2019 | št.: 62/2 ISSN Tiskana izdaja / Print edition: 0016-7789 Spletna izdaja / Online edition: 1854-620X GEOLOGIJA 62/2 – 2019 GEOLOGIJA 2019 62/2 149-321 Ljubljana GEOLOGIJA ISSN 0016-7789 http://www.geologija-revija.si/userfiles/image/BY.jpg Izdajatelj: Geološki zavod Slovenije, zanj direktor MILOŠ BAVEC Publisher: Geological Survey of Slovenia, represented by Director MILOŠ BAVEC Financirata Javna agencija za raziskovalno dejavnost Republike Slovenije in Geološki zavod Slovenije Financed by the Slovenian Research Agency and the Geological Survey of Slovenia Vsebina številke 62/2 je bila sprejeta na seji Uredniškega odbora, dne 19. 12. 2019. Manuscripts of the Volume 62/2 accepted by Editorial and Scientific Advisory Board on December 19, 2019. Glavna in odgovorna urednica / Editor-in-Chief: MATEJA GOSAR Tehnicna urednica / Technical Editor: BERNARDA BOLE Uredniški odbor / Editorial Board DUNJA ALJINOVIc HARALD LOBITZER Rudarsko-geološki naftni fakultet, Zagreb Geologische Bundesanstalt, Wien MARIA JOĂO BATISTA MILOŠ MILER National Laboratory of Energy and Geology, Lisbona Geološki zavod Slovenije, Ljubljana MILOŠ BAVEC RINALDO NICOLICH Geološki zavod Slovenije, Ljubljana University of Trieste, Dip. di Ingegneria Civile, Italy MIHAEL BRENcIc SIMON PIRC Naravoslovnotehniška fakulteta, Univerza v Ljubljani Naravoslovnotehniška fakulteta, Univerza v Ljubljani GIOVANNI B. CARULLI MIHAEL RIBIcIc Dip. di Sci. Geol., Amb. e Marine, Universitŕ di Trieste Naravoslovnotehniška fakulteta, Univerza v Ljubljani KATICA DROBNE NINA RMAN Znanstvenoraziskovalni center SAZU, Ljubljana Geološki zavod Slovenije, Ljubljana JADRAN FAGANELI MILAN SUDAR Nacionalni inštitut za biologijo, MBP, Piran Faculty of Mining and Geology, Belgrade JANOS HAAS SAŠO ŠTURM Etvös Lorand University, Budapest Institut »Jožef Stefan«, Ljubljana BOGDAN JURKOVŠEK DRAGICA TURNŠEK Geološki zavod Slovenije, Ljubljana Slovenska akademija znanosti in umetnosti, Ljubljana ROMAN KOCH MIRAN VESELIc Institut fr Paläontologie, Universität Erlangen-Nrnberg Fakulteta za gradbeništvo in geodezijo, Univerza v MARKO KOMAC Ljubljani Poslovno svetovanje s.p., Ljubljana Naslov uredništva / Editorial Office: GEOLOGIJA Geološki zavod Slovenije / Geological Survey of Slovenia Dimiceva ulica 14, SI-1000 Ljubljana, Slovenija Tel.: +386 (01) 2809-700, Fax: +386 (01) 2809-753, e-mail: urednik@geologija-revija.si URL: http://www.geologija-revija.si/ GEOLOGIJA izhaja dvakrat letno. / GEOLOGIJA is published two times a year. 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Baze, v katerih je Geologija indeksirana / Indexation bases of Geologija: Scopus, Directory of Open Access Journals, GeoRef, Zoological Record, Geoscience e- Journals, EBSCOhost Cena / Price Posamezni izvod / Single Issue Letna narocnina / Annual Subscription Posameznik / Individual: 15 € Posameznik / Individual: 25 € Institucija / Institutional: 25 € Institucija / Institutional: 40 € Tisk / Printed by: GRAFIKA GRACER d.o.o. Slika na naslovni strani: Flišni ostanki znotraj kraške depresije na južnem delu otoka Krk (foto: E. Šegina). Cover page: Flysch sediments within a depression on karst, the southern part of Krk Island (photo: E. Šegina). VSEBINA – CONENTS Gale, L., Kolar-Jurkovšek, T., Karnicnik, B., Celarc, B., Gorican, Š. & Rožic, B. Triassic deep-water sedimentation in the Bled Basin, eastern Julian Alps, Slovenia ..................... 153 Triasna globljevodna sedimentacija v Blejskem bazenu, vzhodne Julijske Alpe, Slovenija Miler, M., Mašera, T., Zupancic, N. & Jarc, S. Characteristics of minerals in Slovenian marbles ............................................................................. 175 Znacilnosti mineralov v slovenskih marmorjih Mencin Gale, E., Jamšek Rupnik, P., Trajanova, M., Gale, L., Bavec, M., Anselmetti, F. S. & Šmuc, A. Provenance and morphostratigraphy of the Pliocene-Quaternary sediments in the Celje and Drava-Ptuj Basins (eastern Slovenia) ........................................................................................ 189 Provenienca in morfostratigrafija pliocensko-kvartarnih sedimentov v Celjskem in Dravsko-Ptu.jskem bazenu (vzhodna Slovenija) Kanduc, T., Verbovšek, T., Novak, R. & Jacimovic, R. Multielemental composition of some Slovenian coals determined with k0-INAA method and compa.rison with ICP-MS method....................................................................................................................... 219 Multielementna sestava nekaterih slovenskih premogov dolocena s k0-INAA metodo in primerjava z ICP-MS metodo Koren, K. & Janža, M. Risk assessment for open loop geothermal systems, in relation to groundwater chemical composition (Ljubljana pilot area, Slovenia) ....................................................................................... 237 Ocena tveganja za odprte geotermalne sisteme, povezanega s kemicno sestavo podzemne vode (pilotno obmocje Ljubljana, Slovenija) Adrinek, S. & Brencic, M. Statistical analysis of groundwater drought on Dravsko-Ptujsko polje ......................................... 251 Statisticna analiza suše podzemne vode na primeru Dravsko-Ptujskega polja Ocena doseganja trajnostnih ciljev z vidika upravljanja in varovanja podzemnih voda v Sloveniji.................................................................................................................................. 267 Assessment of achieving sustainable goals from the groundwater management and protection perspective in Slovenia Ceru, T. & Gosar, A. Pregled uporabe georadarja na krasu................................................................................................ 279 Application of ground penetrating radar in karst environments: an overview Koroša, A. & Mali, N. Razširjenost pesticidov v vodonosniku Dravskega polja.................................................................. 301 Occurence of pesticides in Dravsko polje aquifer Navodila avtorjem.................................................................................................................................. 320 Instructions for authors .......................................................................................................................... 321 GEOLOGIJA 62/2, 153-173, Ljubljana 2019 © Author(s) 2019. CC Atribution 4.0 License https://doi.org/10.5474/geologija.2019.007 Triassic deep-water sedimentation in the Bled Basin, eastern Julian Alps, Slovenia Triasna globljevodna sedimentacija v Blejskem bazenu, vzhodne Julijske Alpe, Slovenija Luka GALE1,2, Tea KOLAR-JURKOVŠEK2, Barbara KARNICNIK3, Bogomir CELARC2, Špela GORICAN4 & Boštjan ROŽIC1 1Univerza v Ljubljani, Naravoslovnotehniška fakulteta, Oddelek za geologijo, Aškerceva 12, SI-1000 Ljubljana, Slovenia; e-mail: luka.gale@geo-zs.si 2Geološki zavod Slovenije, Dimiceva ulica 14, SI-1000 Ljubljana, Slovenia 3Škalska cesta 9, 3320 Velenje, Slovenija 4ZRC SAZU, Paleontološki inštitut Ivana Rakovca, Novi trg 2, SI-1000 Ljubljana, Slovenia Prejeto / Received 3. 10. 2019; Sprejeto / Accepted 7. 11. 2019; Objavljeno na spletu / Published online 24. 12. 2019 Key words: Upper Triassic, Southern Alps, paleogeography, conodonts, radiolarians Kljucne besede: zgornji trias, Južne Alpe, paleogeografija, konodonti, radiolariji Abstract The Bled Basin was a Middle Triassic–Early Cretaceous basin whose remnants are preserved in the eastern Southern Alps in western Slovenia. The early evolution of the basin is recorded in the Upper Ladinian to Lower Jurassic Zatrnik cherty limestone formation, which in the Pokljuka Nappe overlies Middle Triassic volcanics, volcaniclastics and hemipelagic limestones. The Zatrnik Limestone is poorly documented and biostratigraphically not well constrained. The base of the Zatrnik Limestone was logged in four sections in the eastern part of the Pokljuka plateau. An Upper Ladinian Muelleritortis cochleata Radiolarian Zone was recognised in the lowermost part, whereas conodont data indicate Julian to latest Tuvalian/early Norian age for the rest of the logged sections. Microfacies analysis indicates hemipelagic deposition on a basin plain and/or distal slope, which is often interrupted by distal calciturbidites. Izvlecek Blejski bazen je bil srednjetriasni do zgodnjekredni globljemorski sedimentacijski prostor, katerega ostanki so ohranjeni v Pokljuškem pokrovu vzhodnih Južnih Alp v zahodni Sloveniji. Zgodnji razvoj bazena je zabeležen v srednjetriasnih vulkanitih, vulkanoklastitih in hemipelagicnih apnencih, ki jim sledi zgornjeladinijska do spodnjejurska formacija Zatrniškega apnenca z roženci. Zatrniški apnenec je sedimentološko in biostratigrafsko razmeroma slabo raziskan. V clanku so predstavljeni štirje profili Zatrniškega apnenca z vzhodnega dela Pokljuke, ki zajemajo spodnji del formacije. V najnižjem delu formacije je bila dolocena zgornjeladinijska radiolarijska cona Muelleritortis cochleata, višji deli profilov pa vsebujejo julske, tuvalske in/ali spodnjenorijske konodontne združbe. Mikrofaciesi kažejo na hemipelagicno in turbiditno sedimentacijo na bazenski ravnici in/ ali na distalnem delu pobocja. Introduction This basin is usually referred to as the Sloveni- Stratigraphically continuous successions of an Basin s. str. (Cousin, 1970, 1973; Buser, 1989, Upper Triassic hemipelagic, pelagic and grav-1996) or the Tolmin Basin (Cousin, 1981; Rožic, ity-flow deposits up to several hundred meters 2009) and is relatively well studied (e.g., Rožic et thick preserved in north-western Slovenia tes-al., 2009; Gale, 2010; Gale et al., 2012; Gorican et tify to the existence of at least three long-lived al., 2012; Rožic et al., 2017, with references). The Mesozoic marine basins located near the western second basin has been identified on the basis of margin of the Neotethys Ocean. Continuous suc-Upper Triassic to Lower Jurassic open-marine cessions of Ladinian to Upper Cretaceous deep-facies exposed in the northern Julian Alps (Lieb­er-marine strata are mostly located in the Tolmin erman, 1978; De Zanche et al., 2000; Gianolla et Nappe of the eastern Southern Alps (Buser, 1987). al., 2003; Gale et al., 2015), the Southern Kara­ Fig. 1. Location of the studied area. (a) Geographic position of the area shown in Figure 1b. (b) Simplified tectonic map of NW Slovenia with extent of Upper Triassic deeper-marine deposits divided into distinct basins, as discussed in the pa­ per: Bled Basin (BB), Tarvisio Basin (TaB), and Tolmin Basin (ToB). The map is modified after Placer (1999), Buser (2010), Gale et al. (2015), Gorican et al. (2018). The spatial distribu­tion of basinal deposits is based on the map in Rožic (2016). vanke Mountains (Krystyn et al., 1994; Lein et al., 1995; Schlaf, 1996), and in several outcrops west of this area (Geyer, 1900; Gianolla et al., 1998, 2010; Caggiati, 2014). Gianolla et al. (2010) and Gale et al. (2015) refer to this paleogeograph­ ic unit as the Tarvisio Basin. Finally, the third area with Upper Ladinian to Lower Cretaceous deeper marine successions, paleogeographically belonging to the Bled Basin, extends between the lakes Bohinj and Bled (Fig. 1). The stratigraphic succession of the Bled Basin starts with Upper Anisian – Ladinian carbonate breccias and volcaniclastic rocks deposited on top of massive Anisian dolomite (Buser, 1980). The overlying formation, which