the cave on the water table, but contains low ions concentration, it was probably got af- kitkras2.p65 3.12.98,8:56 159 Black 160 2 Jin Yuzhang Hydrochemical Properties of Karst Water in ... ter heavy raining and the water coming from the cave of an allogenic water and with less length. 2. The numbers of 9611262, 9611286 and 9611287 are similar in contents, the latter two samples proved the quantities of typical karst water in Yezhong massif. It is a massif without water, which is suspend- ing highly above the Beipanjiang gorge and set off by the underlying P1L aquiclude, because the ground water of the massif is drained by the main valley developing along a fault and branches and found nothing about good spring. Therefore, there is no spring with high discharge in karst valley which incises the massif, and the composi- tion of the perch ground water or spring with converging water locally is quite closely with the epikarst water sample No.9611262. 3. No. 9611284 is taken from the water tank of the diversion works, the water sources is probably from the surface. 4. The TDS, TH, CND, Ca 2+ and HCO 3 - contents of No. 9611285 are much more higher than the others, only a few water samples are similar with it in the past stud- ies, it is probably related to coal mining in P1L and polluted by the waste water of daily use according to the data of low pH value and high concentration of SO 4 2- . 5.The contents of TDS, TH and pH of karst water area are higher than those of the water in basalt. kitkras2.p65 3.12.98,8:56 160 Black 161 2 Introduction Tianshengqiao - Natural Bridge is situ- ated near the Ganhe village, about 80 km NE from Liupanshui city, NW Guizhou. Bridge is the last remain of once larger cave system of the Ganhe river. Its arch is 15 m thick and 136 m high. There are several caves in vicinity, Swallow cave being the largest of them. 2.4 SPELEOLOGICAL EXPLORATION AT TIANSHENGQIAO - NATURAL BRIDGE, SHUICHENG Franci Gabrovek, Andrej Mihevc, Bojan OtoniŁar, Nadja Zupan Hajna During November 1996, group of re- searchers from Slovenia and from China worked in the area of Tianshengqiao - Natu- ral Bridge. About 2 km 2 of the area was mapped and three caves were explored and surveyed (Gabrovek et al., 1997). Some measurement of main structural elements on the surface and in the caves were done. Wa- ter, rock and sediment samples were taken for further lithological and x-ray analyses. F. Gabrovek, A. Mihevc, B. OtoniŁar, N. Zupan Hajna Speleological Exploration at Tianshengqiao ... Fig. 2.4.1. Tianshengqiao natural bridge area with caves. kitkras2.p65 3.12.98,8:56 161 Black 162 2 Geomorphology The area of the natural bridge Tian- shengqiao is situated on the southern slopes sweeping from the elevation of 2300 m towards the valley of the Daganhe river in elevation of about 1600 m. The surface is well karstified, but shows surface fluvial forms, shallow fluvial valleys, canyons, among which the deepest is the canyon of the Ganhe river, which flows un- der the natural bridge. Doline and closed depressions are on the edge of the plateau only. On the slopes they are only along the rivers, which formed the Tianshengqiao and along the river flowing from the Swal- low cave. These depressions are elongated collapse depressions, with steep or vertical walls developed from the disintegrated cave system. On the upper part of the slope in about 140 m deep canyon of the Ganhe is cut. In upper part the canyon is formed in lime- stone, in lower is more marly limestone. Canyon developed from the sinking river cave which ceiling remained only one place as the natural bridge Tianshengqiao. The altitude of the bridge is 1861 m a.s.l., bridge is about 15 m thick and 30 m wide. It is used for the road connection of the vil- lage Ganhe and Yantoushang. From the bridge to the river bellow is 136 m. Geology The area belongs to transitional slope of the Yunnan Plateau to Guizhou plateau, which is folded belt composed of a series synclines and anticlines (Maire, Zhang & Song, 1991). In the wider vicinity of the investigated area few hundred to thousand metres thick packages of carbonate, silici- clastic and basalt rocks from Middle Carbon- iferous to Lower Jurassic in age are present (Zhang & Walthman, 1985). Lithology The caves and the natural bridge are de- veloped in dark-grey middle and thin bed- ded to platy somewhere laminated Lower Triassic micritic limestones and marly lime- stones with intercalations of marls and dolomites. Among allochems bioclasts pre- vail. The most frequent are molluscs (espe- cially gastropods) and ostracodes, in ripples also crinoides. The rocks are characteristi- cally bioturbated and somewhere show mottled structure. Beds often contain clayey dissolution seems and stylolites as well as isolated ripples and laminas mainly of bioclasts. In some places desiccation cracks were noticed. In thin sections pyrite framboids and concentrations of organic matter are visible. We can conclude that carbonates were deposited in shallow more or less restricted inner part of the carbonate shelf sea where sometimes higher energy events occurred. Occasionally terrestrial influence is evident. Somewhere desiccation cracks indicate emersion conditions. F. Gabrovek, A. Mihevc, B. OtoniŁar, N. Zupan Hajna Speleological Exploration at Tianshengqiao ... Fig. 2.4.2. Tianshengqiao natural bridge (Photo: A. Mihevc). kitkras2.p65 3.12.98,8:56 162 Black 163 2 Structural elements of the limestone and dolomite beds In the area beds generally dip toward S- SE, measured directions of dips are from 160 0 to 170 0 , with dip angle from 20 0 to 25 0 . Frequency of fissure directions is shown by intensity and length of bars in a rosette (Fig.2.4.4.). The most expressed di- rection of faults and fissures is about 90 0 - 270 0 (E - W). The second place occupies the direction is about 0 0 - 180 0 (N - S) and the third one is direction 45 0 - 225 0 (NE - SW). Cave system, the morphology of the channels in the caves and collapse depres- sions between them are strongly related to directions of all three main faults and fis- sures directions (Fig.2.4.5.): 1. E-W, 2. N-S 3. NE-SW. The main channels of the caves are developed in first direction, in second and third direction just some parts of main passages are developed. Hydrology In the studied area there is a confluence of two underground rivers. First river is Gan He river the second one the river from Swal- low cave. To the Natural Bridge water Gan He flows on the surface in the direction NW-SE, after flows bellow bridge sinks to the ponor of Gan He cave, where reaches the water from Swallow cave which flows also through Middle cave and then to Gan He cave. At low water rivers join under- ground and flow towards spring which should be out of the area, probably in the main river valley. Only at high waters riv- ers fill the lower cave galleries and flow on the surface for two times and then flow trough the River cave into the main river. At the time of the visit the discharge of both rivers together was about 100 l/s. The temperature of water in Swallow cave was 9,7 0 C and the temperature of air was 10,4 0 C. F. Gabrovek, A. Mihevc, B. OtoniŁar, N. Zupan Hajna Speleological Exploration at Tianshengqiao ... Fig.2.4.3. Dark-grey platy internaly laminated Lower Triassic marly limestone. The rock is to characteristically bioturbated and shows mottled structure. Long axis of the figure: 1 m. (Photo: B. OtoniŁar) kitkras2.p65 3.12.98,8:56 163 Black 164 2 F. Gabrovek, A. Mihevc, B. OtoniŁar, N. Zupan Hajna Speleological Exploration at Tianshengqiao ... Fig.2.4.4. Dip of strata and strikes of structural zones, intensity is expressed by length of the bars. Fig.2.4.5. Tianshengqiao natural bridge area, caves and generalised geological structures of the area. kitkras2.p65 3.12.98,8:56 164 Black 165 2 F. Gabrovek, A. Mihevc, B. OtoniŁar, N. Zupan Hajna Speleological Exploration at Tianshengqiao ... Caves In the area of Natural Bridge we visited seven caves but because of the lack of time and equipment we were able to surveyed only three of them. 1. Swallow cave: South of the bridge bel- low the 90 m high wall there is an opening to the 50 m high and 70 m wide entrance into Swallow cave. In this part of the cave here are the remains of human dwelling and traces of saltpetre production from the cave sediments. Cave was researched and surveyed up- stream for about 500 m, total length of the surveyed part of the cave is 938 m. In the cave two morphological and genetic units can be seen an active narrow, high gallery and a maze of older, phreatic channels. Active narrow and high gallery which rise in surveyed part for 21 m. Trough this gallery flows river which carries drift wood, among which 40 cm thick and several m long trunks were found, showing, that this river is a sinking river. The discharge of the river was about 50 l/s. Survey was done upstream until a lake and 3 m high cascade. The canyon is few m wide and about 20 m high, becoming lower upwards. The main channel is developed along strong structural zone with faults and fis- sures in E-W direction and in some parts in fissures which form the angle of 45 0 with it, this is NE-SW direction. The wall rocks consist of thin bedded to platy dark grey in some places obviously bioturbated lime- stone and marly limestone with dissolution seems and stylolites. Smaller and up to ten cm large scallops are the most prominent features of the cave rocky relief. Other morphologic unit of the cave is a maze of older, phreatic channels which are about 15 m above the actual stream in the entrance part. The galleries are dipping with strata and they used one bedding- plane for formation. The orientation of these channels is related to two different Fig. 2.4.6. Entrance to Swallow cave on the left and Tianshengqiao natural bridge on the right. (Photo: A. Mihevc) kitkras2.p65 3.12.98,8:56 165 Black 166 2 F. Gabrovek, A. Mihevc, B. OtoniŁar, N. Zupan Hajna Speleological Exploration at Tianshengqiao ... structural zones, the most important is E-W direction and the second one is NE-SW di- rection. At the entrance part of the cave smaller anastomoses channels are visible along three several metres separated bed- ding plan partings. Sediments, gravel, sand and silt were found in upper parts of the cave, indicat- ing older infill of the cave. From the small phreatic channel at the top of high gallery sample of sand mixed by silt was taken. It was analysed by x-ray on the Institute of Mineralogy, University of Ljubljana by the Phillips diffractiometre with Cu K a (l = 1,54 x 10 1- nm) and automatic divergence slit. The analyse was shown the following min- eral composition: quartz, feldspar, chlorite, dolomite, muscovite, calcite, augite and salt- petre (KNO 3 ). Quartz, chlorite, muscovite, feldspar and augite were brought into the cave by the stream from noncarbonate rocks. Dolomite and calcite are originated from cave walls. 2. Middle cave: River from the Swallow cave sinks after 50 m of flow on the sur- face in a cave, which has another entrances further E. We could follow the river in the cave towards east where it probably joins the Ganhe cave. In the depression where the second en- trance to the cave is there is also small can- yon, which was dry in the time of the visit. Cave all the time follows the E-W direction, the second entrance is opened along the fissures in N-S direction. 3. Ganhe cave: Gan river flows under the Tianshengqiao and after 200 m sinks in a cave. Entrance to the cave is narrow and Fig.2.4.7. Our exploration ends at small pool which leads to the step with waterfall. The proof that passage continues and that river in the cave is a sinking river is choked drift wood. (Photo: B. OtoniŁar) Fig.2.4.8. Main narrow gorge-like passage of the Swallow cave. (Photo: B. OtoniŁar) kitkras2.p65 3.12.98,8:56 166 Black 167 2 F. Gabrovek, A. Mihevc, B. OtoniŁar, N. Zupan Hajna Speleological Exploration at Tianshengqiao ... Fig.2.4.9. In some places narrow main passage of the Swallow cave becomes much wider. (Photo: B. OtoniŁar) Fig. 2.4.10. Plan and profile of the Swallow cave. steep. From this cave water flows in at least two directions as mentioned above. 4. Tunnel cave: This is 81 m long cave. Its entrance is in the vertical wall of the can- yon above its bottom. Cave rises towards east at first, than lowers and opens under the vertical wall again. Cave is a remaining of an old, because of the outside influences much transformed phreatic gallery. In gen- kitkras2.p65 3.12.98,8:56 167 Black 168 2 F. Gabrovek, A. Mihevc, B. OtoniŁar, N. Zupan Hajna Speleological Exploration at Tianshengqiao ... eral cave is also elongated in E-W direction, but in the cave is well expressed also NE- SW direction. 5. Muddy cave: Its entrance is in the low- est part of the second biggest depression in the area. It is temporary spring of the river which flows on the surface for about 200 m and then sinks into the Dry river cave. At the time of the visit it was dry, ex- plored only to the level of the lake of hang- ing water. Cave follows the dip of bedding plane which is 170/20,25. 6. Dry river cave: Cave is a ponor of the river coming from the Muddy cave. Cave is on the opposite, eastern side of the depres- sion. Cave gallery starts with 20 m high entrance and can be followed for 335 m to the exit at the riverbed of the main river. Most part of the cave is more than 10 m wide and high, and dips evenly for 27 m. Two collapse entrances reach cave in the E part, very near the spring from the cave in the main valley of the area. At the time of the visit cave was dry, some water was in the pools of trapped water only. At rainy season cave transmits large water quantity. Galleries are oriented along structural zones in E-W direction, some parts of the Fig. 2.4.11. W Entrance to the Middle cave. (Photo: A. Mihevc) Fig. 2.4.12. Plan and profile of the Tunnel cave. kitkras2.p65 3.12.98,8:57 168 Black 169 2 F. Gabrovek, A. Mihevc, B. OtoniŁar, N. Zupan Hajna Speleological Exploration at Tianshengqiao ... channels also use well expressed N-S direc- tion and NE-SW direction. The collapse en- trances are connected to crossing of main Fig. 2.4.13. Entrance to the Dry river cave is opening at the end of large collapse depres- sion. (Photo: A. Mihevc) Fig. 2.4.14. Plan and profile of the Dry river cave. structural zones, where the limestone is more broken. Conclusions Natural bridge Tianshengqiao and closed depressions between Swallow cave and the River cave have developed in the limestone sequence which is pure in upper part and more marly in the lower part. Be- cause of the great gradient caused by the downcutting of the main river both Gan He river and the Swallow cave river start to sink in the karst. First galleries probably fol- lowed the bedding planes and followed the dip. Some of the phreatic small cross sec- tion and with old sediments filled galleries can still be seen in the Swallow cave. Open- ing of the karst laterally to the valley of the main river made sinking of the rivers possi- ble. Rivers probably formed narrow and high underground galleries. Collapses elon- gated along the main structures in E-W di- rection occurred. Collapse depressions were latter connected in elongated canyon like depression, with some tunnel caves and the Tianshengqiao bridge as the remains of the previous cave system. The Tianshengqiao cave system pre- sents an interesting case of the speleo- genesis and gives an opportunity for many new cave research and discoveries. kitkras2.p65 3.12.98,8:57 169 Black 170 2 Geomorphology Cave developed in relief of cones and depressions. In this surface valley like de- pressions and smaller closed depressions developed. Peaks of the cones are at 1900 m a.s.l. and the bottoms of depressions at 1700 m a.s.l. There are also larger depres- sions, they are deeper, with bottoms at 1600 m. Entrance to the cave is below the steep slope of a karst cone, which below it con- tinues to the large cockpit. Slopes of cones and the cockpit are inclined to 40. There is some soil in the bottoms of depressions. In larger and deeper depression some sur- face streams appear. These depressions are being flooded too. Geology Lithology The cave and its surroundings lie in Lower Permian crinoide limestone and po- rous grainy dolomite. Where limestone is present, the partly leached stems of crinoids protrude from the weathered cave walls; foraminifers, brachiopods, briozoas, corals and spines of Echinoidea - sea urchins - are also visible. In the passage on the west side of the entrance doline, opposite the main passage and stratigraphically somewhat below the level observed in the main passage, a nearly black micritic limestone appears. Similar sediments can be observed above the cave, where limestone gradually 2.5. KARSTOLOGICAL RESEARCH OF THE CAVE BY XINGCHANG VILLAGE Franci Gabrovek, Andrej Mihevc, Bojan OtoniŁar, Nadja Zupan Hajna prevails over dolomite. In this part we ob- served only small irregular lenses of coarse- grained dolomite. Directly above the cave, in dark micritic limestone, we found inter- esting thin laminas and ripples of crinoids and foraminifers (Fig. 2.5.1.). Limestones are of the packstone and wackestone type and are recrystallised in places. Among the allochems, bioclasts and peloids - mainly micritized bioclasts - prevail. The most fre- quent fossils are echinoderms, primarily crinoids, and fusulinid foraminifers, dasy- cladacean algae fragments, individual corals, gastropods and briozoas, while fragments of various indefinable tests also appear. The matrix is mostly micrite, which can be washed, recrystallised or selectively dolomitized. Drusy mosaic spar may be present in places. Among structures, we observed the pre- viously mentioned laminae of individual bioclasts in micrite. Allochems are fre- quently oriented with their longer axis par- allel to the stratification. In places, distinct bimodality is noticeable in the samples. Rarely grains of framboidal pyrite are pre- sented. The structure of the dolomite is euhe- dral to subhedral (Fig. 2.5.2.), the grains in- dicate a zone distribution of impurities. In some places in dolomite, there are remains of micrite and undolomitized crinoidal plates (selective dolomitization) (Fig. 2.5.2.). Somewhat higher above the cave, stylo- litized limestone with nodules and lenses of black chert (Fig. 2.5.3.) appear. Fossil re- mains are well preserved here, especially crinoids and fusulinids. F. Gabrovek, A. Mihevc, B. OtoniŁar, N. Zupan Hajna Karstological Research of the Cave by Xingchang ... kitkras2.p65 3.12.98,9:09 170 Black 171 2 F. Gabrovek, A. Mihevc, B. OtoniŁar, N. Zupan Hajna Karstological Research of the Cave by Xingchang ... Figure 2.5.1: Various bioclasts redeposited in micrite; among them we observe fusulinid foraminifers, crinoidal plates, various indefinable tests and rare brachiopod spicules. Lower Permian limestone directly above the cave. Long axis of the figure: 1,25 cm. (Photo: B. OtoniŁar) Figure 2.5.2: Coarse grainy dolomite in which most of the cave has developed. The grains are chiefly subhedral with well seen zonation. The large grains represent non-dolomitized crinoidal plates selective dolomitization. Lower Permian. Long axis of the figure: 1 cm. (Photo: B. OtoniŁar) kitkras2.p65 3.12.98,9:09 171 Black 172 2 Rock similar to that described above can also be found in the caves broader sur- roundings. The limestones described above were deposited in the middle and outer shelf. F. Gabrovek, A. Mihevc, B. OtoniŁar, N. Zupan Hajna Karstological Research of the Cave by Xingchang ... Primarily limestones of the packstone type with more or less rounded grains oriented parallel to the stratification represent rather higher energy shallow water banks or shoals. Limestones of the packstone type Figure 2.5.3: Bedded stylolitized fusulinid-crinoidal black limestones with nodules of black chert. Lower Permian broader vicinity of the cave the beds are stratigraphically above the cave. (Photo: B. OtoniŁar) Fig.2.5.4. Dip of beds and strike of tectonic structures, intensity is expressed by length of the bars. kitkras2.p65 3.12.98,9:09 172 Black 173 2 F. Gabrovek, A. Mihevc, B. OtoniŁar, N. Zupan Hajna Karstological Research of the Cave by Xingchang ... with distinct macrofossils are probably sediments of the marginal parts of patch reefs or beds flanking the bulid-ups. Micritic limestone with bioclastic laminae and rip- ples was deposited in shallow water marine conditions with open circulation close to the wave-base. Periodically during higher energy events fossils were redeposited into this sediment. Limestones with chert were probably deposited in somewhat deeper water in the surroundings of build-ups on the shelf slope. Structural elements Carbonate beds generally dip toward SE. Entrance part and the end part of the cave generally follow the dip of strata 140/20- 35. The middle part of the cave follows the strong vertical fissured zone E-W. NE - SW and N - S directions of tectonic structures are also expressed (Fig. 2.5.4.). Clastic sediments Sediment samples were taken for fur- ther mineralogical analyses, two on the slope above village Xingchang and one in the cave. Yellow loam from middle part of the cave contains predominantly quartz, some montmorillonite, muscovite and chlorite, kaolinite and goethite are present in traces. Fig. 2.5.5. Streching profile and ground plan of the cave by Xingchang village. kitkras2.p65 3.12.98,9:09 173 Black 174 2 F. Gabrovek, A. Mihevc, B. OtoniŁar, N. Zupan Hajna Karstological Research of the Cave by Xingchang ... Accumulation of yellow weathered loam on slope above village was mixed with some chert pebbles comprises mostly quartz, and very small amount of montmorillonite, mus- covite, chlorite and kaolinite. Yellow loam on the slope above road which was under construction that time consists mostly of quartz, and little of montmorillonite, muscovite, gibbsite, chlorite and kaolinite. Regarding on mineral composition yellow loam on the surface and in the cave have had the same origin. They probably originated from weathered rests of lime- stones rich with chert nodules (Fig. 2.5.3.). Cave Geographical position: The entrance of the cave lies in a smaller collapse doline which is located on 1720 metre above sea level, NW from the Xingchang village, on slope above karst polje. Basic data about the cave: Length: 541m Depth: 99m (between highest and low- est points of the cave) Horizontal length: 510m Stretching in E-W direction: 330m Stretching in N-S direction: 90m Description of the cave: On the bottom of the collapse doline with diameter of 20 m are two entrances, one of the eastern longer passage and the other of the shorter western passage (Fig. 2.5.5.). Eastern passage: The narrow and low entrance in the east- ern passage becomes after few metres widely opened and follows the bedding plane parting dip under the inclination of 20 0 . In this part numerous fossils (especially crinoid stems) jut out of the weathered cave walls. At the beginning ceiling is lower than 1m, but highness of the passage monoto- nously increases and after 100m passes into largest hall in the cave (50X40X20m). On the bottom of the hall is an entrance that leads into series of short vertical steps that end (continue) with narrow muddy chan- nel (unmeasured) 30m below the hall. Channel is already bellow the level of the flooding waters. The hall is on the eastern side break off with flowstone barrier. Up to 10m high and up to 25m wide passage is covered with flowstone and proceeds towards NW from the hall. After 100m channel turns towards SE and continues with flowstone slope. At the bottom of the slope is the most remote and the deepest measured point of the cave. The final parts of the cave are beautifully decorated by numerous and various forms of flowstone. Western passage: Western passage is developed along ver- tical E-W oriented fissured zone. Ten metre high entrance is triangular in shape and the walls diverge into fissure on the roof. The passage steeply descend toward W under the inclination of 35 0 . The bottom is cov- ered by gravels and the walls are bare. Fig.2.5.6. The stalagmite in the western passage of the cave by Xingchang village. kitkras2.p65 3.12.98,9:10 174 Black 175 2 Introduction We investigated lithological properties of carbonate rocks of the Yezong plateau, which is typical conical karst area, and of the northern bank of the Beipanjiang river, that cut into the plateau. 2.6. LITHOLOGIC CHARACTERISTICS OF YEZHONG PLATEAU Bojan OtoniŁar The oldest rocks included in the re- search were Upper Carboniferous lime- stones wich were subsequently karstified and covered by lower coal series, which we will not treat lithologically here. These rocks were followed by Lower Permian mixed carbonates and siliciclastic beds Bojan OtoniŁar Lithologic Characteristics of Yezhong Plateau Fig.2.6.1. Lithostratigraphic sketch of Beipanjiang river canyon and Yezong plateau kitkras2.p65 3.12.98,9:10 175 Black 176 2 which pass into Lower Permian limestone (Figs. 2.6.1., 2.2.3., 2.2.6.). Over the another paleokarst surface upper coal series and basalts occur in the topmost part of the pro- file and are also not a part of lithologic re- search. The total thickness of the rock in- cluded in the research of the Yezhong pla- teau area is about 1000 m. We assessed the main lithologic types of rock in the field, and took samples for microscopic research of the most characteristic ones. Rock research in the main profile was combined with field observations and in- formational sampling in some other ar- eas. In other locations in the broader vi- cinity of the Yezhong plateau we also ex- amined Upper Carboniferous oncolite limestones, Lower Permian transitional strata and Lower Permian limestones and dolomites. Profile from the top of the Beipanjiang river canyon and the road above the reserve menagement (Fig.2.8.3.) In the lower part of the Upper Carbon- iferous part of the profile, thick bedded light gray primarily sparry limestones with small onciods, peloids, bioclasts and intra- clasts prevail in which the quantity of basic components varies. We can observe the al- ternation of some similar basic lithofacies among which laminated biointraoncos- parite limestones, biosparite-fusulinid lime- stones, and biosparite limestones with large corals (height: up to 10 cm; diameter: 2 cm), foraminifers, and crinoids, prevail. Limestones are often laminated, and contain laminae and ripples primarily of small oncoids and partly rounded fossil de- Bojan OtoniŁar Lithologic Characteristics of Yezhong Plateau Figure 2.6.2: Poorly sorted bioclastic grainstone. Bioclasts of various origins (algal plates, foraminifers, etc.) are more or less micritized, partly rounded and poorly sorted. The origin of large allochems is not entirely clear, although they do point to micritized and otherwise modified bioclasts (fusulinid foraminifers are noticeable). The outer shelf high energy sand bars. Upper Carboniferous. Long axis of the figure: 1 cm. (Photo: B. OtoniŁar) kitkras2.p65 3.12.98,9:10 176 Black 177 2 bris, especially crinoids. A bimodal distri- bution of clasts is also characteristic. Fusulinid foraminifers, plates of crino- ids, bivalve tests and algal debris are fre- quent among fossils. Gastropods and, in some beds, solitary corals up to 2 cm in di- ameter, occur sporadically. In some thin sections, we observed Tubiphytes. Charac- teristic micritisation (Fig. 2.6.2.) and coating of bioclasts can be observed under a micro- scope as well. Sometimes it is difficult to dif- ferentiate clusters of micrite from the ma- trix and from various irregular micrite coats. In microscopically examined samples mainly drusy mosaic spar occurs, while isopachous fringing A cement occurs less often. Crinoidal plates are surrounded by syntaxial rim cement. The lower part of the Upper Carbonif- erous part of the profile is divided from the upper by belt of dark limestones with foraminifers, crinoidal plates and individual corals. The limestones are of the packstone type. Bioclasts prevail among the allochems, but oncoids of the algal ball type and peloids are present as well. Among bioclasts, foraminifers, primarily fusulinids (Fig. 2.6.3.), crinoidal plates, algae, individual gastropods and fragments of various tests and corals are present. Bioclasts are fre- quently micritized and coated (Fig. 2.6.3.). The micritic matrix is frequently imper- ceptible due to the dense packing of parti- cles. In some places it is partially washed, recrystallised or dolomitized. Crinoidal plates may be surrounded by syntaxial rim cement. In some microscopically examined samples, we observed pyrite and tiny cal- cite veins. In the belt of dark limestones, thinner lenses of breccia, up to approximately 0.5 m thick, with stylolitic seams occur also. Among other things, we find clasts of colo- nial corals in it. In the thin sections (Fig. 2.6.3.) directly beneath the breccia, the matrix is repre- sented by a brown secondary pedogenic micrite with a clotted, indistinct aveolar- septal and in some places a laminated fab- ric; rhizolites (Fig. 2.6.4.) and brown pellets also occur. The described features are char- acteristic of beta calcretes (Tucker & Wright, 1990). In the host rock micritized fusulinids and peloids prevail (Fig. 2.6.3.). Some stalactitic vadose cement can be ob- served on the lower sides of the clasts, or on the ceilings of the infilled voids in the host rock (Fig. 2.6.3.). Lighter sparry limestones with forami- nifers in which, in some places, colonial cor- als and individual gastropods and crinoids are found, succeed the beds of dark lime- stone. The limestone is micritic in some places. This limestones are succeeded by micri- tic and then by sparry limestone of the grainstone type with small oncoids and Bojan OtoniŁar Lithologic Characteristics of Yezhong Plateau Figure 2.6.3: Pedogenically altered fusulinid crinoidal limestone. We observed secondary brownish micrite (calcrete) in which an alveolar-septal fabric is noticeable. In the lower parts of the bedrock remains we also observe stalactitic vadose cement. Upper Carboniferous. Long axis of the figure: 1,25 cm. (Photo: B. OtoniŁar) kitkras2.p65 3.12.98,9:10 177 Black 178 2 limestones with rounded bioclasts and oncoids of the algal ball type. We can ob- serve two generations of sparite cement in the thin sections; an A generation of fring- ing calcite and drusy mosaic spar. In some places the limestones are graded and have a bimodal distribution of allochems (Fig. 2.6.5.). Larger allochems, up to a few centimeters in size, have micritized margins and in some places could be coated. Higher up, grainy limestones, that is densely packed biomicrite of the pack- stone type (Fig. 2.6.6.) occur. Fusulinid foraminifers and crinoidal plates prevail among the fossils. The matrix is difficult to determine, only around the crinoidal plates is there a clearly defined syntaxial rim cement. Limestones of the grainstone type ap- pear in this part of the profile (Fig. 2.6.7.) as well. In them micritized bioclasts, differ- ent peloids, primarily irregular in shape, up to 0.5 cm irregular clots of micrite and/or oncoids of the algal ball type and grape- stone, predominate. The main component among fossils is represented by micritized and coated fusulinid foraminifers but crinoidal plates and gastropods also appear. Most peloids were probably formed by micritization and coating of bioclasts and grapestones since, in the majority of them, a poorly preserved inner texture is still vis- ible. Some forms of the micritic clots are similar to Tubiphytes. All allochems are more or less well-rounded. Here the allo- chems are also surrounded by isopachous fringing A cement, while all of the remain- ing interparticle pores are filled with drusy mosaic spar. A few meters bellow the coal series is a distinct bed with irregular concentric, up to 5 cm large, oncoids (Fig. 2.6.8.). Very dis- tinct ones are also to be found on the oppo- site side of the canyon, at an aerial line dis- tance from the described profile of about 10 km. Large oncoids, probably belonging to the same horizon, were also found by the bridge across the Beipanjiang river. We microscopically examined two samples from this area, of which clotted micrite and micritization and coating of allochems, es- Bojan OtoniŁar Lithologic Characteristics of Yezhong Plateau Figure 2.6.4: Lower part of the same thin section as in figure 2.6.3. Rhizolites, indicating pedogenic alteration of the bedrock and/or sediment. Upper Carboniferous. Long axis of the figure: 0,75 cm. (Photo: B. OtoniŁar) kitkras2.p65 3.12.98,9:10 178 Black 179 2 pecially bioclasts, is characteristic (Fig. 2.6.9.). Fusulinids are most common among fossils, but green algae and individual gas- tropods also appear. Among oncoids (Fig. 2.6.9.), ones with an inner spongy fabric and an indistinctly laminated denser micritic coat and oncoids of the algal ball type pre- vail. The described limestones are succeeded by a lower coal series, where thinner beds of coal, which are sometimes exploited in small mines in which only a few miners are employed, appear between mudstones and sandstones. The lower contact between Upper Carboniferous limestones and Lower Permian clastics is expressed by paleokarst which we did not observe in the field as it was covered by slope gravel. Transition beds succeed the coal series (Fig. 2.6.10.) which we studied closely some 10 kilome- ters south-west of the described profile. In these beds black limestones alternate with mudstones, marlstones, and sandstones (Fig. 2.6.10.). Transition beds are succeeded by lighter Lower Permian limestones with crinoids, foraminifers, corals, gastropods, brachiopods and individual patches of co- Bojan OtoniŁar Lithologic Characteristics of Yezhong Plateau Figure 2.6.5: Poorly laminated and graded bioclastic - intraclastic limestone. Upper Carboniferous. Long axis of the figure: 30 cm. (Photo: B. OtoniŁar) Figure 2.6.6: Fusulinid crinoide packstone. Syntaxial rim cement is visible around the crinoidal plates. Upper Carboniferous. Long axis of the figure: 1,25 cm. (Photo: B. OtoniŁar) kitkras2.p65 3.12.98,9:10 179 Black 180 2 lonial corals. Chert also appears in the lower part of the limestones. The microscopically examined black limestone of the transitional beds represents a characteristic organic dark-brown to black laminated densely-packed biomicrite lime- stone of the wackestone type. Fragments of partly deformed tests of bivalves, ostracods, individual gastropods and brachiopods, and individual crinoidal plates appear. The tests are oriented parallel to the stratification, which emphasizes the lami- nated structure. Black organic matter and pyrite are present in the micritic matrix. Zhongzhai In the vicinity of the Zhongzhai karst val- ley (Fig. 2.8.3., 2.8.9.), stratigraphically somewhat above the transition beds, bed- ded and frequently laminated light gray crinoide limestones and darker micritic limestones, in which gastropods and ostra- cods can be seen in some places, alternate. Leached crinoids are also visible in some cavern walls. In general these limestones are some- what more micritic than the previously de- scribed Upper Carboniferous limestones. Biomicrite and/or pelbiosparite (washed and/or recrystallised) are mostly of the wackestone and packstone type. Bioclasts and peloids prevail among allochems. Ornamented faecal pellets occur in limestones where there is noticeable bioturbation. Bioclasts are more or less micritized, probably a large part of the peloids formed with complete micritization of bioclasts (Fig. 2.6.11.). We observed in- distinct coatings around some allochems. The allochems are fractured and broken in some samples. Among the fossils, fusulinid forami- nifers, crinoidal plates, briozoas, ostracods, various micritized bioclasts and fragments of various indefinable tests, are present. Bojan OtoniŁar Lithologic Characteristics of Yezhong Plateau Figure 2.6.7: Weel sorted bioclastic peloidal grainstone. Bioclasts (fusulinids, gastropods, and individual crinoidal plates) are partly rounded, micritized, and some are even coated. Allochems cemented into clots grapestones and oncoids of the algal ball type also appear. High energy shoals of the outer shelf. Upper Carboniferous. Long axis of the figure: 1,25 cm. (Photo: B. OtoniŁar) kitkras2.p65 3.12.98,9:10 180 Black 181 2 Bojan OtoniŁar Lithologic Characteristics of Yezhong Plateau Figure 2.6.8: Bed with undulate laminated macrooncoids of over 5 cm in diameter. Upper part of Upper Carboniferous limestones. Long axis of the figure: 70 cm. (Photo: B. OtoniŁar) Figure 2.6.9: Peloidal oncolite packstone/grainstone. Irregular peloids of various size, micrite and fossil clots, and various micritic oncoids and chips of the above-mentioned allochems pass into each other and are difficult to define accurately. Larger oncoids with spongy inner fabric and denser, poorly laminated coat are the most distinctive. The bimodal allochem distribution is characteristic. Upper Carboniferous. Long axis of the figure: 1,25 cm. (Photo: B. OtoniŁar) kitkras2.p65 3.12.98,9:12 181 Black 182 2 Bojan OtoniŁar Lithologic Characteristics of Yezhong Plateau The microscopically examined samples are inhomogeneous due to bioturbation, only in some places can an indistinct lami- nation be observed. In one sample fine grains of framboidal pyrite, filling some of the chambers of fusulinid foraminifers (Fig.2.6.11.). The samples examined under a microscope were dark brown to black as well. As mentioned, the matrix is mainly micrite, although clotted micrite may ap- pear. Syntaxial rim cement appears around crinoidal plates. In some places patches of more or less impure drusy mosaic calcite and microspar are seen. Majiachong (Fig. 2.8.3) Stratigraphically higher, more or less in the same area and relatively close to the contact of limestones and the second coal series and basalts, on more or less micritic dark limestones with thick calcite veins, lie lighter crinoide limestones which pass into black limestone with chert in the upper part of the observed profile. The lower bituminous limestones are es- sentially biomicrites of the wackestone type (Fig.2.6.12.). They contain fragments of vari- ous tests (bivalves, ostracods, algae, briozoas, gastropods) and individual crinoidal plates. Among the others allochems we also ob- served tiny medium to well-rounded dark peloids in thin sections. Black stylolitic seams are also characteristic (Fig.2.6.12.). Crinoide limestones higher in the pro- file are mainly very densely packed pelbio- sparite/micrite of the packstone type (fig.2.6.13.). Partly micritized crinoids and foraminifers dominate among fossils. Indi- vidual algae also occur (Dasycladaceae). Among other grains, peloids are frequent, oncoids of the algal ball type and intraclasts also appear. Crinoidal plates are in some places surrounded by syntaxial rim cement. Contacts between the described lime- stones and upper coal series and/or basalts Figure 2.6.10: Mixed siliciclastic-carbonate transition beds between lower coal series and Lower Permian limestones. Long axis of the figure: 4 m. (Photo: B. OtoniŁar) kitkras2.p65 3.12.98,9:12 182 Black 183 2 Bojan OtoniŁar Lithologic Characteristics of Yezhong Plateau are paleokarstic, although paleokarst forms could not be observed in the field due to the fact that they are covered by the weath- ering product of sandstones and basalts. Flowstone, seen on the surface in the up- per profile, may be consistent with this paleokarstic phenomena. Taishaba Some ten kilometers towards the NE from the Yezhong plateau, and strati- graphically probably somewhere in the middle between the upper and lower coal series and/or basalts, we geologically sur- veyed the terrain around the village of Taishaba (Fig. 2.2.9.). We took some infor- mational samples for microscopic analysis. Thick-bedded limestones are of a simi- lar appearance in a whole area and are me- dium to dark gray, more or less micritic and contain crinoids. Brecciacalcrudite, fol- lowed by black limestones with chert, is of Figure 2.6.11: Peloidal bioclastic grainstone. Peloids are mostly irregular and poligenetic (micritized fossils, various micrite clots, faecal pellets, etc). Among bioclasts, various foraminifers appear, among these fusulinids, crinoidal plates and individual indefinable tests, are the most distinctive. Lower Permian. Long axis of the figure: 0,75 cm. (Photo: B. OtoniŁar) interest in the lower part. Above these lime- stones, lighter micritic limestones with al- gae and individual laminated crinoids, in- dividual patches of colonial corals (up to 10 cm in diameter), gastropods, ribbed fine bivalve tests and foraminifers appear. The limestones lying over the cherts have a mot- tled appearance due to selective dolomiti- zation. Microscopically, the samples are of the wackestone or packstone type. Because the matrix is partially washed or recrystallised, it is often difficult to distinguish micrite from micritized grains. In some places we observed clotted micrite. Among the allochems, we observed peloids of different origin (angular, partly- rounded recrystallised grains, micritized bioclasts, small oncoids of the algal ball type, various clots of micrite, and pellets, intra- clasts (partly recrystallised biomicrite) and faecal pellets. Among fossils, foraminifers, crinoidal plates, various indefinable thin tests and in- kitkras2.p65 3.12.98,9:12 183 Black 184 2 Bojan OtoniŁar Lithologic Characteristics of Yezhong Plateau dividual algae, appear in thin sections. Bioclasts are coated in some places. Crinoidal plates are frequently sur- rounded by impure syntaxial rim cement. Under a microscope, in some parts of the thin sections, the selective dolomitization of micrite is visible. In such cases we ob- served euhedral to subhedral dolomite crys- tals which have impurities distributed in- side in zones. Conclusion Despite the limited research time, we can, based on field data and microscopic analyses of informational samples, draw some of conclusions. We recognized the high variegation of rocks, in terms of lithology and microfacies, and also in terms of depositional environ- ments and diagenesis. Carbonates are rep- resented primarily by limestones, which are sometimes substituted by coarse, grainy dolomite. In Lower Permian limestones, nodules and lenses of the chert also appear. Generally speaking, Lower Permian lime- stones are similar to Upper Carboniferous limestones, although the former have more micritic limestones, deposited in somewhat less agitated depositional environments. In the somewhat higher energy outer parts of shallow shelf seas, primarily pure thick bedded limestones of the grainstone and packstone type were deposited. Bio- clastic limestones were deposited on open shelves, on banks or on shoals, which sepa- rated the calmer parts of the middle shelf from the outer somewhat deeper areas of the slope, and in the vicinity of build-ups or small patch reefs. Although we did not notice build-ups or mounds morphologi- cally in the field, some facies, which are characteristic of their cover and flanking Figure 2.6.12: Bioclastic wackestone/packstone. Among allochems larger and smaller debris of various fossils (gastropods, algal plates, etc), rarely peloids are presented. Due to the fine frac- tion of the grains, it is difficult to recognize the matrix, as it is probably a fine fraction of debris of various allochems. The sample is cut by a marked stylolitic seam. Lower Permian. Long axis of the figure: 1 cm. (Photo: B. OtoniŁar) kitkras2.p65 3.12.98,9:12 184 Black 185 2 Bojan OtoniŁar Lithologic Characteristics of Yezhong Plateau beds (biogenetic grainstone and pack- stone), indicate them. Crinoids, briozoas, Tubiphytes, and also algae and corals, thrived in outer, higher energy shelf envi- ronments. These organisms could also build up to form banks, small reefs of various forms and composition and patch reefs, from which they were periodically redepo- sited into the rather calmer environments. There different organisms micritized bioclasts, coated them and adhered them and their debris into different clots with car- bonate cement. Bioclastic sedimentation was particu- larly aboundant in the area of normal wave activity. Under these conditions, limestones of the grainstone type with rounded bioclasts were deposited. They represent the layers which have been deposited on the highest parts of the shelf margin. The more rarely present micritic lime- stones were deposited in calmer areas in the vicinity of the build-ups, behind the barri- ers or somewhat deeper on shelf slopes. Some darker limestones of the packstone and wackestone type were probably depos- ited in bars and shoals of the middle shelf behind the main barriers (shallow lagoons and bays). Bioturbation and in situ produc- tion of carbonate grains is characteristic of these conditions. Oncolite limestones with macrooncoids in the upper part of the Upper Carbonifer- ous were deposited in very shallow water with a rather limited circulation, although not so much as to prevent grains from turn- ing over in conditions of slow sedimenta- tion of carbonate mud (possibly under tidal influences). Similar sediments can be found in tidal channels, where they formed under the influence of the tidal currents. A shorter subaeraily exposure of the carbonates, ap- proximately in the middle of the Upper Carboniferous part of the profile, is indi- cated by pedogenically altered limestones with rhizolites, alveolar-septal fabric and stalactitic vadose cement. In this part we noticed dolomite only beneath pedogeni- Figure 2.6.13: Crinoidal packstone. Allochems (bioclasts and peloids) are densely packed. Among bioclasts besides crinoids different foraminifers and Dasycladaceae appear. Lower Permian. Long axis of the figure: 1,25 cm. (Photo: B. OtoniŁar) kitkras2.p65 3.12.98,9:12 185 Black 186 2 cally altered limestones and this possibly represents dolomitization in the zone where freshwater and seawater mixed. Individual varieties of carbonate do not have a visible effect on morphological forms of large dimensions. They have a greater ef- fect on small morphological forms, which is especially discernible in dolomite areas and areas where mixed carbonate-siliciclastic beds outcrop. The strongest effect on mor- phology in the research area have clastic Bojan OtoniŁar Lithologic Characteristics of Yezhong Plateau rocks of the coal series which, in the other- wise steep slopes of the Beipanjiang river canyon, constitute structural terrace a few hundred meters wide. The bottoms of some hanging karst valleys are also composed of the rock mentioned. The soil cover on this rock is usually very thick. Chert in lime- stone also has an effect on soil cover devel- opment and also indirectly on karst proc- esses. The same is true of mixed carbonate- siliciclastic bed areas. kitkras2.p65 3.12.98,9:12 186 Black 187 2 Some geomorphologic observations of the cone karst relief in West Guizhou are described. The cone examples are taken from old surfaces of high plateaux at an al- titude of over 2000 m, from parts of the re- lief which have gone through rejuvenation due to rivers sunken into canyons or karst plains. The morphology of singular cones and their connecting into relief units with in- tervening depressions are described. The relief develops entirely as karst, with under- ground drainage, and the depressions sink 2.7. SOME GEOMORPHOLOGIC OBSERVATIONS OF THE CONE KARST RELIEF IN WEST GUIZHOU Andrej Mihevc most rapidly, while the cones remain as more resistant rock in between. Cones are visually dominant in the land- scape, although the fastest dissolution proc- esses are of the rock in the depressions. Their growth therefore determines the distribution of the cones, while their form is determined by karstic denudation and slope processes. Cone distribution, slope inclinations, the dis- tribution and form of lapiaz and structural lines thus only indirectly characterise the most in- tensive and dominant processes which take place at the bottom of the depressions. Andrej Mihevc Some Geomorphologic Observations ... Fig. 2.7.1. Karst cones, fenglings at Bajizhai (Photo A. Mihevc). kitkras2.p65 3.12.98,9:12 187 Black 188 2 Cone karst characteristics Karst relief spreads across a large part of southern Chinese territory. We find very different types of relief in this area. Un- doubtedly cone karst with depressions in between is the most characteristic type. Cone karst, irrespective of whether it takes the form of singular cones or towers (fenglin) on a karst flood plain or karst cones with a common base and depression in between (fengcong), aroused the inter- est of researchers some time ago. Cone karst was studied by Chinese and foreign geo- morphologists (Zhang et al. 1987; Zhu Xuewen 1988; Yuan Daoxian 1985; Lin Yushi 1995; HabiŁ 1970, Williams 1985, Ford & Williams 1989). While travelling across the karst in south-west China, we were able to observe the characteristic cone relief in the prov- inces of Guizhou and Yunnan. We were primarily interested in the distribution of cones, their relation to geologic structures and the relation between depressions and morphologically more pronounced cones, which are in essence residual features. Cone karst is especially interesting when com- pared to the Dinaric karst (HabiŁ 1992), where the cone relief is less pronounced and sink-holes are the most pronounced feature among the depression forms. In the field we were able to observe only the basic relief characteristics, rockiness, small forms and cone distribution, due to a lack of time. We chose the most character- istic types of cone karst relief. On a karst plain at the city of Suicheng we observed an isolated cone, a fenglin in the middle of the plain. On the Yezhong plateau we ob- served two different areas with cone relief of the fengcong type, on the highest part of the plateau at the settlement of Maichong and at the edge of the plateau over the Beipanjiang river canyon. Fenglin on the Shuicheng karst polje We chose a small cone with a double peak near the village. The cone stood by it- self at the bottom of the polje, which lies at an altitude of approximately 1860 m. A new road passes the southern slope of the cone, and part of the cone is used as a quarry. We measured the slope inclinations and the cone shape. The approximately 25 m high cone is a corrosion remainder of the cones at the bottom of the polje near the village of Bajizhai. The process of lateral corrosion removed and diminished their density in the middle part, while there are some at the fringes of this large, structurally condi- tioned elongated plain. The cone had a double peak divided by a pass located approximately 8 m lower. The cone slopes are steep, the greatest inclina- tions being 55. The cone slopes have an inclination lower than 30 at their base, while in the central part the inclination ranged between 30 and 40. Lower incli- nations were measured for the cone ridge and the pass between the two peaks. Small relief forms on the cone are mostly lapiaz and rain rills. They indicate that the cone surface was exposed to precipitation water for a long time. A few small, up to 5 m deep vertical shafts were found on the cone ridge. It was not possible to determine whether they are cave shafts or simply cracks widened by corrosion. Since the cone is used as a quarry, work in it exposed up to 1.5 m deep pockets of red-brown soil between two rock blocks. Based on preserved subcutaneous forms on rock blocks we can assume that the soil depth on the pass between the two peaks was lowered between rocks by around 1 m. Farm animals graze on the steep slopes, while on the less steep slopes between the cone peaks corn and some other agricul- tural crops were sown. We were not able to define the amount of soil removal by ob- serving subcutaneous corrosion surfaces. Karst cone depression relief on the Yezhong plateau The Yezhong plateau is a vast levelled surface, dissected into cones and depres- sions lying between them. The relief is lo- cated around 2000 to 2200 m high, the de- Andrej Mihevc Some Geomorphologic Observations ... kitkras2.p65 3.12.98,9:12 188 Black 189 2 pressions are of various depths. The usual karst relief had an amplitude of around 200 m, some structurally conditioned forms, dry valleys, and valleys are up to 300 m deep. The Beipanjiang river cut into the plateau and bared an approximately 2000 m packet of carbonate rock. The bottom of the gorge lies at 700 m. In general, we distinguish three types of karst relief in this area (Fig. 2.8.3.). 1. Beipanjiang river canyon is a typical canyon formed by the rising of the relief in connection with the newest tectonic phase of the development of this territory. The canyon slopes are mostly very steep, in some places the walls of the canyon are completely vertical, and the biggest walls are up to 500 m high. The wall shapes, their inclinations and fall zones depend on lithologic characteristics of the limestone and how broken down they are. The river cut into massive thick bedded Permian lime- stone in which the steep canyon sections are found. In Lower Permian limestone with coal beds and marl the slopes are the steepest, forming a structural terrace up to 2 km wide with an inclination of approxi- mately 20. Massive Carboniferous lime- stone, in which the narrowest and fre- quently vertical part of the canyon formed, lies beneath them. 2. The Yezhong plateau relief formed in Permian limestone and limestone with chert. The plateau is dissected into cone relief with depressions and valleys in be- tween the cones. The surface is 2000 to Andrej Mihevc Some Geomorphologic Observations ... Fig. 2.7.2. Map of distribution of the slope inclinations on the Bajizhai fenglin. kitkras2.p65 3.12.98,9:12 189 Black 190 2 2200 m high. The surface of the cones is rocky, soil is only to be found at the bottom of depressions or on more level slopes be- tween the cones. There are no surface flows in the whole area. 3. Large karst depressions on the plateau formed in areas with exposed Lower Permian coal beds. An indistinct karst re- lief with valleys and plains developed on them. The underground drainage is charac- teristic, a thick soil cover has however re- mained on the surface. The cones devel- oped in the form of residual fenglins in lime- stones which are stratigraphically above the limestones of coal series, for example by the village of Zhongzhai (Fig. 2.8.9.). Karst surface at the village of Majiachong The relief of the plateau at Majiachong village is dissected into cone peaks and in- tervening depressions. The cone surfaces are rocky with belts of soil between the rocks. More soil covers smaller inclinations and depression bottoms. Due to new soil erosion, the exposed cones have traces of subcuta- Andrej Mihevc Some Geomorphologic Observations ... Fig. 2.7.3. Characteristic view of the Beipanjiang river canyon (700 m a.s.l) cut into Yezhong plateau (2200 m a.s.l). There are vertical walls in Permian and Carbon limestones, in less resistant Lower Permian beds with coal series a structural terrace was formed (Photo A. Mihevc). Fig. 2.7.4. View of Yezhong plateau. Cone peaks are approximately 2250 m above sea level (Photo A. Mihevc). kitkras2.p65 3.12.98,9:13 190 Black 191 2 neous erosion, although it is not possible to estimate the amount of erosion, as it differs. This relief is a part of the oldest level- ling of this area. The cone peaks are around 2250 m above sea level, depression bot- toms at around 2000 m. The relative height of the cone peaks is around 200 m (Fig. 2.8.18.). The cone slopes are inclined to 55 and the relief in between, that is moderate val- leys, to 15 - 20. The depressions between the cones are somewhat elongated in the NW SE direction and transversally to this direction. In the lower part of the cone slopes larger inclinations occur in these di- rections, in the upper part the largest incli- nations are distributed around the whole cone. The largest inclinations appear in the middle of the cone slopes. Cones on the canyon edge at Natural Reserve administration centre On the edge of the canyon small cones developed on a morphologically distinct, Andrej Mihevc Some Geomorphologic Observations ... around 2 km wide terrace. They formed in limestone which lay beneath coal series and in which the lower part of the Beipanjiang river canyon also developed (Fig. 2.8.6.). The area of cones is small, with a size of 300 x 300 m. 5 separated cones formed on this relief with a depression in between. The cone surface is rocky, with belts of soil among the rocks. The