constitutes the focus of this paper, is composed of bedded lime­stone with chert some hundreds of meters thick (Cousin, 1981; Buser, 1987; Gorican et al., 2018). This formation was first noted by Diener (1884), Härtel (1920), and Budkovic (1978). Cousin (1981) referred to it as the Zatrnik Limestone. He con­sidered the upper part of the Zatrnik Limestone to be Rhaetian to Early Jurassic in age, while the base of the formation was dubiously placed in the Carnian. The name Zatrnik Limestone was later abandoned and the informal term Poklju­ka Limestone or Pokljuka Formation was more commonly used instead (Dozet & Buser, 2009; Buser, 2010). Fossil bivalves (Buser, 1980) and conodonts (Kolar-Jurkovšek et al., 1983; Ramovš, 1986, 1998), confirmed ages from Late Ladinian to Late Norian, but no continuous sections have Fig. 2. Lithostratigraphy of the Bled Basin (Pokljuka Nappe). The thickness of the Zatrnik Limestone is not yet ful­ly reconstructed. The measured sections indicate roughly 220 m covering Longobardian to Lower Norian. Modified after Gorican et al. (2018). been logged. The recent reambulation of the area stratigraphically places the Zatrnik Limestone between the Upper Anisian to Ladinian volcan­ics and volcaniclastics, and the Pliensbachian carbonate Ribnica Breccia. The succession con­tinues with various pelagic and gravity deposits (see Fig. 2 and Gorican et al., 2018). In this paper we present three detailed sections and one schematic section from the eastern part of the Pokljuka plateau encompassing the lower part of the Zatrnik Limestone. The sedimentolog­ical characteristics of the Zatrnik Limestone are described for the first time in order to identify the depositional environment and the type of sedi­mentation there. Conodonts, radiolarians, benthic foraminifera and microproblematica were deter­mined from residues and thin sections. Geological setting Recent paleogeographic reconstructions place the Bled Basin on the oceanward side of the Ju­lian Carbonate Platform (Fig. 3; Kukoc et al., 2012; Gorican et al., 2018). The sedimentary suc­cession of the Bled Basin is situated today within the Julian Alps that belong to the eastern South­ern Alps (Fig. 4; Placer, 1999). Two episodes of thrusting were recognised in the eastern South­ern Alps: the latest Cretaceous–Eocene NW-SE striking and SW verging thrusts are overlapped by younger (Oligocene?–Miocene) E-W striking, S-verging thrusts (Doglioni & Siorpaes, 1990; Poli & Zanferarri, 1995; Placer & Car, 1998). Gorican et al. (2018) called all nappes of the eastern Ju­lian Alps the Julian Nappes. From the bottom to the top these comprise the Krn Nappe, the Slatna Klippe and the Pokljuka Nappe (Fig. 5). Prima­ry thrust contacts are only preserved around the Slatna Klippe. Elsewhere, they were cut and dis­placed along NE-SW and NW-SE striking faults. Both, the Krn Nappe and the Pokljuka Nappe in Fig. 4. Position of the studi­ed area (star) on a regional tectonic map. Modified after Kovács et al. (2011). Fig. 5. Structure of the Julian Alps. (a) Schematic structural map of the Julian Alps. Abbrevations: SK – Slatna Klippe, PN – Pokljuka Nappe, TN – Tolmin Nappe, kk – Krn-Kobla Thrust, rvc – Resia-Val Coritenza Backthrust, sat – South Alpine Thrust. Simplified after Gale et al. (2015) and Gorican et al. (2018). (b) Superposition of the Julian Nappes and their simplified lithostratigraphy. the lower part consist of Anisian shallow marine carbonates and Upper Anisian–Ladinian pelagic limestone and volcaniclastics. In the Krn Nappe and the Slatna Klippe these are followed by mas­sive Carnian limestone and dolomite, while in the Pokljuka Nappe the succession continues with the deeper-marine Zatrnik Limestone (Gorican et al., 2018, with references). Towards the south, the Julian Nappes are in thrust or steep reverse-fault contact with the Tolmin Nappe, preserving suc­ cessions of the Tolmin Basin (Placer, 1999). The investigated sections within the Zatrnik Lime­stone were logged in relatively tectonically un­disturbed blocks of the Pokljuka Nappe with gently to moderately steep dipping strata, gener­ ally in the W and NW directions. Material and methods The lowermost part of the Zatrnik Limestone was logged in four sections (Fig. 6). Microfacies analysis is based on 174 thin sections 47×28 mm in size. Thin sections were studied in transmit­ted light with an optical microscope. Dunham’s (1962) classification was used for the description of textures. Point-counting was performed on microphotographs taken from selected thin sec­tions. We counted 300 points on a random grid using JMicroVision v1.2.7 (Copyright 2002-2008 Nicolas Roduit) software. Composite conodont samples were taken over intervals of 1.5 to 10 m, depending on the uniformity of the lithology. Car­bonate rock samples were treated in acetic acid (cca. 8 %) followed by heavy liquid separation. The recovered faunas are kept in the micropal­eontological collection at the Geological Survey of Slovenia (samples GeoZS 5793-5798, 5924­5928, 6001-6019). The SEM photos of conodont specimens were taken at the GeoZS (JEOL JSM Fig. 6. Geographic position of the studied sections. The numbers indicate sections: Zatrnik (1), Blejski vint-gar (2), Galetovec (3), and Poljane (4). Distribution of the basinal formations is drawn after Buser (2009), and Gorican et al. (2018). 6490LV Scanning Electron Microscope). Cono­dont biostratigraphy follows Rigo et al. (2018), and Kolar-Jurkovšek and Jurkovšek (2019). It should be noted, however, that Chen et al. (2015) have a slightly different view on the species and their ranges, so that stratigraphic boundaries could also be assigned somewhat differently. At the Zatrnik location, two radiolarian samples were taken after radiolarians were detected in the field with a hand lens. These samples were processed in the same manner as the conodont samples. The illustrated radiolarian specimens are stored at ZRC SAZU, Ljubljana (samples RA 5843, RA 5844). Fig. 7. Field view of the Zatrnik Limestone. (a) Medium-thick bedded mudstone with chert nodules, characterizing the upper (Norian and Rhaetian?) part of the formation. (b) Zatrnik Limestone at the top of the Zatrnik section, Carnian. (c) View of the Blejski vintgar gorge with exposures of the Carnian part of the formation. (d) Thin-bedded calcarenites (packstone, grain-stone) in the Blejski vintgar section. (e) Slump and scour structures in the Blejski vintgar section. (f) Transition from bedded limestone with chert into seemingly massive limestone in the Poljane section. Description of sections In the lower part the Zatrnik Limestone is represented by thin- and medium-bedded cherty micritic limestone and calcarenites. Me-dium-thick bedded micritic limestone with chert nodules is the dominant lithofacies in the upper part of the formation (Fig. 7). The logged sections comprise only the lower, Upper Ladinian to Low­er Norian part of the formation (Fig. 8), as a good exposure of the Norian and Rhaetian part of the formation has yet to be found. A detailed descrip­tion of microfacies (MF) types from the logged sections (Figs. 9–12) is given in Table 1 and which are illustrated in Figures 13–14, whereas the de­termined fossils are listed in Table 2 and illus­trated in Figures 15–17. The Zatrnik section (bottom: 46°21’47’’N, 14°2’25’’E; top: 46°21’56’’N, 14°2’26’’ E) is strati-graphically the lowest of the logged sections. Fragments of volcanics and tuff are found in the scree, approximately 10–15 m below the sec­tion. Platy to medium-bedded loose bioclastic wackestone (MF 2 in Table 1) predominates (Fig. 9); this limestone may be silicified and locally has small chert nodules. Thin layers of dark brown marlstone intercalate with limestone in the low­er 3 m of the formation. Radiolarian fauna (Fig. 16) from two samples of radiolarian packstone (MF 3), taken in this part of the section, indicates Upper Ladinian Muelleritortis cochleata Zone (Kozur & Mostler, 1994, 1996). Marlstone is ab­sent in the section higher up. Filament-radiolar­ian-peloidal packstone (MF 8; Fig. 13c) sporadi­cally intercalates with loose wackestone. Parallel lamination is rarely present. Moving upwards, the proportion of packstone gradually increases. Slumping and amalgamations are locally visible. Conodonts Gladigondolella malayensis Nogami, Budurovignathus cf. diebeli (Kozur & Mock), B. mostleri (Kozur) and Paragondolella praelindae Kozur suggest that beds above the radiolarian fauna and up to the 24th meter of the section are (middle-late) Julian in age. Between the 26th and 46th meter, the conodont assemblage compris­es P. praelindae, Quadralella polygnathiformis (Budurov & Stefanov) and rare Q. aff. noah (Hayashi), indicating early-middle Tuvalian age (Rigo et al., 2018; Kolar-Jurkovšek & Jurkovšek, 2019). From the 57th meter up, peloidal packstone (MF 4), peloidal grainstone (MF 9), pebbly intra-clastic grainstone (MF 10), bioclastic-intraclastic floatstone (MF 12), and closely-fitted intraclastic rudstone (MF 13) also occur among microfacies types. Normal grading is present in some beds. Approximately 60 m from the base of the section, P. praelindae is accompanied by Paragondolella inclinata (Kovacs), and later by Paragondolella tadpole (Hayashi). The association indicates late Julian to early Tuvalian age. When we also take into consideration the low number of specimens, which makes determination of assemblages dif­ficult, we suggest the sequence between 11th and 24th m of the section is (undivided) Julian in age, while the upper part of the section is early Tu­valian. Fig. 8. Schematic position of the logged sections as indicated by biostratigraphic data. The position of the Poljane section is uncertain due to negative conodont samples. The Blejski vintgar section (bottom: 46°23’49’’N, 14°5’19’’E; top: 46°23’54’’N, 14°5’24’’E) was logged in shorter subsections and separated by minor faults (Fig. 10). In contrast to the Za­trnik section, this part of the formation is domi­nated by pebbly intraclastic grainstone (MF 10). Peloidal grainstone (MF 9) and peloidal-intra­clastic packstone (MF 7) are also common, while other microfacies types (MF 2 - loose bioclastic wackestone, MF 4 - peloidal packstone, MF 5 -bioclastic wackestone to packstone, MF 6 - dense mollusc wackestone, MF 8 – filament-radiolari­an-peloidal packstone) are subordinate. Scour structures, normal and inverse grading are often observed in micritic limestone, but rarely parallel Fig. 9. Sedimentary log of the Zatrnik section with ranges of conodont species. Microfacies types (see Table 1) are indica­ted on the right side of the logs. types (see Table 1) are indicated on the right side of the logs. lamination and amalgamation. Slumps up to ap­prox. 6 m thick are common. Conodont samples from the lower 12 m of the subsection A were neg­ative. Paragondolella foliata Budurov was recov­ered from the upper 2 m. Subsection B comprises Paragondolella foliata Budurov, Q. polygnathi­formis, G. malayensis and G. tethydis (Julian). Subsection D contains Q. polygnathiformis and Q. aff. noah, suggesting early Tuvalian age. At Mt. Galetovec (bottom: 46°19’38’’N, 14°2’28’’E, top: 46°19’36’’N, 14°2’23’’E), the section was measured schematically along the sides of a vertical wall. Micritic limestone with chert