surface between the cones is covered with a thick layer of weathering product. The soil is eroded due to human impact. Singular blocks are up to 2 m high, signs of breaking off block peaks were found approximately 20 cm below the peaks. Up to 1 cm deep rain rills have developed on the broken surfaces. In some places there are holes several metres deep. The cones are around 100 m above the surrounding relief. The cone peaks are around 1500 m above sea level, and the ter- race edge is roughly 1400 m above sea level. Below the edge the vertical walls up to 500 m high and steep talus cones incline to- wards the river which flows at approxi- mately 750 m above sea level. Fig. 2.7.5. View of cone peaks on Yezhong plateau (Photo A. Mihevc). kitkras2.p65 3.12.98,9:13 191 Black 192 2 Andrej Mihevc Some Geomorphologic Observations ... Fig. 2.7.6. Map of inclinations at the village of Majiachong. Fig. 2.7.7. Cones formed on the terrace in the Beipanjiang canyon (Photo A. Mihevc). kitkras2.p65 3.12.98,9:19 192 Black 193 2 Andrej Mihevc Some Geomorphologic Observations ... Fig. 2.7.8. Cones formed at the edge of Beipanjiang river canyon are influenced only by canyon slope processes (Photo A. Mihevc). Fig. 2.7.9. Model of relief with cone peaks above Beipanjiang river canyon. kitkras2.p65 3.12.98,9:19 193 Black 194 2 Andrej Mihevc Some Geomorphologic Observations ... Fig. 2.7.10. Map of inclinations of cone karst above the canyon. Fig. 2.7.11. Surface at elevation of about 1400 m in Xichou, S Yunnan. Level of the ground water is now deep below the surface and there are only thin soils on the surface (Photo A. Mihevc). kitkras2.p65 3.12.98,9:19 194 Black 195 2 Andrej Mihevc Some Geomorphologic Observations ... The cone slopes incline to 37, the re- lief in between and moderate valleys in- cline to 15 - 20. Larger inclinations appear on the canyon edge and in places where the canyon cuts off parts of cones. The in- clinations in these areas are 60 - 90. The canyon walls cut off parts of cones or de- pressions between them. The canyon, 700 m deep, does not affect the shape of the cones, the effect reaches only to a few me- tres from the edge of the walls. Cone karst on the high elevations differ from the karst features in lower positions, in E Yunnan, Xichou area, for instance. Lower position means different climatic conditions and different relation between water table and karst surface and gradient in karst. There are different stages of develop- ment of the relief in Xichou. Large area was levelled in elevation of about 1400 m. Plain shows it was formed in the water table level where only some about 100 m high fenglin remained. The surface is without any sur- face water and has very thin soil cover. Slopes of the cones are even more stony. On the edge of this surface valley like depressions or karst poljes developed. These youngest features are at elevation at about 1100 m. There are many karst springs and caves at the foot of the slopes in them, but there are also level dry, non active caves in higher levels or the slopes cut caves, that have been filled with alochtonous non- carbonate sediments. Conclusion It is not possible to reach significant morphological conclusions based on a few cone measurements in various karst envi- ronments. Cones are the visually dominant feature in the West Guizhou karst, although the fastest process is rock dissolution in depressions. Their growth and distribution are therefore determined by cone distribu- tion, while their form is determined by Fig. 2.7.12. Leveled surface is a relict of the karst plain that developed in the level of the ground water. Slope transformation of the fenglin cones is very slow, so the sharp transition from the cone to the plain is still visible (Photo A. Mihevc). kitkras2.p65 3.12.98,9:19 195 Black 196 2 Andrej Mihevc Some Geomorphologic Observations ... Fig. 2.7.14. Closed depressions, karst poljes are also formed in elevation of about 1100 m. Several of them are inundated for longer periods during the year (Photo A. Mihevc). Fig. 2.7.13. Valley like elongated depression between cones are result of youngest phase of karst development, their bottoms being at elevation of about 1100 m (Photo A. Mihevc). kitkras2.p65 3.12.98,9:19 196 Black 197 2 karst denudation and slope processes. Cone distribution, slope inclinations, distribution and forms of lapiaz and structural lines thus only indirectly characterise the most inten- sive and dominant processes which take place at the bottom of depressions. Cone relief at the village of Majiachong represents a part of the oldest relief in which the river cut a canyon 1500 m deep. The cones in this area are up to 200 m high, and the cone slopes are very steep. This in- dicates that the depression bottoms are still lowering. Cone relief on the edge of the plateau formed on a structural terrace in the mid- dle of the Beipanjiang river canyon and is much younger, which is probably the rea- son why the cones are only up to 100 m high. Characteristic of this relief is that de- spite its position near the canyon, there are no signs of the canyon determining cone formation. The effect is visible only where mechanical effects of crumbling of the 500 m high walls of the canyon also affect the cones. This insensitivity to the vicinity of the canyon points to vertical drainage, cor- rosion in the subcutaneous karst zone be- ing the most important for cone and other surface features formation. It explains also the absence of surface water flow which would create fluvial forms in the relief. The cone slope inclinations depend to on the relation between lowering of the depressions between the cones and slope processes. The slopes can be grouped into those slopes which are a part of the depres- sion and those which are part of the cone. The depression slopes display a greater de- pendence on structural lines, primarily frac- ture zones, while the slopes of the cones as residual forms show less structure control both in their inclination and direction. Andrej Mihevc Some Geomorphologic Observations ... kitkras2.p65 3.12.98,9:19 197 Black 198 2 Introduction During field research of the cone karst of NW Guizhou I attempted to answer the following question: Does a correlation ex- ist between the distribution of cones and geological structural elements, primarily rock deformation in fault zones. It is known that a series of cone summits adheres to the geological structure (Daoxian, 1991; Song and Liu, 1992; Sweeting, 1992) and that the shape of individual cones depends on the 2.8. EFFECT OF GEOLOGICAL STRUCTURAL ELEMENTS ON GENESIS OF CONE KARST, EXAMPLES FROM NORTHWEST GUIZHOU Nadja Zupan Hajna distribution of geological elements such as, for example, strata dip, fault presence and varying lithology. I have attempted to ex- plain why cones are positioned at their ex- act location and not a few meters away next to the same structure. I did this in the field by measuring of geological elements. A cone is a slope reaching a height from a few meters to a few hundred meters and divided from the others by a depression. In essence a cone is a remnant of rock that is disap- pearing due to karst relief denudation. The Nadja Zupan Hajna Effect of Geological Structural Elements ... Fig. 2.8.1. Work in the stone-pit and road construction cut the cone at Bajiazhai, Liupanshui and expose disintegrated P 1 limestone and dolomite beds. In the stone-pit two karst pocked filled by red soil are opened (Photo. N. Zupan Hajna). kitkras2.p65 3.12.98,9:19 198 Black 199 2 depressions in between are lowered in re- lation to groundwater level and conform to it. The cone or rock remainder can develop and remain at the same location where its summit was protected from weathering by an impermeable cover or more resistant carbonate sequence or in a location where it is limited by more tectonically deformed rock. Tectonic deformations weaken the mechanical hardness of the rock, undermin- ing its structure and thus exposing it to mechanical and also chemical weathering. In this way the rock, which is more me- chanically disintegrated, will in most cases yield to stronger weathering and conse- quently the relief will lower faster in that particular area. Measurements of geological structural elements were carried out on the chosen terrain in the vicinity of the city Liupanshui, in the village of Bajiazhai, then north of the town in the area of the Tianshengqiao natu- ral bridge, east of the town cave near the village of Xingchang, south of the town near the village of Taishaba, near the village of Majiachong and in the karst valley near the village of Zhongzhai on the Yezhong pla- teau, and on the slopes of the Beipanjiang river canyon. The frequency and intensity of the measured structural elements with the length of the data series is presented in the article in the form of charts. Bajiazhai The city of Liupanshui lies in a karst de- pression at 1850 m above sea level and is surrounded by cone summits. There are a number of cone summits at the bottom of the depression so that the city lies between them. In the immediate vicinity of the city, in the small village of Bajiazhai, the con- struction of a road and a smaller excavation have cut off parts of the cone with two peaks leaving its inner structure well ex- posed (Fig. 2.8.1.). The cone is structured of Early Permian limestone, which is quite well dolomitised. In the lower part of the cone, the strata dip towards the south-east 140/10-15, and in the upper part of both peaks towards the Nadja Zupan Hajna Effect of Geological Structural Elements ... Fig. 2.8.2. Dip of beds and strikes of tectonic structures on a cone near the village Bajiazhai near Liupanshui. Intensity is expressed by length of the bars. kitkras2.p65 3.12.98,9:19 199 Black 200 2 north-east 30/30. The layers are heavily frac- tured in different directions, a fissured zone in the direction of 290-110 is most distinct across the second peak, and across the pass between both cone peaks in the direction 310-130. On the northern side, where the cone was cut off for a small stone-pit, planes of faults running in two directions are clearly visible: the first in the direction 290100/90 and the second in the direc- tion 21030/7075. Beipanjiang The Beipanjiang river canyon is cut into the Yezhong karst plateau, which is over 2000 m above sea level. The cones on the plateau are over 2200 m above sea level (Fig. 2.8.3.), the river Beipanjiang flows at 800 m above sea level (Fig. 2.8.4.). Nadja Zupan Hajna Effect of Geological Structural Elements ... Fig. 2.8.3. Yezhong karst plateau with cone karst above the canyon of the Beipanjiang river with the location of significant points marked. We are able to view rock from the mid- dle of the Carboniferous to the late part of the Early Permian. At the bottom of the can- yon there is limestone and dolomite from the middle of the Carboniferous which is light- colored, in thick strata and massive. They are followed by Late Carboniferous limestone in thick strata of the Maiping formation, which are thickly crystalled and very pure. They are followed by paleokarst, and then by the Early Permian Lianshan formation, with flint sand- stone and a coal series containing coal of poor quality. This is followed by Early Permian strata of the Maukou formation which in regard to their age belong to the late part of the Early Permian. Over this lime- stone, main paleokarst developed. Basalt spread over this rock in the Late Permian. The main direction of the fault zones, frac- tures and strata dip in the area of Yezhong plateau are presented in Fig. 2.8.5. kitkras2.p65 3.12.98,9:19 200 Black 201 2 Nadja Zupan Hajna Effect of Geological Structural Elements ... Fig. 2.8.4. The canyon of the Beipanjiang river is cut 1400 m deep into the high plateau Yezhong, the canyon direction in this part is NW-SE (Photo. N. Zupan Hajna). Fig. 2.8.5. Dip of beds and strikes of tectonic structures in the Beipanjiang canyon. Intensity is expressed by length of the bars. kitkras2.p65 3.12.98,9:20 201 Black 202 2 Near the bridge The canyon across the Beipanjiang river follows a NWSE direction, the fissures and parallel faults in the canyon wall run in the same direction. Faults in the NS direction are also visible. To the west the canyon still follows an EW direction, but further on takes a turn at the fault zone in the direc- tion NESW. Faults and fault zones oriented NESW are characteristic of all Chinese neotectonics. The layers in the incline of the canyon dip toward W and NW, with dips 270/20, 310/20, 320/15. Below the monkey reserve administration On the structural terrace, around the middle of the canyon incline, at 1500 m above sea level and immediately at the edge of the river canyon, there are low cone sum- mits (Fig. 2.8.6.). The orientation of the canyon edge here is NWSE, a very strong fissured zone on the structural terrace lies in the direction 310-130. Karren up to 50 cm deep have developed in this zone. A weaker fissured zone was also found on the structural ter- race in a NS direction. Fractures in the NWSE direction are most pronounced be- tween cones and across the cone located at the edge of the canyon. In this fissured zone, deep karren have formed on the cones and on the edge of the structural terrace above the canyon (Fig. 2.8.7.). On the southern side of the canyon, above the structural terrace below which the canyon begins, a fracture zone in the NWSE direction is clearly visible in the walls of a large sinkhole (Fig. 2.8.8.). Zhongzhai On the north-eastern side of the Yezhong plateau, near Zhongzhai village, we found Nadja Zupan Hajna Effect of Geological Structural Elements ... Fig. 2.8.6. Low cone summits are located on the structural terrace below Monkey reserve administration, at the beck upper part of the canyon is seen and the top of the Yezhong plateau (Photo. N. Zupan Hajna). kitkras2.p65 3.12.98,9:20 202 Black 203 2 Nadja Zupan Hajna Effect of Geological Structural Elements ... Fig. 2.8.7. Deep karren by the fractures in the NWSE direction directly next to the edge of the structural terrace that overhangs the 700 m deep Beipanjiang river canyon (Photo. N. Zupan Hajna). Fig. 2.8.8. A strong fissured zone in the NWSE direction in the limestone on the structural terrace of the southern slope of the Beipanjiang river canyon (Photo. N. Zupan Hajna). the entrance to a karst valley. The valley lies approximately 1750 m above sea level and is surrounded by cone summits over 2000 m high (Fig. 2.8.9.). There are individual 100 m high cones scattered around the bottom of the valley (Fig. 2.8.10.). In the area we traversed, the valley was generally oriented in a NS di- rection, with side valleys connecting to it from the east and west sides (Fig. 2.8.11.). The valley descends in stages towards the Beipanjiang canyon (Fig. 2.8.12.). There is no large water flow in the valley but small flows, which soon disappear in the valley bottom, run from side valleys. Four general fault zone directions NS, NE-SW, NWSE, and EW have affected the valleys orientation and the formation of cone summits in the valley bottom and edges. This part of the Yezhong plateau is structured of Early Permian limestone dolomitised in some places and also con- taining chert. The layers dip to the SW, 240/10 (15) in the eastern and southern parts of the valley and, in the south-eastern part of the valley, to the SE, 150/5 (Fig. 2.8.13.). A large number of large and small cave entrances in the slopes of the cones in the kitkras2.p65 3.12.98,9:28 203 Black 204 2 Nadja Zupan Hajna Effect of Geological Structural Elements ... Fig. 2.8.9. Karst valley by the Zhongzhai village 1750 m above sea level surrounded by cone summits over 2000 m high. Legend: 1 - Cave I, 2 - Cave II, 3 - Cave III. Fig. 2.8.10. About 50 m high cones are scattered along the bottom of the Zhongzhai valley (Photo. N. Zupan Hajna). kitkras2.p65 3.12.98,9:28 204 Black 205 2 Nadja Zupan Hajna Effect of Geological Structural Elements ... Fig. 2.8.11. The Zhongzhai valley has generally NS direction (Photo. N. Zupan Hajna). Fig. 2.8.12. The Zhongzhai valley descends towards the Beipanjiang river canyon (Photo. N. Zupan Hajna). kitkras2.p65 3.12.98,9:28 205 Black 206 2 Nadja Zupan Hajna Effect of Geological Structural Elements ... main valley and side valleys are visible. The entrances are located at the following heights: first at the bottom of the valley at the contact of the cone base and valley bot- tom, the second at about 100 m above the valley bottom, and the third at about 200 m above the valley bottom. There is water in the caves at the valley bottom, while the caves in the valley slopes show signs of past groundwater levels. Side valley There is a small creek spring near the road leading from a plateau over 2000 m above sea level near the Majiachong village through a smaller side valley to the main valley near Zhongzhai village. About 100 m above the valley bottom, in its northern slope, two cave entrances showed promise of leading to a larger cave (Fig. 2.8.14.). The first, Cave I., terminated after a few meters in a passage filled with sediments. We measured the cave and drew a map of it. We also measured the directions of the Fig. 2.8.13. Dip of beds and strikes of tectonic structures in the Zhongzhai karst valley. Intensity is expressed by length of the bars. Fig. 2.8.14. Large cave entrance in the slope of the side valley (Photo. N. Zupan Hajna). kitkras2.p65 3.12.98,9:28 206 Black 207 2 Nadja Zupan Hajna Effect of Geological Structural Elements ... geological structures. The second cave, Cave II., was essentially a huge abri filled to the top with sediments. Cave I. The cave passage is oriented to the north and follows the fractures in a NS direction, which is clearly visible from the entrance to the end of the cave. The cave entrance opens in the fractures in a NWSE direction 330- 150 to 320-140, that is in the direction of the side valley. Lesser fractures in the EW direction are also nicely visible. The cave ends blocked with sediments, there are also large quantities of remains of old conglom- erate on the walls. The cave ceiling is le- veling, which points to the fact that the cave was once filled to the top with sediments. Cave II. The entrance to the cave is located in a wall that runs in the same direction as the fractures, that is EW, approximately 100 m above the valley floor. It is a wide escarp- ment filled with allochthonous sediments of a yellow color. Main valley In the area where the side valley de- scribed connects to the main valley, at Zhongzhai village, the creek submerges in a smaller depression below a cone through which a fault cuts with a dip of 130/70 (Fig. 2.8.15.). A cone approximately 100 m high rises on its southern side. It is structured of a light-colored, thick-layered limestone in the lower part, and in the upper part of a darker, stratified limestone with individual