nod­ules predominates (Fig. 11), and the beds tend to thicken towards the top. Amalgamation is com­monly present, and some massive beds probably represent slumps. Quadralella tuvalica (Mazza & Rigo) was found at the base of the cliff wall, indicating early to middle Tuvalian age (Rigo et al., 2018). In the samples from higher up in the section Epigondolella quadrata Orchard, Epigon­dolella rigoi Noyan & Kozur and Epigondolella vialovi (Buryi) were collected. The stratigraphic range of all three species originates from the late Tuvalian to the Lacian (Rigo et al., 2018). The up­per part of the section also contains some beds of pebbly intraclastic grainstone (MF 10), but in contrast to the same MF type in the Zatrnik and Blejski vintgar sections, the amount of micro-bialites, microbial-sponge boundstone clasts and microproblematica is clearly lower on account of mollusc fragments. The difference in foraminife­ral assemblages is also very obvious: whereas fo­raminifera are rare, but diverse in the two strati-graphically lower sections, samples from the top of the Mt.Galetovec section commonly contain in-volutinids Aulotortus sinuosus Weynschenk and Parvalamella friedli (Kristan-Tollmann), which can be present in relative abundance. The fourth section was logged at Poljane (46°23’46’’N, 14°4›32››E; Fig. 12). Medium, and rarely thick beds of micritic limestone (MF 2 – loose bioclastic wackestone) and fine-grained bioclastic wackestone to packstone (MF 5) are present in the lower part of the section. Amal­gamation and chert nodules are locally present. Just as at the top of the Mt. Galetovec section, skeletal carbonate is relatively abundant, and the foraminiferal assemblage is dominated by aulotortids. Thus, we presume these beds are late Tuvalian or younger in age. The section ends at the foot of the massive limestone unit, which is several tens of meters thick. Indistinct, slightly curved and sloping bedding planes can be seen in the lowermost part of this massive limestone (see Fig. 7f), texturally a bioclastic wackestone to mostly known from the Norian to Rhaetian (e.g., packstone (MF 5) and a dense mollusc wackestone Flgel, 1967; Matzner, 1986; Kristan-Tollmann, (MF 6). Foraminifera Alpinophragmium perfora-1990; Gale et al., 2012). tum Flgel was found in this part. This species is Table 1. Description of microfacies types of the Zatrnik Limestone. Facies Microfacies (MF) Description Figures marlstone marlstone (MF 1) Dark brown marlstone is finely laminated and partly silicified. It is present only in the lowermost part of the 13a Zatrnik section in beds up to 15cm thick that interchange with limestone. Lamination is caused by different amounts of organic matter (as opaque bands), orientation of elongated particles and small differences in grain size. Besides very fine-grained matrix, there are a few grains large enough to be identified in thin sections: angular quartz grains and chlorite, small peloids and micritic intraclasts (the largest 0.65 mm in diameter), ostracod shells, echinoderm plates, thin-shelled bivalves and radiolarians. micritic loose bioclastic limestone wackestone (MF 2) Due to variations in clast composition, at least three subtypes were recognised. All have a high amount 13b-d of matrix in common (77–84%). In subtype MF 2A, 6% of the matrix has been washed away. Clasts comprise peloids (12%), sparitic fragments (3%) and echinoderm plates (1.5%). Nodosariid foraminifers and radiolarians are very rare. In subtype MF 2B, peloids represent 5.5% of the area; more common are filaments (4.5%), and possible radiolarians (2%), whereas sparitic fragments and undetermined bioclasts occupy 1% of the area, and microproblematica (Plexoramea gracilis), foraminifers and echinoderm plates each 0.5%. In MF 2C, there are no vugs and very few peloids. Clasts are sparitic fragments (5.5–12%), echinoderms (2.5–6%), and filaments (3.5–5%). radiolarian Radiolarians are in rock-forming abundance, packed closely together. Very rare are thin-shelled bivalves 13e packstone (“filaments”). Radiolarian tests are filled with calcite or are silicified. (MF 3) peloidal packstoneSediment was bioturbated or deposited in laminae 1cm thick. Average grain size is between 0.06 and 13f (MF 4) 0.07mm, with the largest grains 0.17mm in size. Sediment is thus well to very well sorted. Peloids represent around 44% of the area. Far more rare are fragmented bioclasts replaced by spar (up to 3.5%), thin-shelled bivalves (3%), echinoderms, foraminifers (Agathammina austroalpina, Earlandia gracilis, ?Hoyenella sp., Turriglomina mesotriassica, nodosariid lagenida), and microproblematica (Ladinella porata, Thaumatoporella parvovesiculifera, Tubiphytes-like form). bioclastic wackestone to packstone(MF 5) Micritic matrix represents 40–61% of the area; up to 4.5% of the surface consists of irregular vugs filled 13g with drusy-mosaic spar, possibly representing areas where micrite had been washed away. The composition of clasts is variable, but a few types dominate: peloids (7–15% of area), micritic intraclasts (up to 17%; radiolarians were recognised in one), sparitic fragments (3.5–15%), echinoderm plates (1–15%) and thin-shelled bivalves (up to 16%). Foraminifers (Duotaxis, sessile forms, and small nodosariid and miliolid species), spicules and ostracods are very rare. One sample contains larger pieces of brachiopod shells. dense mollusc Grains represent 42% of the area, and on average measure 0.18mm in size. Grains are well sorted. Angular 13h wackestone sparitic fragments predominate (21% of the area). Other grains are angular micritic intraclasts (6%), (MF 6) foraminifers, echinoderm plates, ostracods and thin-shelled bivalves. calcarenite peloidal-intraclasticpackstone(MF 7) In most samples, intergranular space is filled with micritic matrix. In fewer samples, most of the mud has 14a been washed away and the space filled by calcitic cement. Grains represent more than 50% of the thin section area. Average grain size is from 0.1 to 0.2mm, with the largest grains up to 2mm. Sorting ranges from moderately to well sorted. The majority of grains are peloids and dark intraclasts, together representing from 20 to 55% of the thin section area. The latter may be mud chips or fragments of microbialites (distinction is rarely possible at smaller magnifications). Other grains are mostly microproblematica (2.5–4.5 %), echinoderm plates (3–8%), locally thin-shelled bivalves (up to 11%), very rare nodosariid foraminifers and brachiopods. Differentiation from MF 4 is by virtue of smaller grain size and better sorting of the latter. Dolomitization is locally present. filament-radiolarian-peloidal packstone(MF 8) Sediment may be laminated, with laminae differing in grain size, density and percentage of thin-shelled 14b bivalves (these are oriented parallel to laminae) and radiolarians. Alternatively, it is bioturbated. Grains represent 65–70% of the area. Peloids measure 0.07–0.09mm (largest up to 0.24mm), while radiolarians measure 0.18–0.20mm in size. Intraclasts, although rare, are the largest grains with diameters of up to 6mm. Peloids are thus very well sorted. The upper-size limit is represented by light echinoderm plates and flat thin-shelled bivalves. The most common grains are peloids (26–37%), thin-shelled bivalves (9.5–34%), radiolarians (2.5–25%) and echinoderms (3.5–7.5%). Intraclasts represent 0.5–1% of the area, while foraminifers, sparitic clasts, ostracods, fragments of brachiopods, microproblematica and possible dasycladacean algae are very rare. Intergranular space is filled with micritic matrix, locally recrystallized into pseudosparite. Larger calcite crystals fill the space beneath bivalves. Echinoderm plates are overgrown by syntaxial calcite cement. peloidal grainstoneSediment is locally horizontally laminated (laminae differ in grain size, or exchange with laminae of 14c (MF 9) other MF type). Grains represent approximately 70% of the area; intergranular space is filled by granular or drusy-mosaic calcite spar. Grains on average measure 0.15 mm, while the largest reach 0.83 mm in size. Sediment is moderately well to well sorted. Peloids are the predominating grain type (50–60%). Also present are sparitic fragments (6.5–9%), echinoderm plates (1.5–2.5%), microproblematica (up to 4.5%). Foraminifera, gastropods, calcimicrobes and brachiopod fragments are very rare. Echinoderm plates are overgrown by syntaxial calcite. Dolomitization is locally present; dolomite crystals are euhedral, overgrowing peloids or crosscutting older cement and grains. pebbly intraclastic grainstone(MF 10) Grading is commonly present. The largest clasts measure up to 1 cm in size, while average grain size 14d-e is 0.3 to 0.5mm (size changes with grading). Grains are angular and in point contacts. They comprise between 45–75% of the area (on average 67%). The most common grains are intraclasts (49.5%). Microproblematica is more common in Ladinian and Carnian samples (7.5% compared to 0.5% in the Norian samples; note that this is a very conservative estimate, as point counting was performed mainly at small magnifications, which often do not allow for differentiation from micritic intraclasts). Sparitic fragments (5.9%), echinoderms (3.4%), and foraminifers (1%) appear in approximately the same abundance, irrespective of the samples’ age. pebbly intraclastic grainstone(MF 10) Within the lower – middle Carnian part of the succession, intraclasts comprise pelletal packstone 14d-e with Bacinella floriformis, peloidal packstone, bioclastic-peloidal packstone, bioclastic wackestone, calcimicrobes (types Garwoodia and Cayeuxia), microproblematica-sponge boundstone, microbialite (stromatolite, pelletal leiolite), Bacinella-like boundstone clasts and cementstone. Other clasts are peloids (small intraclasts), sparitic fragments, microproblematica, echinoderm plates, foraminifers, radial spherulites, brachiopods, rare green algae, agglutinated worm tubes, bryozoan and ammonite fragments, gastropods and ostracods. In the upper Carnian – lower Norian samples, mudstone, mudstone with filaments and spicules andcalcimicrobes are present among intraclasts, whereas smaller grains contain peloids (small micriticintraclasts), echinoderms, foraminifers, spherulites, sparitic fragments (cortoids), agglutinated wormtubes, and brachiopod fragments. Besides fewer (or even the absence of) microbialites, microbial-spongeboundstones and microproblematica, Carnian and Norian samples differ notably in foraminiferal assemblage.Cement is represented by drusy mosaic calcite. Fibrous rim cement occurs locally. In some samples, coarseeuhedral dolomite fills the intergranular space. Only one example of silicified valves was found. intraclastic-mollusc packstone (MF 11) Grains representapproximately 70% of the area. The intergranular space is filled with micritic matrix (27 % 14f of the area) and drusy mosaic calcite cement (4%). Grains are mostly in point contacts. Sorting is medium to poor, with the average size of grains around 0.35mm and the largest grains measuring 2mm in size. The most abundant grains are sparitic fragments (31% of the area). Most are probably mollusc fragments, but some may belong also to recrystallized involutinid foraminifers. Intraclasts (bioclastic wackestone and packstone) occupy