sheets of chert. The limestone layers dip in the SW direction, the strata dip is 240/10. This cone is interesting because the entrance into the smaller cave lies in its slope and also due to the fact that it is bisected by a longitudinal opening with a few meters wide vertical walls (Fig. 2.8.16.). The trough is limited by its surfaces in the EW direction and is filled to the top with autochthonous and allochthonous me- chanical sediments. In the short time avail- able we were not able to establish whether it is a smaller tectonic opening filled with sediments from the surface or a roofless cave passage filled with sediments. To the north, on the lower part of the cone, an area of 1 m deep karren had developed on its sum- mit in a fissured zone in the EW direction. On the pass between the area mentioned and the crest which rises towards the east and summits over 2000 m high, we find a clearly visible broken zone in the NS direction. The fissured zone is especially evident on the neighboring cone with deep karren in the lower part where the limestone is more stratified (Fig. 2.8.17.). Cave III. The entrance to the cave is located in the middle of the slope of a cone with a Fig. 2.8.15. A fault with a dip of 130/70 cuts the cone above the swallow-hole of the periodical creek (Photo. N. Zupan Hajna). kitkras2.p65 3.12.98,9:28 207 Black 208 2 Nadja Zupan Hajna Effect of Geological Structural Elements ... Fig. 2.8.16. The cone with Cave III. and roofless cave on the top of the summit, Zhongzhai (Photo. N. Zupan Hajna). Fig. 2.8.17. Fissured zone in the EW direction are especially evident with karren in the thick stratified limestone (Photo. N. Zupan Hajna). kitkras2.p65 3.12.98,9:28 208 Black 209 2 Nadja Zupan Hajna Effect of Geological Structural Elements ... trench and a fracture zone in the direction 320-140. The short cave passage lies in the EW direction. The wall is cracked with small fractures in the 210-30 direction. The cave is 8 m long, and terminates in gray con- glomerate that fills the passage to the top. Majiachong The valley by the village Majiachong on the Yezhong plateau follows a NESW di- rection (Fig. 2.8.18.). The bottom of the valley is 2000 m above sea level, the highest cone summits around it are over 2200 m above sea level (Fig. 2.8.19.). There are individual cones at the bottom of the valley. The early Permian limestone which this area is structured of, came into contact with Early Permian ba- salt on the north-eastern edge of the valley. We climbed to some of the summits to the south of the village and these were from 180 to 260 m high. Fig. 2.8.18. Valley by Majiachong village 2000 m above sea level is lying in the NE-SE direction. Legend: 1 - Cone I, 2 - Cone II The highest reaches a height of 2265 m, there are passes at various heights between the cone summits. The dip of the limestone layers here is 300/20. The lower parts of the cone summits, below the pass at a height of 2100 m, are formed of layers of dense black limestone, the upper part of the layers of white limestone with lenses of chert. The contact between them is heavily tectonised. There is a high density of calcite veins in the black limestone at the contact represented by a vein of crystal calcite approximately 10 cm thick. In pockets and over large areas on the cone slopes a brown weathered deposit, rich with quartz, was found. The main fissured zone across the cone has a NW-SE direction, 310-130 , and a weaker fissured zone in the NS direction, running in the 350-170 direction. Black limestone at the bases of the cones, below the pass, are fractured in the NESE direc- tion, 250-70, the limestone was crushed between the faults of the same orientation (Fig. 2.8.20.). kitkras2.p65 3.12.98,9:28 209 Black 210 2 Nadja Zupan Hajna Effect of Geological Structural Elements ... Fig. 2.8.19. Majiachong valley encircled by cone summits over 2200 m high (Photo. N. Zupan Hajna). Fig. 2.8.20. Dip of beds and strikes of tectonic structures in the Majiachong valley, Yezhong plateau. Intensity is expressed by length of the bars. kitkras2.p65 3.12.98,9:29 210 Black 211 2 The following structural elements have been measured from the Majiachong village towards the Beipanjiang canyon, that is to- wards the SE, over the Yezhong plateau with its cone summits which reaches over 2000 m above sea level limestone strata dip 230/18; and three main fracture directions, the first, NS, which turns to 350-170, the second, NWSE and the third, NE-SE (Fig. 2.8.21.). Taishaba At Taishaba, south of the city of Liu- panshui, on a plateau over 2000 m high, cone karst has developed in Early Permian beds. A creek flows past the village, but was dry during our stay. We followed its bed to the swallow-hole in the lowest depression between the cone summits. At the last swal- low-hole, fractures in the NESW direction, 210-40, were evident. In Early Permian limestone, from which the cones at the north-eastern edge of the village are structured, the strata dip is to- wards the SW. The dip of the strata is be- tween 200/20-25 and 220/20. A strong fis- sured zone is evident and cuts the cone in the NESW direction, 230-50 (Fig. 2.8.22.). The direction of the main fissured zone across the pass between the cones is NS. The two cones are limited by weaker frac- tures in the EW direction on the northern and southern side. Both fissured zones di- vide the two cones where all three men- tioned directions of tectonic deformations cross. The rock there is crushed. Conclusion The measurements of individual geo- logical structures indicated that the passes between individual cones usually occur at the intersection of a number of differently oriented fault zones or in zones with heav- ily disintegrated rock. As rock is crushed it also becomes less resistant, therefore this is where more intense dissolution happens. Nadja Zupan Hajna Effect of Geological Structural Elements ... Fig. 2.8.21. Dip of beds and strikes of tectonic structures on the Yezhong plateau, between the village of Majiachong and the Beipanjiang river canyon. Intensity is expressed by length of the bars. kitkras2.p65 3.12.98,9:29 211 Black 212 2 Nadja Zupan Hajna Effect of Geological Structural Elements ... This form of dissolution is nevertheless weaker than the dissolution which takes place simultaneously at the groundwater level at the base of the cone. The ground- water level regulates the development of the level area between the cones and thus divides them. The plain may be flooded oc- casionally, according to the water level vari- ation. Dissolution processes form the cones which may be divided by a flood plain, by passes or cockpits which develop in zones with heavy tectonic breaking of the rock, and thus where selective corrosion is stronger. Cones with separate summits and the same base may develop, the rock is low- ered between the summits because zones with more disintegrated rock are located there. In passes and depressions between the cones, a heavier accumulation of me- chanical sediments or soil is often present, additionally accelerating carbonate rock dissolution. We may conclude that where a cone forms, that is where rock remains, depends to a greater extent on the distribution of fault zones and to a lesser extent on the dif- ferences in rock lithology, the main proc- ess being selective corrosion. Fig. 2.8.22. Dip of beds and strikes of tectonic structures at Taishaba village. Intensity is ex- pressed by length of the bars. kitkras2.p65 3.12.98,9:29 212 Black 213 2 SAMPLE LOCATION A.S.L. FIELD DESCRIPTION SF Stone Forest, behind the hotel 1800 m red soil LIU 1 Bajiazhai, pocket 1850 m red loam LIU 2 Bajiazhai, pocket 1850 m yellow sand BAI 1 Baipanjiang, near the Bridge 960 m brown loam BAI 2 Baipanjiang, southern side 1350 m red- brown soil ROB 1 Baipanjiang, terrace edge 1510 m yellow loam ROB 2 Baipanjiang, terrace edge 1510 m red loam ROB 3 Baipanjiang, karren on cone 1565 m brown soil ROB 4 Baipanjiang, Monkeys Head 1620 m red soil ZHO 1 Zhongzhai, Cave II. 1850 m sand, loam ZHO 2 Zhongzhai, Cave III. 1830 m sand, pebbles ZHO 3 Zhongzhai, in front of Cave III. 1830 m loam, limonite crust ZHO 4 Zhongzhai, roofless cave 1850 m laminated loam MAI 1 Maijachong, Cone I. 2150 m brown loam MAI 2 Maijachong, Cone II. 2150 m brown soil MAI 3 Maijachong, main road 2150 m basalt TAI 1 Taishaba, pass between cones 2270 m brown soil TAI 2 Taishaba, cone slope 2270 m red-brown soil TAI 3 Taishaba, swallow-hole 2195 m yellow-brown soil XIN 1 Xingchang, Cave 1720 m yellow loam XIN 2 Xingchang, slope above village 1800 m yellow weathered loam XIN 3 Xingchang, slope above road 1820 m yellow loam Table. 2.9. Location and field description of samples analysed by x-ray diffraction technique. Introduction Sediments in the karst relief and caves of south-east Yunnan and north-west Guizhou seemed interesting to me for the reason that they do not differ in colour from sediments in the karst of Slovenia. Sedi- ments and soils in the karst of Slovenia and south China are mainly red and yellow. These facts resulted my interest in mineral composition of karst sediments in south China. The basins of south China are in a great part filled by a thick layer of red sediments. Red soil developed in a tropical climate of sediments originated from the 2.9. CLASTIC SEDIMENTS FROM KARST OF SOUTHEAST YUNNAN AND NORTH WEST GUIZHOU Nadja Zupan Hajna weathered remains of non carbonate rocks, schist, sandstones, Upper Permian basalt, Eocene lake sediments etc. (Zhang 1984). Some of them dont exist in that part of China anymore. Weathered remains are enriched on silico-ferrous minerals like quartz, opal, amorphous silica, goethite, hematite, sericite, siderite etc. (Maire & Pomel 1995). Sediments are not captured just in big basins but also in smaller depres- sions of cone karst and in caves. The relief of SE Yunnan is in great part covered by thick layer of red soil probably developed from basalt and Eocene sedi- ments (Zhang 1984). Clastic sediments, Nadja Zupan Hajna Clastic Sediments from Karst of Southeast Yunnan ... kitkras2.p65 3.12.98,9:29 213 Black 214 2 found in the karst relief of NW Guizhou, are in most cases of a brown colour and origi- nate from weathered basalt, quartz sand- stone and rock of the coal series. The samples in which was defined min- eral composition represent clastic sedi- ments that differ very much in terms of col- our, texture and consistency. The quantities of each sample were small due to transport limitations. Beside the samples of clastic karst sediments of south-east Yunnan and north-west Guizhou, samples of basalt and quartz sandstone were also taken. These are the two most common forms of non-car- bonate rock in this area which come into contact with carbonate rock and are thus the possible original rock for their forma- tion. Altogether we took 22 samples from across a vast area (Table. 2.9.). For this rea- son we gained an impression only of their composition and not of their origin. X-ray of the samples was performed at the Institute of Geology at the Faculty of Natural Sciences and Technology in Ljub- ljana with a Phillips diffractiometer using the x-ray diffraction technique. The shoot- ing conditions were a Cu K a anode, auto- matic divergence slit, the area of shooting was at angle 2Q from 4 to 70 and the size of the step was 0.02. All the samples con- tained so many different minerals that the reflections covered each other thus making it difficult to define them. It was not possi- ble to determine lower reflections in some cases and we assume that these belong to the minerals that were scarcer in the sam- ples. Plagioclases, feldspar, mica minerals and phosphates were in such a low quan- tity that there precisely determination was not possible. The quantity of minerals is given in their respect to the height of the main peak of particular mineral and it is relative. Mineral composition of samples is represented in Fig. 2.9.8.. South-west Yunnan (Lunan and Xichou) One third of Yunnan province consists of carbonate rock, mostly from the Late Paleozoic and Triassic. In Lunan area, the Nadja Zupan Hajna Clastic Sediments from Karst of Southeast Yunnan ... Fig. 2.9.1. Red soil covers slopes of the cone summits, yellow-coloured clastic sediments can be residue of sediments from denuded cave (Photo. A. Mihevc). kitkras2.p65 3.12.98,9:29 214 Black 215 2 karst relief is covered with a thick layer of red soil beneath which stone forests have developed in Lower Permian limestone and dolomite. The height above sea level in this area varies from 1100 to 1950 m. Upper Permian basalt has covered Lower Permian carbonate rock and Eocene lake sediments. These rocks are the possible source rock for the development of the red soil. From Lunan to the south, the plateau be- comes cut through with valleys, the cone summits on plateau are encircled and partly covered by red soil. Xichou, which lies in the far south-eastern part of Yunnan, is an area of cone karst and has formed in Lower and Upper Paleozoic limestone and dolo- mites. It has an ear-like pattern of carbon- ate rock, large depressions lie in the mid- dle of the ear-like structure and small ones on the edge (Song Lin Hua & Liu Hong 1992). Red soil covers the summits and slopes of the cone summits. Yellow-col- oured clastic sediments can be found in caves, in some places at the bottom of de- pressions, and sometimes in irregular patches on the slopes of cones (Fig. 2.9.1.). The yellow colour of the sediments indi- cates that the sediments were not in the oxidation zone during the warm climate, preventing iron oxides from transforming into hematite and turning red. The presence of yellow-coloured sediments in patches and their colour point to the possibility that they used to be cave sediments which have subsequently surfaced. Lunan Stone Forest Sample SF Sample SF consist of red soil from the Lunan Stone Forest (Fig. 2.9.2.) containing individual chips of weathered limestone. It was taken behind the hotels in construc- tion-pit. The sample is mostly comprised of quartz 96 %, chlorite 2 %, muscovite 1 %, kaolinite and hematite are present in traces. The minerals present do not indicate the origin of the sample, since these are miner- als present in the weathered product of dif- ferent parent rocks. The quartz probably derives from Eocene lake sediments and the hematite points to the fact that the sediment was formed in a warm climate. North-west Guizhou (Panxian and Liupanshui) The province belongs to the eastern part of the Yunnan-Guizhou plateau, 75 % of the area is carbonate rock of the Carboniferous, Permian and Triassic ages. The oldest rock in north-west Guizhou is of the Middle Carboniferous and is rep- resented by light-coloured massive and thick-layered limestone and dolomites. The Lower Permian begins with quartz sand- stone and marl, in some places containing thin layers of poor quality coal. These are succeeded by black limestone with marl and schist, and above the Lower Permian Nadja Zupan Hajna Clastic Sediments from Karst of Southeast Yunnan ... Fig. 2.9.2. In some places red soil covers limestone karren almost to the top, Lunan Stone Forest, behind the hotels (Photo. N. Zupan Hajna). kitkras2.p65 3.12.98,9:29 215 Black 216 2 lies grey and white limestone which is dolomitised in some places. The Lower Permian ends with vast paleokarst. The Up- per Permian begins with thin-layered dark grey and black limestone interchanging with main coal layers, marl and schist, and quartz sandstone; all of the layers are covered with basalt. Basalt is followed by rock from the Lower Triassic, with red marl at the bottom, followed by grey limestone and dolomites. The Middle Triassic is represented by breccia limestone with marl and schist at the bottom. Clastic sediments, found in the karst relief and caves in NW Guizhou, most probably originate from weathered basalt (Fig. 2.9.3.) and quartz sandstone. Shizilu In the south-eastern part of Guizhou, south of the city of Panxian, the karst polje Shizilu lies 1680 m above sea level. It is sur- rounded by cone summits up to 200 m high. The cone karst of this area is composed of Lower, Middle, Upper Carboniferous lime- stone, Lower Permian limestone and marl with some coal and Upper Permian basalt and marl with main coal layers and at the end Lower Triassic sandstone. A sinking creek flows across the polje carrying weath- ered remains of previously mentioned rocks with it. Polje is covered by grey-yel- low sediments and on the slopes of the cones red soil prevailed (Fig. 2.9.4.). The cave Huoshao is located between two passes, 1750 m above sea level. Basalt, quartz and limestone pebbles were found in the cave. Many flow-stone pallets and helectites, nice calcite crystals up to 2 cm in size, which grew in line with the water level, were found at the end of the cave. Most of the sediments from the karst sur- face of NW Guizhou were investigated in the vicinity of the city of Liupanshui. The samples were taken from the stone-pit near the small village of Bajiazhai, and north of the city from Swallow Cave next to the natu- ral bridge Tianshengqiao, from the cave and the surface around the village of Xingchang, Nadja Zupan Hajna Clastic Sediments from Karst of Southeast Yunnan ... Fig. 2.9.3. Weathered basalt from the Yunnan-Guizhou plateau, from the border between provinces of Yunnan and Guizhou (Photo. N. Zupan Hajna). kitkras2.p65 3.12.98,9:29 216 Black 217 2 from the surface around the village of Taishaba and of Majiachong and from caves and the surface around the village of Zhongzhai, and from the slopes of the Beipanjiang river canyons. From the above a review of clastic sediments that occur on the Yezhong plateau, which has an average height of 2000 m, and above Beipanjiang river was made (Fig. 2.8.3.). Bajiazhai In the small village of Bajiazhai by the city of Liupanshui at 1850 m above sea level, two samples from a cone with two summits cut by the construction of a road and by a stone-pit were taken. The structure of The cone is built of Lower Permian limestone which has become quite dolomitised (Fig. 2.8.1.). Two karst pockets were open in the wall, both filled with red loam, where it con- tacted with the rock large quantities of yel- low sand were found . Sample LIU 1 Sample is red loam from a karst pocket from a cone with two summits. Sample con- tains quartz 32 %, montmorillonite 41 %, gibbsite 9 %, dolomite 7 %, kaolinite 4 %, chlorite 3 %, and hematite 3 %. This red loam is probably residue of well developed paleosoil. Sample LIU 2 Sample is yellow sand from the contact between red loam and neighbouring rock. Yellow sand contains mostly dolomite 89 %, in quantity succeeded by quartz 7 %, cal- cite, gibbsite and mica 1 %, kaolinite, plagioclase and hematite were in traces. Regarding on mineral composition, this yel- low sand is result of dolomite weathering in the contact with red loam. Tianshengqiao In Swallow cave near big natural bridge, Tianshengqiao, about 15 m above the actual stream a maze of older phreatic channels is filled by sediments. Gravel, sand and silt indicat older infill of the cave. From the small phreatic channel at the top of high gallery sample of sand mixed by silt was taken. Nadja Zupan Hajna Clastic Sediments from Karst of Southeast Yunnan ... Fig. 2.9.4. Karst polje Shizilu is covered with grey-yellow sediments but on the slopes of the cones red soil prevailed (Photo. N. Zupan Hajna). kitkras2.p65 3.12.98,9:29 217 Black 218 2 Sample SWC Sample from Swallow cave is comprised of quartz 65 %, feldspar 9 %, chlorite, dolo- mite 5 %, muscovite 4 %, calcite 35 %, augite 3 % and niter (saltpetre) 3 %. Quartz, chlorite, muscovite, feldspar and augite were brought into the cave by the stream from noncarbonate rocks. Dolomite and calcite are originated from cave walls. Beipanjiang The Beipanjiang river canyon is cut into the karst plateau Yezhong which is over 2200 m high. We can trace carbonate rock and two coal series from the Middle Carbon- iferous to the late part of the Upper Permian in the approximately 1400 m deep canyon. Basalt covered all this rock in the Upper Permian. Various clastic sediments could be found on the surface and in caves. On the surface brown-yellow and red soil and in the caves grey and yellow sand, loam and pebbles are most common sediments. Sample BAI 1 Sample of brown loam was taken from a fracture which was subsequently widened by corrosion, beside the New bridge cross- ing the river at 970 m above sea level. The brown loam contained quartz 60 %, mont- morillonite 22 %, chlorite 5 %, hematite 3 %, and calcite, muscovite, kaolinite, goethi- te and feldspar at 2 % each. Sample BAI 2 In the southern part of the canyon, on a structural terrace 1350 m above sea level, we found a larger accumulation of red- brown soil (Fig. 2.9.5.) with quartz nodules and limonite collections in it. Soil sample Bai 2 contained quartz 47 %, goethite 16 %, chlorite 13 %, hematite and kaolinite 8 % each, phosphate 5 % and gibbsite 4 %. Individual low cone summits have formed on a structural terrace around 1500 m above sea level. Varicoloured clastic sediments were found between fractures running across the structural terrace and summits in diverse directions. We took sam- ples of yellow and red loam from between two cones on the edge of Beipanjiang river canyon. The positions of the two samples were only a few meters apart. Sample of brown soil from a fracture in a cone located above the two samples was also taken. The next sample of red soil was taken from the part where the structural terrace starts to rise towards the slope of the Yezhong pla- teau, that is from karren bellow the reserve administration. Sample ROB 1 Sample of yellow loam is very likely the weathering product of quartz sandstone which could be find up the slop of Yezhong Nadja Zupan Hajna Clastic Sediments from Karst of Southeast Yunnan ... Fig. 2.9.5. In the southern part of the Beipanjiang river canyon, on a structural terrace 1350 m above sea level, a larger accumulation of red-brown soil (Fig. 2.9.5.) with quartz nodules and limonite collections in it exists (Photo. F.Gabrovek). kitkras2.p65 3.12.98,9:30 218 Black 219 2 plateau. Sample comprised of quartz 88 %, chlorite 7 %, kaolinite 2 %, mica, goethite, hematite and gibbsite 2 % each. Sample ROB 2 Sample of red loam containing quartz 80 %, chlorite 11 %, kaolinite and gibbsite 3 % each, hematite 2 % and goethite 1 %. Sample ROB 3 Sample of brown soil from a karren on the cone, by the edge of the canyon, com- prised of quartz 70 %, montmorillonite 14 %, calcite 5 %, chlorite 3 %, gibbsite 2 % and dolomite, mica, kaolinite feldspar, goethite and hematite 1 % each. Sample ROB 4 Sample of red loam from karren near The Monkeys Head, below the reserve ad- ministration, comprised of quartz 63 %, chlorite 13 %, goethite 9 %, gibbsite 8 %, kaolinite 5 %, and phosphate 3 %. Samples ROB 1 and ROB 2 have almost the same mineral composition, they were taken just few meters apart and their col- our is different. They are probably weath- ered remains of quartz sandstone which is located further on the slope of canyon and it belongs to Permian coal series. Samples of red-brown loam and soil, including sam- ples BAI 1 and 2, have very similar mineral composition which shows on formation in tropical climate. Zhongzhai The karst valley near the village of Zhongzhai at 1750 m above sea level is sur- rounded by cone summits at a height of over 2000 m. Two caves have large en- trances in a small valley connecting to the northern slope of the Beipanjiang river can- yon by the Majiachong road. Nadja Zupan Hajna Clastic Sediments from Karst of Southeast Yunnan ... Fig. 2.9.6. Pebbles mixed with yellow sand in the entrance part of the Cave II. (Photo. N. Zupan Hajna). kitkras2.p65 3.12.98,9:30 219 Black 220 2 Cave I. In at the entrance in Cave I. Holocene gravel and fallen rocks were found and also, on the bottom, lightly attached rubble with individual animal bones. There are remains of conglomerate on the walls of the cave pointing to the fact that the cave was filled with sediments to the ceiling. The sedi- ments are composed of cobbles 10 cm in size, sand and loam. The ceiling is leveled where it is in contact with the sediment. Cave II. Cave II. is filled with allochthonous yel- low-coloured sediments to the roof. Layers of pebbles (Fig. 2.9.6.), sand and laminated loam exchange. There are a number of sta- lactites, hanging at the entrance part. Sample ZHO 1 Sample is of yellow laminated loam from Cave II., which was located beneath the layer with pebbles and contains quartz 55 %, chlorite 23 %, montmorillonite 8 %, feld- spar 5 %, goethite 4 %, kaolinite and augite 2 % each. Cave III. The entrance to Cave III. is in a cone lo- cated on the eastern slope of the main val- ley by the village of Zhongzhai. In the cave is a large quantity of white decaying flow- stone and some fallen rocks. The profile of the sediment at the end of the cave is 2 m high, the matrix connecting the small peb- bles are sandy, cementation is weak. Sample ZHO 2 The mineral composition of the con- glomerate sample from Cave III. is quartz 36 %, montmorillonite 32 %, calcite 19 %, feldspar 3 %, chlorite and plagioclase 2 % each and kaolinite and goethite 1 % each. The cone with Cave III. is bisected by a wide longitudinal opening with vertical walls. The opening, formed by fractures running in an EW direction, is filled almost Nadja Zupan Hajna Clastic Sediments from Karst of Southeast Yunnan ... to the top with mechanical sediments. Peb- bles, sand and loam in belts with higher con- centrations of limonite are covered by fallen blocks and gravel from the slope of the cone. Whether this is a small tectonic opening filled with sediments from the sur- face or a roofless cave passage filled with sediments to the top could not be deter- mined in such a short period of time. We took two samples from this location. Sample ZHO 3 The was a sample of the brown loam with pebbles and limonite crust in a longi- tudinal opening of the same height as the entrance to Cave III, the minerals in the sam- ple were as follows: quartz 48 %, goethite 37 %, chlorite 8 % and montmorillonite 6 %. Sample ZHO 4 The second was a sample of the lami- nated loam from the trench directly be- neath the pass. The sample contains quartz 59 %, montmorillonite 21 %, goethite 10 %, chlorite 7 %, feldspar 2 % and kaolinite 1 %. Last two samples have little different mineral composition like previous one spe- cially in a differ goethite content. Majiachong Near the village Majiachong, in the southern part of the valley on a plateau over 2000 m above sea level, on a cone summit we found patches of brown weathered de- posit, probably quartz sandstone or from in situ limestones rich with chert nodules. The accumulation of this weathering de- posit was bigger depressions and on level parts of the slope. Samples were taken on Cone I and Cone II (Fig. 2.8.18.). Sample MAI 1 Sample of the brown soil was taken on the Cone I, 2150 m above sea level. Sample contains quartz 46 %, goethite 22 %, kitkras2.p65 3.12.98,9:30 220 Black 221 2 kaolinite 20 %, chlorite 10 % and mont- morillonite 1 %. Sample MAI 2 Sample of the brown sandy loam with bigger pieces of quartz sandstone was taken on the Cone II, 2185 m above sea level (Fig.2.9.7.). Sample contains quartz 65 %, montmorillonite 18 %, muscovite 3 %, chlorite 4 %, kaolinite 7 %, chlorite 4 %, muscovite and gibbsite 3 % each and hematite 1 %. These two samples are different in mineral composition specially in the re- gards of containing goethite and also gibbsite. Maybe the origin is for both the same from weathered quartz sandstone or from in situ limestones rich with chert nodules but the diagenesis of these two de- posits was different. Sample MAI 3 Sample Mai 3 was taken at the contact of Lower Permian limestone and basalt and was originally thought to be basalt though this subsequently proved not to be the case. The mineral composition of the sample is quartz 47 %, plagioclase (anorthite) 18 %, chlorite 15 %, augite 11 %, muscovite and ilmenite 4 % each and kaolinite 2 %. Taishaba Three samples of varicoloured and vari- ously textured sediments from cones in the vicinity of the village of Taishaba were taken. Plateau surrounding of Taishaba is over 2200 m above sea level overlay with cones. In the depression between them lies bigger accumulation of soil and slops of cones are almost bare, there is some soils captured among karren. Sample TAI 1 Sample Tai 1 is from brown soil from the pass between the first and the second cone behind the school. The sample contains quartz 87 %, chlorite 5%, muscovite 3 %, kaolinite and gibbsite 2 % each, plagioclase 1 % and hematite is in traces. Sample TAI 2 Sample Tai 2 is red-brown soil from the lower part of the slope of the third cone behind the school. The sample contains quartz 80 %, chlorite 12 %, muscovite and gibbsite 2 % each, kaolinite and feldspar 1 % each, dolomite and hematite are in traces. Sample TAI 3 Sample Tai 3 is loam from the swallow- hole beneath the village. The sample con- sists of quartz 83 %, goethite 8 %, chlorite 4 %, gibbsite 3 % and mica 2 %. Mineral association in samples of all localities is almost the same and represents the soil formation in tropical climate. Nadja Zupan Hajna Clastic Sediments from Karst of Southeast Yunnan ... Fig.2.9.7. Brown sandy loam with bigger pieces of quartz sandstone in karst pocket on the Cone 2 (Photo N. Zupan Hajna). kitkras2.p65 3.12.98,9:30 221 Black 222 2 Xinchang Xingchang village is situated cone-de- pression karst type 1600 m to 1900 m above sea level. Samples of yellow loam were taken on the cone slope above village Xingchang and in the cave below village. Sample XIN 1 Yellow loam from middle part of the cave contains quartz 94 %, montmorillonite 3 %, muscovite 1 % and chlorite, kaolinite and goethite are in traces. Sample XIN 2 Accumulation of yellow weathered loam on slope above village was mixed with some chert pebbles comprises quartz 92 %, montmorillonite 4 %, muscovite and chlo- rite 2 % each and kaolinite 1 %. Sample XIN 3 Yellow loam on the slope above road consists of quartz 92 %, montmorillonite 3 %, muscovite and gibbsite 2 %, chlorite and kaolinite 1 %. Nadja Zupan Hajna Clastic Sediments from Karst of Southeast Yunnan ... Fig.2.9.8. Mineral composition of samples from SE Yunnan and NW Guizhou. Legend: SF, LIU 1, LIU 2, SWC, BAI 1, BAI 2, ROB 1, ROB 2, ROB 3, ROB 4, ZHO 1, ZHO 2, ZHO 3, ZHO 4, MAI 1, MAI 2, MAI 3, TAI 1, TAI 2, TAI 3, XIN 1, XIN 2, XIN 3 are samples; minerals: K quartz, Ca calcite, D dolomite, Mu- muscovite, M mica, Ka kaolinite, Mo montmorillonite, KL chlorite, F- feldspar, PL plagioclase, G goethite, H hematite, Gi gibbsite, Av augite, N niter, Ph phosphate, IL ilmenite. kitkras2.p65 3.12.98,9:30 222 Black 223 2 Nadja Zupan Hajna Clastic Sediments from Karst of Southeast Yunnan ... Regarding on mineral composition yel- low loam on the surface and in the cave have had the same origin. They probably originated from weathered rests of lime- stones rich with chert nodules (Fig.2.5.3.). Conclusion The samples represent very different clastic sediments, that is in terms of colour, texture and consistency. As they represent a large area and they are few in number, the information concerning their mineral com- position offers only a small insight into their origin (Fig.2.9.8.). A large number of the minerals in the samples are secondary, formed during the processes of weathering, and some of them are primary minerals which often have their origin in quartz sandstone and are the insoluble remainder of limestone rich in chert. The mineral hematite and gibbsite indicate the forma- tion of sediments in a tropical climate. As already pointed out in the introduc- tion, karst sediments in Slovenia and in southern China are of the same colour, in mineral composition they differ primarily in additional minerals, which is understand- able. Quartz is the most common and pro- fuse mineral in the sediments, in Slovenia as well as in the samples described. This is be- cause it is the most resistant mineral and rep- resents the remainder of the weathering of a large number of various rock types. The alumnosilicates are also resistant, but in time transform into clay minerals and chlorites, which are the most common minerals to form during weathering processes and are widespread, which is why we find these min- erals in sediments in Slovenia and also in southern China. The primary minerals are different, they are most commonly heavy minerals which are characteristic of the rock of origin and this varies from case to case. Thus we find in the sediments of the south- ern Chinese karst, minerals that are charac- teristic of basalt weathering and other min- erals that are rare in sediments in the karst of Slovenia. I did not have enough samples to allow me to draw more important con- clusions concerning the origin of sediments in SE Yunnan and NW Guizhou and their mineral composition. The colour of the sediments is more a reflection of the conditions under which the sediment formed and survived and less of their mineral composition. kitkras2.p65 3.12.98,9:30 223 Black 224 2 Presented below are some traditional forms of land use in mountainous areas of the Chinese karst in the provinces of Yunnan and W Guizhou. The bottoms of karst depressions, where there is more soil and where the soil is continuous, are uti- lized as small or large fields. If irrigation is possible, rice paddies are prevalent; corn, tobacco, hemp and cotton grow where there is no water for irrigation. The soil cover is not continuous on the slopes, but the surface is nonetheless culti- vated. The prevailing form of cultivation is digging and turning the soil with special narrow shovels and the planting of indi- vidual plants, mostly corn, between stone blocks. We find this type of use on slopes with an incline of around 40. Pressure on the land is increasing and this causes the colonization of areas with poor natural con- ditions to continue. Introduction Carbonate rock is spread over 1/10 of Chinas territory, or 910,000 km 2 , which is double the area covered with loess. In the provinces of Guanxi, Guizhou, Yunnan, and in parts of the provinces of Sichuan, Hubei, Guangding, Hunan, Shandong and Hunan, which have a population of a few hundred million, typical karst developed in carbon- ate rock. In most karst areas agriculture is im- peded due to the natural features of karst, resulting in karst areas being poor, sparsely settled and underdeveloped. The main limi- tations on agricultural use are soil defi- 2.10. LAND USE IN MOUNTAINOUS KARST AREAS Andrej Mihevc ciency and/or rocky surface and aridity of the surface caused by karst water move- ment characteristics. Karst in China extends from the tropi- cal belt to the temperate climate, from hu- mid monsoon climates to the semi-arid to arid interior and from the coast to a height of 5000 m above sea level. The largest part of the karst lies in the tropical and subtropi- cal monsoon climate where corrosion plains by the rivers in the lowlands and karst towers (fengling) are characteristic. The plains are covered with a thick layer of allu- vial deposits and the vicinity of water sources makes intensive irrigation arable farming possible. Higher relief is charac- terized by vast plateaus with cone summits and doline-like depressions and karst plains. The surface is very rocky, except at the bottom of depressions and water is far below the surface, allowing irrigation only at the bottom of plains where karst flows appear. Difficulties concerning water and soil are a very obvious and significant limiting factor for development in the karst of mountainous SW China and are caused by the marked monsoon climate and water and soil difficulties brought about by karst re- lief processes. The poor natural conditions are made worse by some negative effects of overbur- dening karst areas which have triggered heavy degradation processes. Although set- tlement of the mountainous SW Chinese karst is relatively low in comparison with settlement of lowlands, the area appropri- ate for agricultural use is nevertheless over- burdened which is the cause of expansion Andrej Mihevc Land Use in Mountainous Karst Areas kitkras2.p65 3.12.98,9:30 224 Black 225 2 to new land on which agricultural activity is barely possible. Research of agricultural land use in karst relief is important from two perspectives. It can point to the manner in which it may become possible to improve or enlarge ar- able land in karst areas and at the same time prevent the negative effects of agricultural practices. It may also assist in expedient planning of future land use. The other important aspect of research lies in the possibility of comparing existing intensive land use in the Chinese karst with intensive land use in the Mediterranean karst in Europe. These comparisons can as- sist us in studying the history of agricultural systems. Methods of work During our stay we traveled across the Chinese countryside and were able to ob- serve agricultural land use in karst areas. Due to lack of time we were able to observe only some forms, so we primarily observed the adaptation of agriculture to a scarcity of water resources and soil. In this area we observed the utilization of karst relief forms, evaluated the intensity of recent erosion and attempted to evalu- ate the amount of removed soil by compar- ing chipped rocks and subcutaneously formed rock surfaces. We also observed some semi-industrial karst resource uses, for example the pro- duction of lime, stone-pits, coke, and char- coal. These uses in a way complement life in the country and have an important effect due to their dispersion. Due to lack of time we were not able to