another 23% of the area. Other grains are echinoderm plates (11.5%), foraminifers (3 %), small fragments of Thaumatoporella thalli, and ostracods. Some grains are selectively silicified. fine-bioclastic-grained intraclastic breccia floatstone (MF 12) Micritic matrix represents 46% of the area, whereas clasts occupy the rest of the space. Clasts are poorly 14g sorted, up to 4.5mm large. Among them, intraclasts are the most common (23% of area). They are variable, mostly angular, comprising bioclastic-peloidal wackestone, cementstone, mudstone (or structureless microbialite), stromatolite, microproblematica boundstone, and Bacanella boundstone. Other clasts include fragments of bivalves, oncoids, microproblematica (Tubiphytes, Plexoramea, Ladinella), Dendronella algae, sponges, echinoderm plates, foraminifers, solitary corals, gastropods and ostracods. Bivalve shells are micritized at the margins. Aragonite is replaced by drusy mosaic calcite. closely-fitted One sample comprises closely fitted angular intraclasts (pelletal packstone, fine-grained dense bioclastic-14h intraclastic pelletal wackestone, undetermined silicified clasts, bioclastic-intraclastic wackestone). Rare echinoid spines rudstone also occur. The matrix between clasts seems to be micritic. Bioclastic-intraclastic grainstone is locally (MF 13) visible among clasts, and may be infiltrated into rudstone. Table 2. List of determined fossils. Distribution of conodont taxa (from composite samples) is shown next to sedimentary logs in Figures 9–11. See Figure 9 for position of the radiolarian samples. Fossil group Taxa Conodonts Budurovignathus cf. B. diebeli (Kozur & Mock)vel mostleri (Kozur), Epigondolella quadrata Orchard, E. rigoi Noyan & Kozur, E. vialovi (Buryi), Gladigondolella tethydis (Huckriede), G. malayensis Nogami, Paragondolella praelindae Kozur, P. foliata Budurov, P. inclinata (Kovacs), P. aff. tadpole (Hayashi), Quadralella polygnathiformis (Budurov & Stefanov), Q. noah (Hayashi), Q. tuvalica (Mazza & Rigo) (for distribution of taxa see Figs. 9-12) Radiolarians Sample 5843 (Zatrnik): Acanthotetrapaurinella variabilis Kozur & Mostler, Annulotriassocampe cf. eoladinica Kozur & Mostler, Archaeocenosphaera sp., Dumitricasphaera trialata Tekin & Mostler, Karnospongella bispinosa Kozur & Mostler, Muelleritortis cochleata (Nakaseko & Nishimura), M. expansa Kozur & Mostler, M.s aff. expansa Kozur & Mostler, M. longispinosa Kozur, M. tumidospina Kozur, Paurinella triangularis Kozur & Mostler, Pseudostylosphaera nazarovi (Kozur & Mostler), Ropanaella sp., Scutispongus latus Kozur & Mostler, Spinotriassocampe longobardica Kozur & Mostler, Spongoserrula rarauana Dumitrica, Spongotortilispinus tortilis Kozur & Mostler, Triassocampe? sp., Tritortis dispiralis (Bragin) Sample 5844 (Zatrnik): Acanthotetrapaurinella variabilis Kozur & Mostler, Archaeocenosphaera sp., Dumitricasphaera trialata Tekin & Mostler, Muelleritortis cochleata (Nakaseko & Nishimura), M. expansa Kozur & Mostler, Paurinella triangularis Kozur & Mostler, Pseudostylosphaera nazarovi (Kozur & Mostler), Ropanaella sp., Scutispongus latus Kozur & Mostler, Spongoserrula rarauana Dumitrica, Spongotortilispinus slovenicus (Kolar-Jurkovšek), Steigerispongus cristagalli (Dumitrica), Triassocampe? sp., Tritortis dispiralis (Bragin) Foraminifera Carnian (Zatrnik and Blejski vintgar sections, lower part of Galetovec sections): Glomospirella cf. pokornyi (Salaj), Reophax rudis Kristan-Tollmann, Ammobaculites sp., Gaudyina sp., Paleolituonella meridionalis (Luperto), Earlandia amplimuralis (Pantic), Earlandia tintinniformis (Mišik), Agathammina austroalpina Kristan-Tollmann & Tollmann, Arenovidalina/Ophthalmidium sp., Gsollbergella spiroloculiformis (Oravecz-Scheffer), Turriglomina mesotriasica (Koehn-Zaninetti), Hydrania dulloi Senowbari-Daryan, Piallina bronnimanni Martini et al., Cucurbita longicollum Senowbari-Daryan, C. infundibuliforme Jablonský, C. cf. minima Senowbari-Daryan, Trocholina turris Frentzen, Trocholina sp., Duostominidae, Koskinobullina socialis Cherchi & Schroeder, Pseudonodosaria cf. obconica (Reuss), Austrocolomia sp., nodosariid Lagenida Upper Tuvalian - Lower Norian (middle and upper part of the Galetovec section, Poljane section): Pilammina sulawesiana Martini et al., Reophax rudis Kristan-Tollmann, Ammobaculites sp., “Trochammina” almtalensis Koehn-Zaninetti, Duotaxis sp., “Tetrataxis” humilis Kristan, Alpinophragmium perforatum Flügel, Endothyracea, Planiinvoluta sp., Agathammina austroalpina Kristan-Tollmann & Tollmann, Miliolechina stellata Zaninetti et al., Aulotortus sinuosus Weynschenk, Parvalamella friedli (Kristan-Tollmann), Duostominidae, Variostoma cochlea Kristan-Tollmann, Lenticulina sp., Pseudonodosaria sp., nodosariid Lagenida Microproblematica Carnian (Zatrnik and Blejski vintgar sections, lower part of Galetovec sections): Tubiphytes group (?Tubiphytes obscurus Maslov), Plexoramea cerebriformis Mello, Ladinella porata Ott, Baccanella floriformis Pantic, Plexoramea gracilis (Schäfer & Senowbari-Daryan), Bacinella irregularis Radoicic, Radiomura cautica Senowbari-Daryan & Schäfer Upper Tuvalian - Lower Norian (middle and upper part of the Galetovec section, Poljane section): Thaumatoporella sp., ?Plexoramea cerebriformis Mello, Baccanella floriformis Pantic (g) Bioclastic wackestone to packstone (MF 5). Note foraminifera Duotaxis sp. (arrowhead). Section Poljane; 1.2 meters (h) Dense mollusc wackestone (MF 6). Section Poljane; 6.5 meters. Fig. 14. Microfacies of the Zatrnik Limestone. (a) Peloidal-intraclastic packstone (MF 7). Section Blejski vintgar; subsection B; 1st meter. (b) Filament-radiolarian-peloidal packstone (MF 8). Section Zatrnik; 69.5 meters. (c) Peloidal grainstone (MF 9). Section Blejski vintgar, subsection D; 16.5 meters. (d) Pebbly intraclastic grainstone (MF 10). Arrowheads point at the mar­gin of the microbialite boundstone. Section Blejski vintgar, subsection A; 10.5 meters. (e) Pebbly intraclastic grainstone (MF 10). Sample 1177. (f) Intraclastic-mollusc packstone (MF 11). Section Galetovec; 110th meter. Letter “A” denotes foraminifera Parvalamella friedli (Kristan-Tollmann). (g) Bioclastic-intraclastic floatstone (MF 12). Letter “T” denotes Tubiphytes-like clast, letter “P” a Plexoramea, and white arrowhead a small foraminifera Reophax sp. Section Zatrnik; 58.5 meters. (h) Closely-fitted intraclastic rudstone (MF 13). Section Zatrnik; 58th meter. Fig. 15. Conodonts from Late Ladinian to Norian part of the Zatrnik Limestone. 1. Paragondolella foliata Budurov – immatu­re specimens with very wide basal cavity. Sample GeoZS 5793; Blejski vintgar; Julian. 2. Paragondolella inclinata (Kovacs). Sample HV 6006-2; Zatrnik; Julian. 3. Paragondolella tadpole (Hayashi). Sample HV 6006-1; Zatrnik; Julian. 4. Paragondolella praelindae Kozur. Sample ZA 6017-2; Zatrnik; Julian. 5. Quadralella polygnathiformis (Budurov and Stefanov). Sample ZA 6018-1; Zatrnik; Julian. 6. Quadralella polygnathiformis (Budurov and Stefanov) – with rounded posterior and rounded keel. Sample GeoZS 5796; Blejski vintgar; Julian. 7. Quadralella tuvalica (Mazza and Rigo) – primitive form with weak nodes. Sample GA 5928-1; Galetovec; Tuvalian. 8. Epigondolella cf. quadrata Orchard. Sample GA 5927-1; Galetovec; Tuvalian-Lacian. 9. Epigondolella rigoi Noyan and Kozur. Sample GA 5924-6; Galetovec; Tuvalian-Lacian. Fig. 16. Late Ladinian radiolarians from locality Zatrnik. 1–3. Scutispongus latus Kozur and Mostler. 4, 6. Spongoserrula rarauana Dumitrica. 5. Steigerispongus cristagalli (Dumitrica). 7. Ropanaella sp. 8. Karnospongella bispinosa Kozur and Mostler. 9–10. Paurinella triangularis Kozur and Mostler. 11. Acanthotetrapaurinella variabilis Kozur and Mostler. 12. Spongotortilispinus slovenicus (Kolar-Jurkovšek). 13. Dumitricasphaera trialata Tekin and Mostler. 14. Spongotortilispinus tortilis Kozur and Mostler. 15–16. Archaeocenosphaera sp. 17–18. Tritortis dispiralis (Bragin). 19–20. Pseudostylosphaera na­zarovi (Kozur and Mostler). 21–25, 29. Muelleritortis expansa Kozur and Mostler. 26–27. Muelleritortis tumidospina Kozur. 28. Muelleritortis aff. expansa Kozur and Mostler. This species differs from typical M. expansa by having pyramidal (not blunt) spine tips on the three torsioned spines and by the fourth spine being slightly longer than the other three. It is also close to Muelleritortis koeveskalensis Kozur but typical M. koeveskalensis (see the holotype in Kozur, 1988) has sinistrally torsioned spines. 30. Muelleritortis longispinosa Kozur. 31–32. Muelleritortis cochleata (Nakaseko and Nishimura). 33. Triassocampe? sp. 34. Annulotriassocampe cf. eoladinica Kozur and Mostler. 35. Spinotriassocampe longobardica Kozur and Mostler. Sample RA 5843: figs. 2–3, 7–8, 10–11, 13–17, 19, 22–23, 25–31, 33–35. Sample RA 5844: figs. 1, 4–6, 9, 12, 18, 20–21, 24, 32. Length of scale bar 100 µm for figs. 8–11 and 33–35; 150 µm for figs. 1–6, 13–18 and 21–32; 200 µm for figs. 7, 12, 19–20. Fig. 17 Fig. 17. Sponges and various microfossils from the Carnian and Norian part of the Zatrnik Limestone. (a-c) Undetermined “sphinctozoan” sponges; section Blejski vintgar. (a) Julian. (b-c) Lower Tuvalian. (d) Baccanella floriformis Pantic; section Blejski vintgar; lower Tuvalian. (e-f) Ladinella porata Ott; section Blejski vintgar; Julian. (g) ?Tubiphytes obscurus Maslov (white arrowhead) and Plexoramea cerebriformis Mello (black arrowhead); section Blejski vintgar; Julian. (h) Plexoramea gra­cilis (Schäfer and Senowbari-Daryan); section Blejski vintgar; lower Tuvalian. (i) Thaumatoporella sp.; section Poljane; upper Tuvalian? - Lower Norian. (j-k) Radiomura cautica Senowbari-Daryan and Schäfer; section Blejski vintgar; lower Tuvalian. (j) Transverse section. (k) Longitudinal section. (l) Red algae?; section Blejski vintgar; lower Tuvalian. (m) Calcimicrobe?; section Blejski vintgar; lower Tuvalian. (n) Agglutinated worm tube; section Blejski vintgar; Carnian. (o) Agglutinated worm tube (Terebella sp.); section Blejski vintgar; lower Tuvalian. (p) Bacinella irregularis Radoicic; section Blejski vintgar; Carnian. (q) Dendronella articulata Moussavian and Senowbari-Daryan; section Blejski vintgar; Carnian. (r) Piallina bronni­manni Martini et al.; section Blejski vintgar; Julian. (s) Hydrania dulloi Senowbari-Daryan; section Blejski vintgar; Carnian. (t) Koskinobullina socialis Cherchi and Schroeder; section Blejski vintgar; lower Tuvalian. (u-v) Cucurbita infundibulifor-me Jablonský. (u) Section Blejski vintgar; lower Tuvalian. (v) Section Zatrnik; lower Tuvalian. (w) Cucurbita longicollum Senowbari-Daryan; section Zatrnik; lower Tuvalian. (x) Cucurbita cf. minima Senowbari-Daryan; section Blejski vintgar; lower Tuvalian. (y) Turriglomina mesotriasica (Koehn-Zaninetti); section Zatrnik; lower Tuvalian. (z) Alpinophragmium perforatum Flgel; section Poljane; lower to middle Tuvalian. Discussion Conodont and radiolarian data obtained in this study confirm the Longobardian age of the base of the Zatrnik Limestone. The logged suc­cession reaches up to the Lower Norian, but basi­nal sedimentation clearly continued (cf. Cousin, 1981; Gorican et al., 2018). Micritic limestone with thin-shelled bivalves and radiolarians (e.g., MF 2, 3), dominating in the Zatrnik, Mt. Galetovec and Poljane sections, indicates hemipelagic sed­imentation in an open marine environment. Re-sedimented carbonates are subordinate in these sections, but predominate in the Blejski vintgar section. Normal grading and parallel lamination suggest deposition via turbidites. Sparite-domi­nated varieties (MF 9, 10) are proximal turbidi­tes, whereas micrite-rich microfacies types (MF 2, 4-7, 8, 11) are interpreted as distal turbidites (see Maurer et al., 2003). Mud-supported bioclas-tic-intraclastic floatstone (MF 12) and intraclas-tic rudstone (MF 13) might be debris-flow de­posits (Mullins & Cook, 1986; Eberli, 1991). The predomination of calcarenite in the Blejski vint-gar section suggests deposition in a more proxi­mal part of the basin. Slump structures are also more common in the Blejski vintgar section. The observed transition to massive limestone in the Poljane section remains unexplained, and is also poorly dated by fossils. One possibility is that the massive bed represents a large slump, but no in­ternal deformations were recognised and the un­derlying beds do not display any deformations. In view of this last argument, we rule out the possibility that the massive bed is a large block of a platform that slid into the basin. A third ex­planation might suggest that the section records the transition between the basin and the slope/ margin of a platform. This alternative demands further explanation as to why the Zatrnik Lime­stone continued to deposit until the lowermost Jurassic, after which it is followed by gravity deposits. Perhaps the extent of progradation was limited, or a relative rise in sea levels led to the retreat of the platform. The answer may lie in the younger parts of the Zatrnik Limestone, which remain to be logged. The predominance of micritic particles in resediments is common for the Middle Triassic – Early Carnian period, when carbonate plat­forms from slopes to tops were dominated by mi-crobialites (Keim & Schlager, 1999; Russo, 2005; Schlager & Reijmer, 2009). Most grains (bound-stone intraclasts, microproblematica) could thus have originated from the margin, slope or top of a carbonate platform (see Marangon et al., 2011). Rare fragments of green algae on the other hand surely derive from shallower parts of the adja­cent platform. An increase in resedimented skel­etal material is noted in late Tuvalian and/or ear­ly Norian (Mt. Galetovec and Poljane) sections. The Latest-Carnian increase in skeletal material is consistent with the conclusions of Martindale et al. (2017), who suggests that the shift towards the skeletal boundstones of the Dachstein-type reefs was gradual rather than sudden, and that the switch in dominant reef ecologies occurred during the late Carnian through early Norian in­terval. The lack of siliciclastic input into the Bled Ba­sin during the Carnian stands in contrast to the relatively closely situated Tolmin and Tarvisio Basins. Within the Tolmin Basin, clay-rich “Am-phiclina beds” several tens (probably hundreds) of meters thick deposited during the Carnian. This formation is dominated by black shale al­ternating with lithic sandstone and hemipelagic limestone (Car et al., 1981; Turnšek et al., 1982, 1984; Buser, 1986), whereas the uppermost part (dated as Tuvalian) consists of hemipelagic lime­stone alternating with black shale (Kolar-Jurk­ ovšek, 1982). In the Tarvisio Basin, the increase in the siliciclastics is reflected in the deposition of marlstone and marly limestone of the Tor Formation (Ogorelec et al., 1984; Gianolla et al., 2003; Gale et al., 2015). This is succeeded by a shallow-marine carbonate bank (the Portella Dolomite), followed by upper Tuvalian thin-bed­ded hemipelagic limestone and dolomite of the Carnitza Formation (Gianolla et al., 2003; Gale et al., 2015). The absence of clay input in the Bled Basin could perhaps be related to its slightly dif­ferent palaeogeographic position (e.g. a position far from some river outlet), sea currents, slope steepness, etc. Alternatively, the clay-rich part of the formation could be thin and/or covered by vegetation and has thus simply not yet been re­corded. Conclusions The Zatrnik Limestone marks the Bled Basin as a distinct paleogeographic unit. The following conclusions can be drawn from this study: - The base of the Zatrnik Limestone is Lon-gobardian in age. - The Zatrnik Limestone was deposited on a basin plain and/or distal slope of the basin. The logged succession is dominated by hemipelagic limestone and distal calciturbidites. The latter are more common in the upper Julian? to lower Tuvalian. No siliciclastic-rich interval is cur­rently recorded for the Carnian part of the for­mation. - An increase in resedimented skeletal mate­rial in calciturbidites is noted in the upper Tu­valian and/or lower Norian, marking the shift from microbe-dominated to skeletal-dominated carbonate production on the platform. Acknowledgements This research was financially supported by the Slovenian Research Agency (Programmes No. P1­ 0011 and P1-0008). We thank Camille Peybernes for discussion in determination of microproblematica, Marija Petrovic and Mladen Štumergar for the tech­nical support, and students from the University of Ljubljana who attended field work and helped with logging of the sections. Reviewers are greatly ac­knowledged for their time, feedbacks and suggestions which led to the final state of the paper. References Budkovic, T. 1978: Stratigrafija Bohinjske doline. Geologija, 21: 239-244. Buser, S. 1980: Explanatory book to Basic Geological Map SFRY 1: 100.000, Sheet Celovec (Klagenfurt). Zvezni geološki zavod, Beograd. Buser, S. 1986: Explanatory Book to Basic Geological Map SFRY 1: 100.000, Sheets Tolmin and Videm (Udine). Zvezni geološki zavod, Beograd:103 p. Buser, S. 1987: Basic Geological Map SFRY 1: 100.000, Sheets Tolmin and Videm (Udine). Zvezni geološki zavod. Buser, S. 1989: Development of the Dinaric and the Julian carbonate platforms and of the in­ termediate Slovenian Basin (NW Yugoslavia). Mem. Soc. 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CC Atribution 4.0 License https://doi.org/10.5474/geologija.2019.008 Characteristics of minerals in Slovenian marbles Znacilnosti mineralov v slovenskih marmorjih Miloš MILER1, Tanja MAŠERA2, Nina ZUPANCIC3,4 & Simona JARC3 1Geological Survey of Slovenia, Dimiceva ulica 14, SI-1000 Ljubljana, Slovenia; e-mail: milos.miler@geo-zs.si 2Brezje pri Grosupljem 79, SI-1290 Grosuplje, Slovenia; e-mail: masercaa@gmail.com 3University of Ljubljana, Faculty of Natural Sciences and Engineering, Department of Geology, Aškerceva 12, SI-1000 Ljubljana, Slovenia, e-mails: nina.zupancic@ntf.uni-lj.si; simona.jarc@ntf.uni-lj.si 4Ivan Rakovec Institute of Paleontology, ZRC SAZU, Novi trg 2, SI-1000 Ljubljana, Slovenia Prejeto / Received 23. 7. 2019; Sprejeto / Accepted 12. 11. 2019; Objavljeno na spletu / Published online 24. 12. 2019 Key words: marbles, accessory minerals, mineral assemblages, SEM/EDS, Slovenia Kljucne besede: marmorji, akcesorni minerali, mineralne združbe, SEM/EDS, Slovenija Abstract Common rock-forming and accessory minerals in marbles from various localities in Slovenia were studied using scanning electron microscopy with energy dispersive spectroscopy (SEM/EDS). Minerals and their chemical composition were identified in order to verify the variability of mineral assemblages in marbles from different localities in Slovenia. The analysis showed that marbles from Košenjak are the most mineralogically diverse, followed by Pohorje and finally Strojna marbles. Common rock-forming minerals calcite and dolomite are more abundant in Pohorje marbles where calcite contains higher levels of magnesium but no strontium and iron as compared with Strojna and Košenjak marbles. Accessory minerals like quartz, mica, titanite, apatite, rutile, zircon, chlorite group minerals, kaolinite and iron oxides/hydroxides were found in marbles from all localities. Clinopyroxene, amphibole, epidote and smectite group minerals, talc, tungsten-bearing ilmenorutile, psilomelane and bismuth oxides/carbonates, were observed only in marbles from Pohorje, while tourmaline and allanite group minerals, thorite or huttonite, chalcopyrite and synchysite group minerals were detected in marbles from Košenjak and Strojna. Variations in mineral assemblages in marbles from different locations are likely a consequence of different sedimentary environment and conditions and metamorphic grade of marble. These differences indicate that marbles from Košenjak and Strojna are genetically different from those from Pohorje and probably reflect mineral composition of the protolith. Thus, they enable rough distinction between more distant locations, but not between individual sub-localities. Izvlecek Z vrsticno elektronsko mikroskopijo, z energijsko disperzijsko spektroskopijo (SEM/EDS) smo raziskali kamninotvorne in akcesorne minerale v marmorjih z razlicnih lokacij v Sloveniji. Opredeljeni so bili minerali in njihova kemicna sestava z namenom oceniti variabilnost mineralnih združb v marmorjih. Analiza je pokazala, da so marmorji s Košenjaka mineraloško najbolj raznoliki, sledijo pohorski marmorji in marmor s Strojne. Kamninotvorna minerala kalcit in dolomit sta v najvecjih kolicinah prisotna v pohorskih marmorjih, v katerih ima kalcit višje vsebnosti magnezija kot kalcit v marmorjih s Košenjaka in Strojne, vendar ne vsebuje železa in stroncija. Akcesorni minerali, kot so kremen, sljuda, titanit, apatit, rutil, cirkon, minerali kloritne skupine, kaolinit in železovi oksidi/hidroksidi, so prisotni v marmorjih z vseh lokacij. Klinopiroksen, minerali amfibolove, epidotove in smektitne skupine, lojevec, ilmenorutil z volframom, kromit, psilomelan in bizmutovi oksidi/ karbonati so bili prisotni samo v pohorskih marmorjih, medtem ko so bili minerali turmalinove in allanitove skupine, torit ali huttonit, halkopirit in minerali sinhisitove skupine prepoznani le v marmorjih s Košenjaka in Strojne. Ugotovljene so bile razlike v mineralnih združbah v marmorjih z razlicnih lokacij, ki so verjetno posledica razlicnega sedimentacijskega okolja in pogojev ter razlicne stopnje metamorfoze marmorjev. Te razlike kažejo, da so marmorji s Košenjaka in Strojne genetsko drugacni od tistih s Pohorja in verjetno odražajo mineralno sestavo protolita. Tako omogocajo grobo razlikovanje med bolj oddaljenimi lokacijami, vendar ne med mikrolokacijami znotraj posameznih lokacij. Introduction Marble is a metamorphic rock composed most­ly of carbonate minerals, generally calcite pre­vailing over dolomite. Despite its carbonate-rich character (Blatt & Tracy, 1999), marble contains various amounts of other noncarbonate miner­als, especially silicates and oxides. The variety of noncarbonate minerals is derived by abundance of the original detrital minerals in the lime­stone and dolostone and their reactions with car­bonates during metamorphism (Blatt & Tracy, 1999). Depending on the metamorphic grade the common noncarbonate minerals are dominat­ed by quartz, brucite, phlogopite, chlorite group minerals, tremolite, diopside, forsterite, wollas­tonite, grossular, Ca-rich plagioclase and vesuvi­anite (Blatt & Tracy, 1999; Best, 2007). Therefore, the presence of noncarbonate minerals could provide information on chemistry and mineralo­gy of the