satisfactorily measure and spatially evaluate these phenomena, which is why the above described observations can only serve to draw attention to phenomena. Traditional land use and relief degradation The SW Chinese mountainous karst can be morphologically described as high pla- teau karst dissected by cone hills and sink- holes similar to depressions, dry valleys, large or small karst plains. Large karst areas are often cut through by deep canyons of allogenous rivers that only cross karst. There are no surface water bodies, all pre- cipitation percolates into the karst, karst springs are present on the fringes of pla- teaus of larger karst depressions. The climate of this part of China is sub- tropical with a characteristic monsoon in- terchange of rainy and dry seasons. The amount of precipitation and the tempera- tures depend on the height above sea level at which the area is located. Despite the considerable amount of precipitation, the relief is dry in its depth because of the long Andrej Mihevc Land Use in Mountainous Karst Areas Fig. 2.10.1. Karst plain in Guizhou province. At the bottom of the karst plain there are thick layers of loamy soil. The submerging creek that crosses the plain has cut a series of terraces into it. The field is intensively used, the main crop being rice. Settlement is limited to the agriculturally inferior fringe of the plain (Photo A. Mihevc). kitkras2.p65 3.12.98,9:39 225 Black 226 2 dry seasons and water runoff. Droughts are frequent and because of water scarcity irri- gation is mostly limited to only the lowest parts of the karst. Settlements are established primarily only in advantageous areas, on the edges of plains, on the bottom of large karst plains or closed depressions. There was enough ar- able land in these areas and karst springs or groundwater near the surface provided an adequate water supply. The growth of large connected settlements was possible here. The two main limiting factors for life in the karst are soil and water. We find soil and water in karst areas only at the bottom of karst basins, plains or large plains by karst rivers. Higher and more dissected karst in- dicates a scarcity of both of the basic re- sources needed for agricultural land use in karst areas. Settlement also expanded to agricultur- ally less adequate areas, where the surface is prevalently rocky, where there is less soil and the water sources are distant. Such ar- eas cover vast expanses in high plateau karst. Although they are not significant in terms of population size and density, their significance lies in the vastness of the area of karst which they cover. It is difficult to determine the settlement of new karst territories and colonization in terms of time-scale. Three periods of rapid population growth are characteristic of China, but there have also been sudden de- clines in population size, usually as a con- sequence of bad harvests or periods of in- stability, or even both at the same time. The process of mountain colonization and population expansion to less favorable ar- eas still continues. The reason for this is a sharp increase in the size of the population, which has doubled in the last 40 years. Houses continue to be built in remote ar- eas and new arable land is being created. In mountainous and hilly areas water rap- idly sinks into the ground, it is also the case in areas where deep karst has developed that most water flows are deep beneath the sur- face. The water emerges at the edge of the karst in large springs, where it is abundant. It is possible to moderate the lack of water through hydrotechnical works. Andrej Mihevc Land Use in Mountainous Karst Areas Fig. 2.10.2. Characteristic landscape of cones with depressions in between. Settlements are sparse due to the rocky surface and limited water resources (Photo A. Mihevc). kitkras2.p65 3.12.98,9:39 226 Black 227 2 The lack of soil is a stronger limiting fac- tor. Soil forms more slowly on limestone than on other rock. The reason for this is that the rock is being dissolved and carried away in the form of a solution and the in- soluble remainder is small. The conse- quence of this is that on the rocky surface, insoluble remainders accumulate in the fractures, and among them we find large bare rocks. Soil scarcity also increases the speed of precipitation runoff causing the surface to be more arid than we would as- sume from the quantity of precipitation. Yellow-brown washed soil, more like loam, prevails on rock surfaces and is pre- served in fractures in the subcutaneous zone widened by corrosion. Organic mate- rial is sparse and the top humus layer of the soil is thin due to rapid decay of organic material and heavy washing. The conse- quence is low retention capacity of the soil and rapid surface water runoff. There is a larger amount of soil on karst rock which has a higher level of insoluble remainder in the rock or where the soil was brought onto the limestone from else- where. Erosion processes may be triggered quickly on such rock and despite the fact that the absolute amount of removed soil is small, the effect is greater because they remove a larger proportion of the existing soil. We can evaluate the proportion of new erosion triggered by man by observing soil erosion on slopes and the accumulation of soil in depressions. Observing forms of sub- cutaneous corrosion in rills and forms which develop in surface rocks which are exposed to atmospheric effects is also an important method. We can presuppose the former soil cover of these rocky surfaces and erosion in the recent past from the dif- fusion of subcutaneous forms. Some cases of land use in karst of China The examples of agricultural land use described apply to the provinces of Guiz- hou and Yunnan. Examples are described Andrej Mihevc Land Use in Mountainous Karst Areas Fig. 2.10.3 Construction of new house in the Yezhong plateau area at around 2000 m above sea level (Photo A. Mihevc). kitkras2.p65 3.12.98,9:39 227 Black 228 2 of land use in different relief areas in W Guizhou and E Yunnan: at the bottom of a karst plain near the city Liupanshui; at the bottom of the small karst plain Shizilu; at the edge of a plain near the Dadong cavern; and also on the highest parts of a high Yezhong plateau near the village of Tai- shaba; near the village of Majiachong; and at the edge of the Yezhong plateau above the Beipanjiang river canyon. Further exam- ples of land use near the city of Xichou in Yunnan are also described. The karst plain of Shuicheng lies at around 1880 m above sea level and is up to 3 km wide and over 10 km long. The flat bottom of the plain is covered by thick soil and several small rivers flow across it and occasionally flood the bottom of the plain. The structurally conditioned edge of the plain passes into an old dissected level area which is up to 300 m high. The bottom of the plain is flat, although individual cone hills (fengling) appear in a number of places. On one of them, barely 10 m high, the old town of Shuicheng has established itself. Today the small town lives in the shadow of the rapidly developing new center Liupanshui. The bottom of the plain is cultivated, rice and vegetables grown on small plots primarily to sell at the Liupanshui market, prevail. The natural bottom of the plain has been changed by irrigation systems. The soil on the plain is brown anthro- pogenic, and probably a few meters thick. Beside the bottom of the plain, surfaces where irrigation is not possible are also farmed as are the surfaces of the slopes of fenlings between clints where yellow- brown soil is present in corrosionally wid- ened cracks. Because of the rapid growth of the city, the nearby ironworks and cement factory and new roads, there are many evident stone-pits, earthworks and new embank- ments which have drastically altered the natural bottom of the karst depression and its water conditions. The Shizilu karst plain by the city of Pan- xian is a dry valley situated 1700 m above Andrej Mihevc Land Use in Mountainous Karst Areas Fig. 2.10.4. Forest fires are common in second half of winter. They are set on purpose, to create a grazing land (Photo A. Mihevc). kitkras2.p65 3.12.98,9:39 228 Black 229 2 Andrej Mihevc Land Use in Mountainous Karst Areas Fig. 2.10.5. The karst plain of Shuicheng, near the village of Bajiazhai. The large plain is farmed intensively because of the soil and the possibility of irrigation. Vegetables for sale at the nearby town market are important. The plants are treated with chemicals (Photo A. Mihevc). Fig. 2.10.6. The Shizilu karst plain. The bottom is turned into terraces, which are irrigated. Slopes with an incline of 30 or less are cultivated. On steeper or rockier surfaces bushes and trees grow, the trees do not reach full size because they are cut for firewood. The trees, which have golden brown leaves, are Ginkgo Biloba (Photo A. Mihevc). kitkras2.p65 3.12.98,9:39 229 Black 230 2 sea level and enlarged by corrosion. Its bot- tom is covered with thick Quaternary de- posits in which creeks have cut a number of terraces. Two smaller creeks flow to the bottom, into each other and then submerge in a swallow-hole at the edge of the plain. There is also a great deal of silt around the swallow-hole, indicating rapid washing of sediments underground. The bottom of the dry valley is cultivated and turned into terraced fields for rice. The creek bed is narrowed and strengthened. The creek is dammed in its upper flow and channeled for terrace irrigation. The slopes above the bottom, in the lower part where the incline is, are first changed into hori- zontal and higher up into sloping terraces. The smallest terraces are only a few square meters in size. The terraces are created in places where there is enough soil and the incline is below 15-20. Slopes with larger inclines do not have terraces, the soil in rills is dug and turned with shovels. The rills in the lower part show signs of chipped rock at the top, the rock is then used to build ter- races or stacked in piles. The comparison of rocks with subcuta- neous and surface corrosion form showed that up to 0.5 m of soil was removed from the slopes. This soil might have been washed away or may have been used for terracing. Land cultivation near Dadong Cavern in Panxian region. The cavern has a large en- trance 20 m above the plain by the creek swallow-hole west of the city of Laochang. The bottom of the valley by the swallow- holes is irrigated, and rice grows in the fields. The slopes above it are utilized for growing corn as they are very rocky. De- spite the slight incline, no terraces are present due to the rockiness, the soil be- tween rills is cultivated using shovels. The highest karst in Guizhou is on a high plateau which stretches from Yunnan to W Guizhou. The Yezhong plateau is between 2000 and 2400 m above sea level in the area of the Beipanjiang river gorge south of the Andrej Mihevc Land Use in Mountainous Karst Areas Fig. 2.10.7. The swallow-holes of the creek at the bottom of the Shizilu plain are surrounded by a great deal of silt indicating washing underground. The completely altered water regime of the channeled creek adds to this (Photo A. Mihevc). kitkras2.p65 3.12.98,9:39 230 Black 231 2 Andrej Mihevc Land Use in Mountainous Karst Areas Fig. 2.10.8: Corn field on the slope beneath the entrance to Dadong Cavern, Panxian. (Photo A. Mihevc). Fig. 2.10.9. The vicinity of the village of Taishaba. This area is highly settled because of a rela- tively large amount of soil. Fields are cleared of rocks, the rocks are stacked into dry walls and terrace scarps. The scarps are only a few years old, indicating the fight against soil erosion and also the increasing pressure on land (Photo A. Mihevc). kitkras2.p65 3.12.98,9:40 231 Black 232 2 Andrej Mihevc Land Use in Mountainous Karst Areas Fig. 2.10.10. At the bottom of a large depression by the swallow-holes of an intermittent creek, much silt has formed in the karst loam. Heavy erosion is probably the consequence of the altered hydrological characteristics of the upper layer of soil, which is no longer capable of water retention. The runoff is thus rapid and washing into the karst is intense (Photo N. Zupan Hajna). city of Liupanshui. This part of the plateau has an average annual temperature of 11- 19 and receives from 900 to 1500 mm of precipitation. The karst plateau is dissected into nu- merous valleys, oblong depressions and karst plains. Positive relief forms, groups of summits or fengcongs, dominate the land- scape, causing the relief to appear dissected with height differences between the bot- toms of depressions and the summits of up to 300m. The plateau is also crossed by the Beipanjiang river, which has carved a can- yon 600 to 700 m above sea level, thus cre- ating 1700 m in height differences. Despite the relatively poor climatic con- ditions, dissected relief, soil and surface water scarcity, the karst relief is utilized up to the cone summits. Taishaba is a small settlement located by the main road of the dissected relief on the Yezhong plateau around 2300 m above sea level. The flatter parts of the depression between the cone summits are converted into large fields. Inclined slopes are ter- raced, terraces become smaller as the in- cline increases, and are built below an in- cline of 20-30. Above the terraces slopes are dug between rills below an incline of 33-45. Only more steeply inclined slopes are not cultivated, although they are over- grown with bushes and other vegetation which is used for collecting firewood, graz- ing animals or picking edible plants or cat- tle feed. Between the village of Majiachong and the edge of the Beipanjiang river canyon on a high plateau is the dissected karst relief of cone hills and an oblong depression be- tween them. The summits are up to 2300 m above sea level. The bottoms of the de- pressions, large dolines and cockpits are 2100 m above sea level. The inclines of the summit slopes are mostly greater than 45. The relief is structured of thick bedded limestone and in some places limestone with chert. The area is settled in the form of scat- tered farms and some small villages. Large villages exist only on the edge of the pla- teau, near the contact with non-carbonate rock in dry valleys. This settlement is a few centuries old. The settlements continue to expand, new homes are also being built in previously unsettled areas. Water supply is difficult, the water is accumulated in cis- terns dug in the ground or from a few small creeks in surface water collectors. The bottoms of depressions or flatter ar- eas between the summits, primarily where there is chert in limestone, more soil has formed and this can be ploughed. The ter- races are small, in some places only a few meters long and wide. Soil on steeper slopes is turned by hand, on the steepest and shady slopes cattle are grazed or the area is over- kitkras2.p65 3.12.98,9:40 232 Black 233 2 Andrej Mihevc Land Use in Mountainous Karst Areas grown with bushes or trees. There are no longer any old trees. The Beipanjiang river has cut a canyon, up to 1700 m deep, in the Yezhong plateau. The canyon is cut into two levels by a vast structurally-conditioned terrace. In the lower part of the canyon above the river, there are vertical walls up to 500 m high or steep slopes where agricultural land use is practically impossible. Three different kinds of monkey have remained in the area for this reason: Presbytis F.Franciosi, Macaca M. Mulata, and Macaca Thibetana, as well as the wild sheep, Naemorhedus Goral Griseus. Despite the relatively sparse population in the protected area of the natural park of the Beipanjiang river canyon, which ex- tends across 20 km 2 , around 2500 people live there. In the reserve a natural, relatively well-preserved forest grows, the walls are bare. There is a vast shelf, around 2 km wide, with an incline of about 20. The shelf is formed of rock in which layers of lime- stone interchange with layers of coal and marl. A thicker layer of soil has developed Fig. 2.10.11. Yezhong plateau. Accumulation of water in bed of small creek in the side of a large sink-hole (Photo A. Mihevc). Fig. 2.10.12. Yezhong plateau. Large fields can be ploughed using draught cattle. Because of water scarcity, the prevailing plant in the fields is corn (Photo A. Mihevc). kitkras2.p65 3.12.98,9:40 233 Black 234 2 Andrej Mihevc Land Use in Mountainous Karst Areas on this rock and the relief is cultivated in- tensively. The surface has been converted into small terraces and the prevailing crop is corn. Cultivation has caused soil erosion which, judging by the exposed subcutane- ous forms, has removed a layer of soil up to 1 m thick from the whole surface. Rocks have thus reached the surface and were at first broken off, but the erosion has pro- gressed rapidly. Small rain rills cut into the subcutaneous and broken surfaces of rocks indicate the period of the first erosion and the breaking up of the tops of the rock chunks. In the vicinity of the city of Xichou in South Yunnan, the karst plateau is located at an altitude of 15001800 m and cut into it are low valleys and large karst plains with the bottom at a level of around 1300 m. Because of the lower position, the climate is warmer and the area is more densely set- tled than the higher plateaus. The dry sea- son is more pronounced and the difficul- ties concerning water supply are greater. The bottoms of karst valleys have flow- ing submerging rivers, making them appro- priate for irrigation and growing plants that need a large amount of moisture. There is no flowing water on the slopes and on the higher plateau. The water supply is based on water reservoirs dug into the ground and sealed with cement. Flatter slopes are formed into terraces in places where there is some soil. The construction of terraces has not yet been completed and was begun following a government program in the last decade. Steeper or rockier areas are farmed by turning the soil between rills. Other karst land uses with important environmental impacts A strong impact of the degradation of the natural landscape is caused by other tra- ditional or new activities. They are signifi- Fig. 2.10.13. Water reservoir by the village of Miandze, Xichou. The fissures widened by corrosion and filled with loam were used, this is indicated by the subcutaneous forms on the wall. (Photo A. Mihevc) kitkras2.p65 3.12.98,9:40 234 Black 235 2 Andrej Mihevc Land Use in Mountainous Karst Areas Fig. 2.10.14. Charcoal is produced in underground stoves. The furnaces are located where there is enough wood and where the terrain is less rocky (Photo A. Mihevc). Fig. 2.10.15. Pile for producing coke. The escape of gases rich in sulfur oxides is visible. (Photo A. Mihevc) kitkras2.p65 3.12.98,9:40 235 Black 236 2 Andrej Mihevc Land Use in Mountainous Karst Areas cant because of their spatial extent, as we find them even in