protolith, and even the temperature and pressure during the process of metamorphism (Blatt & Tracy, 1999; Best, 2007). Hence, they are important tracers of the source areas of marble. In Slovenia, there are several marble out­crops on Pohorje, Strojna and Košenjak – west­ern Kozjak (Mioc, 1978; Mioc, 1983; Mioc & Žnidarcic, 1989). In the past, much attention was given to metamorphic rocks from Pohorje Mts. (Germovšek, 1954; Hinterlechner-Ravnik, 1971, 1973; Janák et al., 2004, 2005, 2006, 2009, 2015; Jarc & Zupancic, 2009; Jarc et al., 2010; Jeršek et al., 2013; Mrvar, 2013; Vrabec et al., 2010a, b; Vrabec et al., 2018). Here, the majority of medium to high-grade marbles are located in the eastern and southern parts of the massif between Oplot­nica and Dravinja brooks and in the surround­ings of Šmartno, where they are placed among gneisses, mica-schists and amphibolites (Hinter-lechner-Ravnik & Moine, 1977; Mioc, 1978). Cal­cite marbles dominate, but dolomite-containing marbles are also present. The marbles are coarse-grained to less often fine-grained with grano­blastic texture (Hinterlechner-Ravnik, 1971, 1973; Hinterlechner-Ravnik & Moine, 1977). Common accessory minerals are quartz, Na-rich plagioclase, tremolite, hornblende, diospide, mica, while garnet (mostly almandine), graphite, pyrite and chlorite, epidote, clinozoisite and ser­pentine group minerals occur rarely (Hinterlech­ner-Ravnik, 1971). Besides these, titanite, ferric oxides, vesuvianite, scapolite (Jarc & Zupancic, 2009; Jeršek et al., 2013), zircon, rutile and zoisite (Mrvar, 2013) have been found. Accessory min­erals occur in bands, and are more frequent on the edges of marble lenses (Mrvar, 2013). Marble outcrops are small, with the exception of Rimski kamnolom in Bistriški Vintgar which has a size of about 15m × 100m (Mrvar, 2013). Low to medium-grade marbles from west­ern Kozjak Mts. are bluish-greyish and lami­nated with the high content of accessory miner­als such as quartz, plagioclases, zoisite-epidote with fragments of felsic composition and phyl-lite (Hinterlechner-Ravnik, 1973). Several me­ters thick layers and small lenses of marble in Košenjak are intercalated between gneisses and mica-schist. Marbles are granoblastic, middle to coarse grained (Mioc, 1978). On Strojna, there are small outcrops of 20 cm to 50 cm thick low-grade marbles (Mioc, 1983). They contain a lot of non-carbonate minerals (e.g. quartz; Mioc, 1983). The SEM/EDS analysis enables detection of smaller accessory minerals, which have not been reported yet, and assessment of their chemical composition. The aim of this study was there­fore to characterise the accessory minerals in the marbles from different Slovenian localities by SEM/EDS analysis and to verify the local varia­bility of the mineral assemblages and their min­eral chemistry. Geological setting The Pohorje Mts., Strojna and Kozjak Mts. constitute the most south-eastern part of the Eastern Alps. Eastern Alps consist of a system of large nappes named Austroalpine of Cretaceous age that formed during the Eoalpine orogeny (Frank, 1987; Schmidt et al., 2004; Fodor et al., 2008). Pohorje nappe is the deepest tectonic unit (Janák et al., 2004; 2006), mainly composed of medium- to high-grade metamorphic rocks, e.g. gneisses and mica schists with lenses of amphi­bolite, quartzite, marble and eclogite, and north from Slovenska Bistrica also ultramafic body (SBUC) (Janák et al., 2006). The Pohorje nappe is overlain by the nappe of weakly metamorphosed Paleozoic rocks, mainly low-grade metamorphic slates and phyl-lites (Hinterlechner-Ravnik, 1971, 1973; Vrabec, 2010b). The upper-most nappe is built up of Per-mo-Triassic clastic sedimentary rocks, prevail­ingly sandstones and conglomerates (Hinter-lechner-Ravnik, 1971, 1973; Janák et al., 2004; Vrabec, 2010b). The entire nappe stack is overlain by early Miocene sediments, which belong to the syn-rift basin fill of the Pannonian Basin (Fodor et al., 2003). A large granodiorite body with dac­ite intruded in Miocene in the central part of the Pohorje massif (Dolar Mantuani, 1935; Faninger, 1970; Zupancic, 1994a, b, Trajanova et al., 2008). In the Pohorje Mts. area, the regional meta­morphism under ultra-high pressures and tem­peratures took place (Hinterlechner-Ravnik, 1971; Vrabec et al., 2012; Janák et al., 2015) dur­ing the Cretaceous Eo-Alpine Orogeny (Thony, 2002; Miller et al., 2005). The Pohorje Mts., Strojna and Kozjak Mts. have very similar lithology and structure. The Strojna is separated from Pohorje Mts. by the Labot fault and the Periadriatic fault system (Mioc, 1978; Mioc & Žnidarcic, 1989). On the southern side, the Košenjak (western Kozjak) is separated from the Pohorje Mts. by the mid-Mio­cene Ribnica trough (Mioc, 1978). Materials and methods Sampling and sample preparation A total of 24 samples of marble were collected from larger and smaller outcrops (Fig. 1). Since marble occurrences are more frequent on Pohorje Mts. and in order to check the spatial mineralog­ical diversity of the marble, 13 samples were tak­en from five different Pohorje locations, which include Hudinja (north from Vitanje; three sam­ples), a Roman quarry Rimski kamnolom, one of the largest marble outcrops (in Bistriški vintgar; three samples), Bojtina (two samples), a smaller outcrop in Zgornja Nova Vas (three samples), and Crešnova (north from Zrece; two samples). On Strojna, four samples were taken from two small (app. 2 × 2-3 m) outcrops, and on Kozjak (Košen­ jak), five samples were collected along local road in the vicinity of state border and two samples from the larger up to 20 m high outcrops near border crossing Muta. From all samples, polished thin sections were prepared for inspection with scanning electron microscopy with energy dis­persive spectroscopy (SEM/EDS). SEM/EDS analyses SEM/EDS analysis was carried out at the Ge­ological Survey of Slovenia using a JEOL JSM 6490LV SEM coupled with an Oxford Instru­ments INCA Energy 350 EDS, at an accelerat­ing voltage of 20 kV, spot size 50 and a working distance of 10 mm. The polished thin sections were carbon-coated and analysed in backscat­tered electron (BSE) mode under high vacuum. The chemical composition of individual miner­als was measured using EDS point analysis with acquisition time of 60 s. X-ray spectra were op-timised and calibrated for quantification using pre-measured standards included in the EDS software, which is a basic standardisation pro­cedure in fitted-standards EDS analysis (Gold­stein et al., 2003), referenced to a Co optimisation standard. Based on the standard ZAF-correction Fig. 1. Sampling locations (A – Strojna; B, C – Kozjak Mts. (Košenjak); D, E, F, G, H – Pohorje Mts. (D – Hudinja, E – Crešnova, F – Rimski kamnolom, G – Zgornja Nova Vas, H – Bojtina)). procedure included in the INCA Energy software (Oxford Instruments, 2006), the correction of EDS data was performed. In order to assure good quality of the EDS results, only data with devi­ ation <10 wt.% were considered for identification of minerals. Minerals were assessed by calculat­ing stoichiometric ratios from at.% of constitu­ent elements, acquired by the EDS analysis and comparison with atomic proportions of constitu­ent elements in known stoichiometric minerals, obtained from mineral databases (Wünsch, 2001; Anthony et al., 2009; Barthelmy, 2010) and EDS spectra (Welton, 1984; Severin, 2004; Reed, 2005). Mineral formulae of selected minerals were ob­ tained from mineral databases (Wünsch, 2001; Anthony et al., 2009; Barthelmy, 2010). Results and discussion The SEM/EDS analyses showed that calcite marbles prevail, but minor amount of dolomite is also present in samples from Pohorje. Although the focus of the study was determination of acces­sory minerals, the relative abundances of calcium and magnesium carbonates (calcite, dolomite) and elemental composition of calcites were also meas­ured. The list of the identified accessory minerals or mineral groups is summarised in Table 1. Common rock-forming minerals - calcite and dolomite In general, marbles from Košenjak and Stro­jna contain between 70 to 85 % and 75 to 95 % carbonates (between 5 to 30 % noncarbonate minerals), respectively, whereas Pohorje marbles consist of 95 to 97 % of carbonates (up to 5 % of noncarbonate minerals). This indicates that Po-horje marbles are purer and appear to contain fewer accessory minerals. Calcite in studied marbles is relatively pure, however it contains some magnesium, iron and strontium, which commonly substitute for calci­um in calcite (Chang et al., 1998). Minor content of magnesium in calcite was detected in samples from all locations, with the exception of Bojtina samples. Nevertheless, calcite in Pohorje mar­bles contains somewhat higher levels of magne­sium (mean of 0.42 at.%) compared with that in marbles from Košenjak (mean of 0.20 at.%) and Strojna (mean of 0.11 at.%). Iron in calcite was detected only in marble samples from Košenjak and Strojna. Strontium in calcite was found in all samples from Košenjak and Strojna, while it was not detected in samples from Pohorje. Presence of strontium is in agreement with marine aragonite (Fairbridge, 1967) but may also reflect different carbonate depositional environments. Since cal-cium/strontium ratio in calcium carbonate does not change during metamorphism (Lazzarini, 2004), and strontium is reported to be relative­ly immobile at high metamorphic grades (De Vos et al., 2006), and since high strontium contents have already been observed in high-grade mar­bles (Ofotfjorden area, Norway) whose origin was attributed to aragonitic protolith (Melezhik et al., 2003; 2013), strontium content in studied marbles probably reflects different sedimentary environment and diagenesis and metamorphic evolution. Therefore, we can assume that marbles from Košenjak and Strojna are genetically dif­ ferent from those from Pohorje. This finding is in agreement with findings of Jeršek et al. (2013) that Pohorje marble was metamorphosed from calcite prevailing protolith. Presence or absence of strontium could thus be used to distinguish marbles from Pohorje Mts. area from other local­ities. Accessory minerals The study showed that marbles from Pohor­je, despite their higher carbonate content, seem to be mineralogically as diverse as marbles from other two localities. However, the number of dif­ferent minerals or mineral groups at each specific location in Pohorje area is generally significant­ly smaller (Table 1). This could be explained by the higher number of analysed samples from this area, scattered sampling locations and the fact that Pohorje marbles are highly heterogeneous in isotopic and geochemical parameters as well as grain sizes (Jarc et al., 2010). Taking this into consideration, the highest number of identified minerals or mineral groups is found in marbles from Košenjak – beside calcite we identified 27 accessory minerals (Table 1). On the other hand, marble from Crešnova shows the lowest diversity in accessory minerals – only 10 of them have been observed (Table 1). Quartz, muscovite (some grains have elevat­ed barium content), titanite, apatite, rutile, zir­con, chlorite group minerals, kaolinite and iron oxides/hydroxides are very common and have been found in samples from all localities (Ta­ble 1). SEM/EDS analyses revealed differences in chemical compositions of some very common accessory minerals, titanite and apatite. It seems that the elemental composition of titanites de­pends on the sampling locations, as in Košenjak and Strojna marbles they have higher contents of aluminium and fluorine incorporated in their crystal structure than those in Pohorje marbles. Table 1. Mean number of identified accessory mineral grains in number (n) of samples from studied localities/locations Mineral/mineral group Sampling locality Pohorje (PO) sampling locations ST(A) KO(B, C) PO HU(D) CR(E) RK(F) ZNV(G) BO(H) n=4 n=7 n=13 n=3 n=2 n=3 n=3 n=2 Actinolite 1.2 4.7 0.5 Alkali feldspar 0.3 0.3 1.3 Allanite group 0.3 1.6 Alloclasite/cobaltite 0.1 Apatite group 3.5 2.0 2.2 1.3 3.0 2.0 2.0 3.0 Asbolane 0.3 Ba-muscovite 3.0 0.9 0.4 1.7 Bastnäsite 0.3 Bismuth/bismite/bismutite 0.1 0.3 Chalcopyrite 0.3 0.3 Chlorite group 0.3 0.4 1.4 3.7 1.0 2.0 Diopside 0.5 0.7 2.0 Epidote 0.2 1.5 Fe-oxide/hydroxide 2.0 0.7 0.2 0.3 0.3 0.3 Fluorite 0.4 Galena 0.4 Hornblende 0.2 1.0 Ilmenorutile (W) 0.1 0.3 Kaolinite 2.8 0.9 0.3 2.0 Molybdenite 0.6 Monazite group 0.3 Muscovite 2.8 3.0 0.6 0.3 1.0 2.0 Phlogopite 0.4 1.5 1.7 3.0 1.7 Plagioclase 2.4 0.8 1.3 0.3 2.5 Psilomelane 0.2 0.7 Pyrite 2.4 0.7 0.7 0.5 1.7 0.5 Pyrrhotite 2.1 0.5 1.0 1.0 1.0 Quartz 3.8 3.1 2.2 3.7 1.5 0.3 1.3 5 Rutile 1.5 1.0 0.6 0.3 0.5 1.3 0.3 0.5 Smectite group 0.5 2.3 Sphalerite 0.1 0.2 0.5 0.3 Synchysite group/petersenite 0.3 0.3 Talc 0.7 1.0 1.5 1.0 Thorite/huttonite 0.8 0.1 Titanite 0.5 3.7 1.5 1.7 1.0 1.3 1.0 2.5 Tourmaline group 1.0 0.3 Ullmannite 0.1 Uraninite 0.3 0.2 0.7 Zircon 1.0 1.9 0.5 0.3 0.3 0.3 1.5 Zoisite 1.3 0.5 0.7 0.5 1.5 . mean number of grains 24.6 31.0 18.1 18.7 12.0 21.7 12.3 26.0 Number of mineral species 18 27 27 14 10 19 11 14 ST-Strojna, KO-Košenjak, PO-Pohorje (HU-Hudinja, CR-Crešnova, RK-Rimski kamnolom, ZNV-Zgornja Nova Vas, BO-Bojtina) Fig. 2. SEM (BSE) images of: a) titanite (Ttn) grain in marble from Hudinja; b) apatite (Ap) grains in marble from Hudinja. In all samples, titanite occurs mostly as eu­hedral individual grains (Fig. 2a) in calcite or is associated with other minerals. In samples from Košenjak, titanite is associated with plagioclase, muscovite, Ba-muscovite, zoisite, fluorapatite, uraninite and also zircon, which occurs as an in­clusion in some titanite grains. In samples from Strojna, titanite was found associated with mus­covite. Titanites in samples from Hudinja, Rimski kamnolom and Zgornja Nova Vas are associated with zoisite and anorthite, phlogopite and actino-lite, and quartz, respectively. The mean sizes of ti-tanite grains are 100 µm in Košenjak samples and 62 µm in Strojna samples, while in the samples from Pohorje they range from 71 µm in Crešnova to 116 µm in Rimski kamnolom samples. Rutile, which was found in all samples (Ta­ble 1), is mostly associated with titanite. Individ­ual euhedral grains in calcite are rarely found. By its chemical composition, rutile is mostly pure, however in samples from Košenjak and Strojna rutile grains have minor contents of va­nadium and iron. It can be assumed that rutile is mostly a secondary mineral formed during met­amorphism, however individual grains in calcite could also originate from the protolith. The sizes of rutile grains are up to 25 µm in Košenjak sam­ples, up to 68 µm in Strojna samples. In the Po-horje samples they range from 5 µm in Crešnova to 35 µm in Bojtina samples. Apatite is also found in samples from all lo­calities (Table 1). All measured apatite grains contain fluorine, whose content depends on the location. Apatite in marble samples from Košen­jak and Strojna has higher fluorine contents than those in Pohorje marbles, while those in Pohorje marbles has also minor content of chlorine. Ap­atite mainly forms euhedral rounded to elongat­ed grains with isometric cross-sections (Fig. 2b) as individual grains in calcite or in association with other minerals. In samples from Košenjak, it is associated with phlogopite, plagioclase (al-bite and oligoclase), muscovite and quartz. Ap­atite in samples from Strojna is associated with iron oxides/hydroxides. In samples from Hudin­ja and Rimski kamnolom, it is accompanied by dolomite, while in Zgornja Nova Vas and Bojtina samples apatite is associated with muscovite and plagioclase, respectively. The mean sizes of apa­tite grains are 106 µm in Košenjak samples and 85 µm in Strojna samples, while in the samples from Pohorje they range from 76 µm in Zgornja Nova Vas to 231 µm in Hudinja samples. Tourmaline and allanite group minerals, thorite or huttonite, chalcopyrite and miner­als of synchysite group (Ca(Ce,La)(CO3)2F), or pseudomorphs of synchysite after petersenite ((Na,Ca)4(Ce,La,Nd,Sr)2(CO3)5), were detected in samples from Košenjak and Strojna, but not in Pohorje marbles. Tourmaline grains with com­position of uvite or dravite are euhedral, zoned and up to 200 µm in size. They are associated with rutile and illite. Grains of allanite group minerals are zoned, anhedral and up to 70 µm large. They occur individually in calcite or ac­company quartz and pyrite. Anhedral chalco-pyrite grains of 50 µm in size form assemblages with pyrite and muscovite in Košenjak marbles and with kaolinite and rutile in Strojna marbles. Plagioclase, phlogopite, zoisite, pyrite, pyrrh­otite, sphalerite and uraninite were observed in marbles from Košenjak and Pohorje. Composi­tions of plagioclase vary from albite to anorthite. Anorthite was present particularly in Košenjak and Hudinja samples. In some samples (Strojna and Pohorje), alkali feldspar (e.g. anorthoclase) is present (Table 1). Phlogopite occurs as subhedral (in Košenjak) to anhedral (in Pohorje samples) flakes with elongated cross-sections with size of up to 550 µm. Phlogopite forms assemblages with apatite and titanite in Košenjak and with talc, dolomite, chlorite group minerals and illite in Pohorje marbles. Zoisite is up to 200 µm large in all marbles. In Košenjak marbles it is elongat­ed and subhedral and associated with quartz, ti-tanite and pyrite, while in Pohorje marbles it is anhedral and found as inclusions in plagioclase or kaolinite grains. In some grains of zoisite in Košenjak samples, minor content of strontium was detected. Some pyrite grains in Košenjak samples contain minor level of nickel, while some pyrites from Pohorje (Rimski kamnolom) sam­ples contain either minor level of cobalt or ar­senic. Also, some pyrrhotite grains in Košenjak and Pohorje (Rimski kamnolom, Bojtina) samples contain minor level of nickel. Pyrite and pyrrh­otite commonly form assemblages with other sul­phides. Sphalerite is subhedral with isometric cross-sections and up to 34 µm large and forms assemblages with pyrrhotite, pyrite with molyb­denite inclusion and quartz. Some minerals were found only in marbles of a specific metamorphic grade and from a spe­cific location, which could be a consequence of different sedimentary environment and con­ditions and/or degree of metamorphism. Thus, anhedral void-filling fluorite, galena (subhedral inclusions in pyrite and pyrrhotite), molybdenite (also with minor content of tungsten), ullmannite (NiSbS) and ((Co,Fe)AsS) or cobaltite (CoAsS) were found only in marbles from Košenjak, while monazite group minerals (subhedral grains in calcite), bastnäsite ((Ce,La)(CO3)F) and asbolane ((Ni,Co)xMn(O,OH)4·nH2O) are present only in Strojna marbles. Clinopyroxene (e.g. diopside, augite) (anhedral and associated with actinolite), amphibole (hornblende, actinolite) (subhedral to anhedral and associated with pyrite, apatite, titanite, dolomite) and epidote group miner­als (euhedral in assemblage with chlorite group minerals and quartz), talc (elongated anhedral and associated with phlogopite, chlorite group minerals and dolomite), smectite group minerals, tungsten-bearing ilmenorutile ((Ti,Nb,Fe)O2), psilomelane (anhedral fillings in chlorite group minerals and quartz or euhedral needle-like crystals along cleavage planes in dolomite) and bismuth oxides or carbonates were observed only in Pohorje marbles. This could also result from highly variable mineral composition of marbles and the relatively small number of inspected samples. For example, epidote was observed only in samples from Bojtina, but other researchers detected it also in marbles from other localities on Pohorje (Jarc & Zupancic, 2009; Jarc et al., 2010; Jeršek et al., 2013) and Košenjak (Komar, 2006). Diopside was also previously found in Bo-jtina (Jeršek et al., 2013), in the surroundings of Crešnova (Hinterlechner-Ravnik, 1971) and Slov­enska Bistrica (Mrvar, 2013). This shows that the marbles are very heterogeneous, also regarding content and type of accessory minerals. The mineral assemblages of index minerals, which indicate the degree of metamorphism ac­cording to Blatt & Tracy (1999), are similar in all studied marbles and show similar metamorphic grades (Table 1). However, the greatest amount of minerals typical of low metamorphic grades (e.g.muscovite, chlorite group, rutile, albite) was found in Košenjak and Strojna marbles. Miner­als of medium metamorphic grades (e.g. titanite, epidote, hornblende, diopside) are most abundant in Košenjak marbles, while minerals indicat­ing high metamorphic grades (e.g. zoisite, alkali feldspar, phlogopite) prevail in Pohorje marbles. This is consistent with high-grade metamorphic rocks of Pohorje Mts. (Hinterlechner-Ravnik, 1971; Vrabec et al., 2012; Janák et al., 2015) and with low metamorphic grades reported for Stroj­ na marbles (Mioc, 1983). Some minerals described in this study have been observed for the first time in Slovenian mar­bles. These minerals are synchysite group miner­als or pseudomorphs of synchysite after petersen­ite, bastnäsite, tungsten-bearing ilmenorutile, ullmannite, asbolane, alloclasite or cobaltite, bismuth/bismuth oxides or carbonates, thorite or huttonite, uraninite and molybdenite. Synchysite group minerals, or pseudomorphs of synchysite after petersenite, occur as up to 40 µm large an-hedral aggregates of fibrous crystals in kaolinite (Fig. 3a), which are in Strojna samples associated with 29 µm large anhedral grains possibly of min­eral bastnäsite. Synchysite fibrous crystals can also be found along cracks in grains of allanite group minerals or along the calcite-mica bound­aries. Both synchysite and bastnäsite are possibly secondary minerals that could have formed due to local hydrothermal activity. Synchysite has al­ready been found in low-grade high REE-marbles within biotite phyllites of Horní Dunajovice in Western Moravia, where REE enrichment was as­cribed to protolith composition and formation of synchysite to early metamorphosis (Houzar et al., 2004). Others reported synchysite in high-grade marbles, e.g. in Otter Lake area (Quebec), occur­ring as inclusions within fluorapatite together with some other rare accessory minerals, such as allanite and thorite (Martin et al., 2017). Bast-näsite was observed also in carbonatite related, altered dolomite marble in Bayan Obo (Mongolia) (Smith et al., 1999). Uraninite is mostly chemical­ly pure, but some grains may also contain minor level of thorium. It forms euhedral to subhedral subrounded grains with sizes ranging between 3 µm and 16 µm and mostly isometric cross-sec­tions. They