areas which are difficult to access by transport. Charcoal production is an important complementary activity. Charcoal is used in cooking, heating and forging. It was more common in the past while today it is being replaced by coal and coke. Charcoal is an important product especially in mountain- ous areas where forests are still preserved. Trunks up to 15 cm thick are the most suitable for charcoal production, these are burned in furnaces with a chamber, chim- ney and a side access dug into the ground. During the time of The Great Leap For- ward (at the beginning of the sixties), each village had to produce iron. For this, primi- tive furnaces were built and they used wood charcoal for smelting. This is how the last remains of the forests were ruined. Today the effect of charcoal production is less, al- though it does hinder reforestation as does the use of slash and burn to create grazing land. Charcoal production is today less exten- sive than coke production. Thin layers of black coal often lie between the limestone of the Chinese karst. This is exploited in small mines and burnt in furnaces similar to the ones used for charcoal production to produce coke. Coke is burned primarily close to the roads, thus allowing the pro- duced coke to be distributed by truck to users, ironworks or large settlements where it is used in households. Coke production is a major air polluter as the coal used in the process contains a lot of sulfur. In places where coke is used for a longer period of time, the gases com- pletely destroy the nearby vegetation. An important product of the karst areas is lime. Lime-kilns are established beside the road close to important users (i.e. larger settlements). Coal and coke are most com- monly used for burning, lime is sometimes produced during coke burning. The production of lime also heavily pol- lutes the environment with sulfur dioxide Fig. 2.10.16. Traditional form of lime-kiln. Coke is used for burning (Photo A. Mihevc). kitkras2.p65 3.12.98,9:41 236 Black 237 2 Andrej Mihevc Land Use in Mountainous Karst Areas emissions. Even more noticeable are the many stone-pits which strongly degrade the visual appearance of the landscape. Because stone-pits, lime-kilns and coke furnaces are often located in valleys near roads, this is where the negative effects of these activi- ties are concentrated and they create a spe- cific form of landscape degradation. Conclusion and comparison with Mediterranean karst land use The main limiting factors in land use in the South Chinese karst are scarcity of soil (i.e. rockiness), high degrees of incline, and scarcity of water. Soil is preserved at the bottom of plains, at the bottom of depressions or where lime- stone contains additions of other rock like chert, allowing the soil to form. Soil in de- pressions, especially smaller ones, has to a great extent been washed from the slopes. It is possible to evaluate the degree of ero- sion through history from the expansion of subcutaneous corrosion forms on rocks that now lie exposed. Fields with larger quantities of soil are ploughed. Small fields and plots which are only a few meters long by a few meters wide are also ploughed. Smaller surfaces are cul- tivated by hoeing or with special narrow shovels. In this way even narrow belts of soil between rocks, sometimes as little as 20 cm wide, can be cultivated. The smallest plots can accommodate only one agricul- tural plant for example one cornstalk, one tobacco plant or one hemp plant. In such places the broken tops of rocks are heaped in small stacks or piles. Terraces are less common in karst areas. Most of them situated at the bottom of larger karst depressions, where irrigation is still possible and the dominant crop is rice. Where irrigation is not possible, ter- races are built to sustain cattle farming which is easier and to prevent erosion. Ter- races are built on slopes with an incline of Fig. 2.10.17. New centre of the area, Liupanshui is growing on the edge of large karst polje (Photo A. Mihevc). kitkras2.p65 3.12.98,9:41 237 Black 238 2 30 or less. Steeper slopes are usually so rocky that there is not enough soil on them to build terraces. Inclined terraces are of- ten built on steeper slopes. The terraces are fairly horizontal in the direction of the steepest incline of the slope, but they de- scend to the side with a slighter inclination. In the area of Yunnan the terraces on non-irrigated surfaces with rocky stacked scarps are newer, at the most 20 years old, this implies the increase of the pressure of population on the land and the fight to pre- vent soil erosion. Settlement patterns are various, from ur- ban settlements in karst and large villages to dispersed settlement in small villages. Small villages and individual homes seem to be the newest form of colonization of previously unsettled karst land. They are usually on the edges of depression bottoms dolines or cockpits. Fields for cultivation are at the bottom, slopes where soil is only present in cracks between rills are also cul- tivated. Steeper or rockier slopes are used for grazing pigs or cattle, and sometimes goats or sheep. For this purpose these sur- faces are burnt and thus cleared of bushes. Water is necessary for drinking and also for irrigating agricultural land. Small karst springs have clean potable water and are Andrej Mihevc Land Use in Mountainous Karst Areas often protected. Water from larger sources is used for irrigation. On plains, numerous vertical shafts connecting to groundwater or drilled wells are used for pumping wa- ter. Water is retained on the surface as long as possible. The largest amounts of water are re- quired for rice growing, which is why it this is grown at the bottom of plains where wa- ter is abundant, as are sugar cane and veg- etables. Where irrigation is not possible, corn, hemp tobacco and other plants pre- vail. The comparison of land use in karst ar- eas, primarily of terrace and scarp building, points to some common features of karst in some parts of China and Mediterranean karst. The comparison is interesting be- cause karst in China is agriculturally over- burdened due to hand cultivation, land in- terventions in karst areas are still very new in some places. Intensive land use is being abandoned in the Mediterranean karst, in contrast to China where it has not reached its peak extent or intensity. Understanding agricultural land use and observing the natu- ral processes which are triggered by it can assist in the reconstruction of past processes in karst areas, understanding them in the present and planning suitable future use. kitkras2.p65 3.12.98,9:41 238 Black 239 2 Karstification is controlled under the time and space by physical geographic, geo- logical backgrounds and its developing his- tory, while the differences of karstification and its results are reflected by the karst phenomenon. The development and evolu- tion of karst in China and Slovenia might be contrasted through following aspects. 1. Carbonate formation: Carbonate rocks in Slovenia are mainly shallow water shelf carbonates of the Mesozoic and Paleogene age. An important influence on karst development had Cretaceous to Eocene flysch beds that presently separate different mostly carbonate thrust and ex- tended nappes. In Chinese karst area car- bonate formation were developed from Proterozoic to Mesozoic and are mainly the carbonate rocks of Palaeozoic to Early Mesozoic in stable continental block, which is of very high thickness and with non- carbonate deposit constantly. Modern carbonate mudstones generally have porosity of around 60 to 70 % with very surficial deposits having even higher porosities. Porosity values for grainstones range from 40 to 50 %. These initial poro- sities in both shallow-water carbonate sediments and deep-water chalks with in- creasing age and/or deepening burial depth of the sediments by the compaction and diagenesis and are influenced by the com- positions and texture of rocks. Therefore the original porosity of carbonate forma- tion shows the older geological age, the lower of original porosity generally. In North China, the intercrystal poros- ity of dolomite in Sinian system is less than 1 %. The porosity of Devonian-Carbonifer- 2.11. CONCLUSION - CONTRAST THE KARST OF CHINA WITH SLOVENIA Zhang Shouyue, Andrej Mihevc, Bojan OtoniŁar ous carbonate rocks in Guilin area presents 1,79 % in dolomite and 0,67 - 0,78 % in lime- stone. The effective porosity of Triassic lime- stone in Sichuan are 0,49 - 1,53 % and 0,92 - 8,25 % in dolomite. It is clearly that the karstification is developed more favourable in Mesozoic-Cenozoic by porosity - one of the voids for karst development. 2. The main geological structures and landform features of Slovenia were formed mostly in Cretaceous and Tertiary and they are the products of the last stages of the Al- pine orogeny. All megatectonic units of western Slovenia, where most of the Slovenian karst is developed, belong to the Dinarides and consist of thrust and ex- tended nappes with directions of structural elements W-E in the Southern Alps and In- ner Dinarides, and NW-SE in the Outer Dinarides (Placer,1996). Together with for- mation of the nappe structure flysch depo- sition started since Cretaceous and had been finished till Eocene. Towards south and south-west the carbonate basement is overlain by younger and younger flysch beds, what is an evidence of the migration of the flysch basin in that direction (Pla- cer,1996). Placer (1996) also considers that significant faults that strike NW-SE, SW-NE, W-E and N-S were started during Mesozoik and later often reactivated. Although Gams (1965) considers that the karst morphology in Slovenia is obviously young we should reconsider this statement on the basis of the above presented ascertainments. In the end of Palaeozoic, the Mainland China except the part of Qinghai, Xizang are oceanic crust, most of the area have Zhang Shouyue, Andrej Mihevc, Bojan OtoniŁar Conclusion - Contrast the Karst of China ... kitkras2.p65 3.12.98,9:41 239 Black 240 2 been become as the continental crust. The strong crust movement of Cenozoic be- longs to the landmass change in the plate, presenting mantle fold, rift, magmatic ac- tion and basin structure and so on. There are Yanshan period mantle fold which was developed in Jurassic and Cretaceous all over China, the geological structure of Chi- nese karst area was laid in this period and also the beginning of new period of kar- stification. The mantle fold of Himalayan period was mainly in West China. The mod- ern geomorphic outline of China was set- tled basically beginning from the end of Pliocene and going on for the present neotectonic period. The third episode of Himalayan movement beginning from the end of Pliocene made the rising of West China strongly, and the raising of peneplane and the plane of denudation, and the de- scending of plane formed before Quater- nary in East China, the Quaternary with huge thickness was deposited at the same time. It is quite evident that karstification of East China was undergone a long period since late Cretaceous, while new karsti- fication period in Slovenia was begun from Late Tertiary, but they had been influenced by the raising of earths crust and the dif- ferential movement of block. 3. Climate factor is closely related to karstification, so the karstification under different climate zone is a problem of com- mon interest to be discussed. Slovenia be- longs to the Mediterranean climate zone and a transition area between the climate of Mediterranean and continent. With an annual average precipitation between 1200 and 3500mm, the major part of the Dinaric and the Alpine karst territory receives an- nually above 1500mm. The basic features of the Mediterranean climate is low rainfall in Summer, but most of the Dinaric karst area appears as the transition climate with well-distributed rainfall. According to the data from Ljubljanica river basin, all the rain- fall are between 100 and 130mm for each month, except with rainfall less than 100mm in February, July and August. In Alpine karst area of north part, there are annual average rainfall more than 2000mm and accumulated snow through- out the year, forming relatively large caves which was influenced by the glacier of Qua- ternary. Owing to the comprehensive actions of raising the Qinghai-Xizang plateau strongly and atmosphere circulation, the East Asian monsoon have been strengthened since sev- eral million years. Therefore, the Mainland China has been resulted in the basic fea- tures of monsoon limit, which is less pre- cipitation with dry and cold in winter and much more rainfall with damp and hot in summer. In the tropical and subtropical area of South China, there is humid climate with a aridity less than 1,0, annual average temperature 14 - 24 0 C and annual rainfall 800 - 1600 mm, reaching to 1800 - 2000 mm in part of precipitation centres and increas- ing the temperature and precipitation gradually towards to south. Carbonate rocks area in North China belongs to mid- and warm-temperate zone with dry and sub-humid climate, having the aridity between 1,0 and 1,5, annual average temperature from 6 to 14 C and annual rainfall about 400 - 800 mm The annual rain- fall couldnt be well-distributed due to the feature of East Asian monsoon climate, only part of the precipitation could be fully in- volved in the karstification and another part would flow into the river quickly. For ex- ample, the annual rainfall in East Yunnan and West Guizhou area is some 1100 - 1500 mm, among them, 75 - 85 % are concen- trated in between May and October and occupy frequently 50 % of annual rainfall in between June and August. According to the analysis for carbon di- oxide in soil air, the results measured in dif- ferent karst area of Slovenia in November show that most of the CO 2 content within 50cm under the surface are between 10000 and 25000 ppm, the highest even can be found from 30000 to 64000 ppm, while in China, the CO 2 contents measured from soil air are several thousands in general, the highest result about 18500-24000 ppm only can be found in tropical rainforest. It is clearly that high CO 2 content of soil air in Slovenia is widespread and is bound up with rainfall and its distribution. Zhang Shouyue, Andrej Mihevc, Bojan OtoniŁar Conclusion - Contrast the Karst of China ... kitkras2.p65 3.12.98,9:41 240 Black 241 2 The contrast from climate factor shows that the water run-off is of important sig- nificance as a major factor of karstification and depends to the rainfall and its distribu- tion. The annual rainfall in Slovenia is gen- erally more abundant and well-distributed than in Chinas, it is the great favourable condition to develop modern karstification. 4. The results of karstification display karst landscape and caves. Each karst cycle corresponding to the raising of landmass can be divided into different evolution stages. Under the conditions of similar cli- mate zone, the karst phenomenon are simi- lar for periods of relative stability of land- mass or for periods of strong uplifts. Karst landscapes in Slovenia are gener- ally on stages of the disintegration of posi- tive landform, appearing to deep doline developed on the surface of plateau, unde- veloped surface water system and many caves formed by vertical influent from vadose zone - doline karst. Karst area in China due to many cycles of karstification ever since the Cretaceous and its east part influenced by strong raises of Qinghai-Xizang plateau since the end of Tertiary, some denudation planes of differ- ent period were developed under differen- tial movement of blocks and mainly uplift with different raising scope and the de- nuded surfaces at the same period lower gradually from west to east. So some land- scapes in continuous carbonate rocks dis- tributed area from Yunnan plateau to South China sea can be seen, such as from plateau karst which is mainly positive landform to peaks and dolines or depressions, and karst plane, isolated peak and peak forest which are mainly negative karst morphology. Peak forest on the ocean could be seen in Xialongwan Bay within Vietnam in Beibu- wan Bay. It was found on speleoarchaeological studies in Slovenia that 30 sites of Mid and Upper Palaeolithic belong to Late Pleisto- cene, and no earlier cave archaeological sites could be found. Dating by U-Series from caves, there are several tens samples from 6 caves dated as Mid-Pleistocene. The speleoarchaeological sites in China, there are about 49 sites belong to Late Pleistocene, Mid-Pleistocene from 19 sites and cave fauna sites could also be found in Early Pleistocene and Pliocene. The method of U-series was mainly used to date the speleothems. All the data of dating ages are Mid, Late Pleistocene, thus couldnt be dis- cussed further. Without any Quaternary continent glacial sheet could be found and therefore, the karstification havent been influenced by continental glacial sheet. The main limiting factors in land use on the karst in China and Slovenia are scarcity of soil (i.e. rockiness) and scarcity of water. Soil is preserved at the bottom of plains, at the bottom of depressions or where lime- stone contains additions of other rock like chert, allowing the soil to form. Soil in de- pressions, especially smaller ones, has to a great extent been washed from the slopes. Smaller surfaces are cultivated by hoe- ing or with special narrow shovels. In this way even narrow belts of soil between rocks can be cultivated. Terraces are less common in karst areas of China. Terraces are built on slopes with an incline of 30 or less. In the area the terraces with rocky scarps are newer, indicating the increase of the pressure of population on the land and the fight to prevent soil erosion. The terrace and scarp building started in Mediterranean karst in antiquity. Inten- sive land use is being abandoned in the Mediterranean karst, in contrast to China where it has not reached its peak extent or intensity. In Slovene karst the artificial and natural reforestation returned forest vegeta- tion to more than 50% of the karst areas. The most intensive and dominant proc- esses take place at the bottom of depres- sions, but cones or groups of cones are visu- ally dominant feature in the West Guizhou karst. Cones studied had different topologic positions, dimensions, development and age. Cone relief at 2200 m a.s.l. represents the oldest relief in which the river Bei- panjiang cut a canyon 1500 m deep. The cones in this area are up to 200 m high and the cone slopes are very steep, with incli- nation angles 30 - 50. Cone relief in the middle of the Bei- panjiang river canyon is much younger, Zhang Shouyue, Andrej Mihevc, Bojan OtoniŁar Conclusion - Contrast the Karst of China ... kitkras2.p65 3.12.98,9:41 241 Black 242 2 with cones only about 100 m high. 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