are associated with about 6 µm large anhedral grain of tungsten-bearing ilmenorutile, pyrite (Fig. 3b) and titanite and only few grains are found individually in dolomite and calcite. Ullmannite occurs as euhedral to subhedral grain with size of about 5 µm associated with pyrrhotite (Fig. 3c). Ullmannite has been report­ed in medium to high-grade metamorphic meta-sedimentary rocks from hydrothermal solutions (Dobbe, 1991), but was also found in low-grade dolomite marbles in Watten valley (Austria) (Ha-ditsch & Mostler, 1983). Asbolane is up to 12 µm large anhedral and plumose aggregates of fibrous crystals filling voids and cracks at the contact be­tween mica and calcite (Fig. 3d). Its morphology and form of occurrence indicate that it is a sec­ondary mineral. Alloclasite or cobaltite (Fig. 4a) forms a 4 µm large euhedral inclusion in pyrrh­otite, which is associated with a grain of biotite group mineral. About 1 µm large elongated and subhedral inclusion of bismuth/bismuth oxide or carbonate (Fig. 4b) was found in pyrrhotite at the boundary with calcite. No reports on asbolane, al­loclasite or cobaltite and bismuth/bismuth oxide or carbonate occurrences in marbles have been found. Thorite or huttonite occurs as euhedral to subhedral grains of 30 µm in size (Fig. 4c), most­ ly as inclusions in Ba-muscovite or in association with quartz, zircon and pyrite. Some grains ap­pear to be intergrown with yttrialite. Ditz et al. (1990) reported thorite in metasomatised impure marbles near contacts of granitic and pegmatit­ic intrusions of Grenville subprovince (Canada), while Drábek et al. (2017) found thorite together with molybdenite, pyrite, pyrrhotite, galena and chalcopyrite also in regionally metamorphosed medium to high-grade carbonatite-like marble at Bližná. Molybdenite forms laths or tabular crystals with grain sizes ranging between 13 µm and 38 µm. They are mostly enclosed in pyrite or in mica (Fig. 4d) and quartz. Some molybdenite grains contain minor levels of tungsten. No re­ports on molybdenite in marbles have been found, however, lath-like tungsten rich molybdenite was found in granite rocks within orthogneiss at Vít­ kov (Bohemian Massif, Czech Republic) (Pašava et al., 2015). Since these rare minerals occur in many dif­ferent metamorphic rocks (including marbles) varying in metamorphic grade, they could not be considered as definite indicators of metamorphic grade. Some minerals that were reported in the liter­ature, such as garnet, graphite, serpentine group minerals (Hinterlechner-Ravnik, 1971), tremo-lite (Jarc & Zupancic, 2009; Mrvar, 2013), vesu­vianite (Jeršek et al., 2013) and scapolite (Jeršek et al., 2013; Mrvar, 2013), were not observed in our study. This indicates the highly heterogene­ous mineral assemblages in marbles from studied sites. Conclusions Marbles from Pohorje Mts. are relatively pure, composed mostly of carbonate and containing only up to 5 % of noncarbonate minerals, while marbles from Košenjak and Strojna localities contain from 5 % to 30 % of noncarbonate min­erals. Marbles from Košenjak are mineralogically the most diverse. Beside calcite, we recognized 27 minerals or mineral groups, while in mar­bles from Crešnova only 10 minerals or miner­al groups besides calcite and dolomite were de­tected. Some minerals like quartz, mica, titanite, apatite, rutile, zircon, chlorite group minerals, kaolinite and iron oxides/hydroxides are very common and were found in marbles from all lo­calities. Other minerals, such as clinopyroxene, amphibole, epidote, and smectite group minerals, talc, tungsten-bearing ilmenorutile, psilomelane and bismuth oxides or carbonates, were observed only in samples from Pohorje Mts., while tourma­line and allanite group minerals, thorite or hut-tonite, chalcopyrite and minerals of synchysite group, or pseudomorphs of synchysite after pe­tersenite, were detected in marbles from Košen­jak and Strojna. Further, SEM/EDS analysis showed the dif­ferences in chemical composition of calcite, titan-ite and apatite in marbles from different locali­ties. Namely, calcites in samples from Košenjak and Strojna contain detectable amounts of stron­tium, which is not detected in Pohorje samples. Titanites from Košenjak and Strojna contain higher level of aluminium and fluorine than those from Pohorje marbles. Apatite in marbles from Košenjak and Strojna has also higher content of fluorine than those from Pohorje marbles, howev­er it does not contain chlorine, which is present in apatite from Pohorje. Fig. 3. SEM (BSE) images and EDS spectra of: a) grain of synchysite group mineral (Sp. 1), or pseudomorph of synchysite after petersenite in kaolinite (Kln) (marble from Košenjak); b) uraninite (Sp. 2) associated with pyrite (Sp. 3) (marble from Košenjak); c) ullmannite (Sp. 4) grain associated with pyrrhotite (Po) (marble from Košenjak) and d) asbolane (Sp. 5) aggrega­tes at the contact between mica (Mca) and calcite (Cal) (marble from Strojna). Fig. 4. SEM (BSE) images and EDS spectra of: a) inclusion of alloclasite or cobaltite (Sp. 1) in pyrrhotite (Po) (marble from Košenjak); b) inclusion of bismuth/bismuth oxide or carbonate (Sp. 2) in pyrrhotite (Po) at the boundary with calcite (Cal) (marble from Rimski kamnolom); c) thorite or huttonite (Sp. 3) associated with zircon (Zrn) and pyrite (Py) (marble from Košenjak) and d) molybdenite (Sp. 4) crystal enclosed in mica (Mca) (marble from Košenjak). In all investigated marbles, 39 minerals or mineral groups were identified besides calcite and dolomite. For the first time in Slovenian marbles, minerals of synchysite group, or pseudomorphs of synchysite after petersenite, bastnäsite, tung-sten-bearing ilmenorutile, ullmannite, asbolane, alloclasite or cobaltite, bismuth/bismuth oxides or carbonates, thorite or huttonite, uraninite and molybdenite were observed. Although there are some differences in min­eral assemblages between marbles from different locations, which are likely a consequence of dif­ferent sedimentary environment and conditions and degree of metamorphism, they could also re­flect heterogeneous nature of investigated marble sites and limited number of inspected samples. Based merely on mineral assemblages, we cannot argue to distinguish between marble localities of the three different massifs. However, the differences in composition of very common minerals, such as calcite, titanite and apatite that are widespread in marbles from all three massifs, should enable rough distinction between more distant locations and marbles of different metamorphic grades, but not between individual sub-localities. Established differences in mineral assemblag­es and chemical composition of common miner­als could be useful for identification of sources of marbles. Acknowledgements The authors acknowledge the financial support from the state budget of the Slovenian Research Agency obtained through the research programs “Geochemical and structural processes” (No. P1-0195) and “Paleontology and Sedimentary Geology” (No. P1-0008) and post-doc research project “Source iden­tification of solid pollutants in the environment on the basis of mineralogical, morphological and geochemi­cal properties of particles” (Z1-7187). The study was partly supported by UNESCO and IUGS project IGCP 637: Heritage Stone Designation. We are also grateful to technical co-worker Ema Hrovatin for help with the preparation of samples. References Anthony, J.W., Bideaux, R.A., Bladh, K.W. & Nichols, M.C. 2009: The Handbook of Mineralogy. Mineralogical Society of America. Internet: http://www.handbookof­ mineralogy.org/ Barthelmy, D. 2010: The Mineralogy Database. Internet: http://webmineral.com/ Best, M.G. 2007: Igneous and metamorphic petro­logy. 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Internet: http://www.lithos-mi­ neralien.de Zupancic, N. 1994a: Petrographical characte­ristics and classification of magmatic rocks of Pohorje. Rudarsko-metalurški zbornik, 41: 101–112 (in Slovenian with English summary). Zupancic, N. 1994b: Geochemical characteristi­cs and origin of magmatic rocks of Pohorje. Rudarsko-metalurški zbornik, 41: 113–128 (in Slovenian with English summary). GEOLOGIJA 62/2, 189-218, Ljubljana 2019 © Author(s) 2019. CC Atribution 4.0 License https://doi.org/10.5474/geologija.2019.009 Provenance and morphostratigraphy of the Pliocene-Quaternary sediments in the Celje and Drava-Ptuj Basins (eastern Slovenia) Provenienca in morfostratigrafija pliocensko-kvartarnih sedimentov v Celjskem in Dravsko-Ptujskem bazenu (vzhodna Slovenija) Eva MENCIN GALEa, b, d, Petra JAMŠEK RUPNIKa, Mirka TRAJANOVAa, Luka GALEa, c, Miloš BAVECa, Flavio S. ANSELMETTIb & Andrej ŠMUCc aGeološki zavod Slovenije, Dimiceva ulica 14, SI-1000 Ljubljana, Slovenija bUniverza v Bernu, Institute of Geological Sciences and Oeschger Centre for Climate Change Research, Baltzerstrasse 1+3, 3012 Bern, Švica cUniverza v Ljubljani, Naravoslovnotehniška fakulteta, Oddelek za geologijo, Aškerceva c. 12, SI-1000 Ljubljana, Slovenija dUniverza v Ljubljani, Fakulteta za gradbeništvo in geodezijo, Jamova c. 2, SI-1000 Ljubljana, Slovenija e-mails: eva.mencin-gale@geo-zs.si, petra.jamsek@geo-zs.si, mirka.trajanova@geo-zs.si, milos.bavec@geo-zs.si, flavio.anselmetti@geo.unibe.ch, andrej.smuc@geo.ntf.uni-lj.si Prejeto / Received 19. 9. 2019; Sprejeto / Accepted 19. 11. 2019; Objavljeno na spletu / Published online 24. 12. 2019 Key words: Quaternary sedimentology, intramountane, geomorphology, river terrace, clast lithological analysis Kljucne besede: sedimentologija kvartarja, medgorski bazen, geomorfologija, recna terasa, litološka analiza klastov Abstract This study presents the results of the first systematic morphostratigraphic and provenance analyses of the Pliocene-Quaternary fluvial sediments in the Celje and Drava-Ptuj intramontane basins. Based on the degree of terrace preservation, the dip of the terrace surfaces and fans, and the composition and degree of weathering of the sediments, low-, middle- and high-level terrace groups were constrained and tentatively attributed to Late Pleistocene, Middle Pleistocene and Plio-Early Pleistocene, respectively. The provenance analysis focused on the sediments from the high-level terrace (Plio-Early Pleistocene) and encompassed clast lithological analysis and microfacies analysis of the clasts. The results indicate a local provenance with relatively short transport, which is consistent with the morphology of the clasts. The source rocks of the Plio-Early Pleistocene deposits in the Celje Basin are attributed to the formations outcropping in the southern Pohorje Massif and the Upper Savinja River Valley corresponding to the paleo-Savinja. The possibility of resedimentation of the clasts from Miocene clastic sedimentary rocks located north of the Celje Basin also needs to be considered. The sediments of the Drava-Ptuj Basin originate from the Pohorje Massif, the Kozjak mountain range, and the area south of the Pohorje Massif which were deposited by the paleo-Drava and paleo-Dravinja rivers. Our study indicates that the drainage systems of the paleo-Savinja, paleo-Drava and paleo-Dravinja during the Plio-Early Pleistocene roughly correspond to those of the present day. Izvlecek Predstavljamo prve sistematicne analize morfostratigrafije in provenience pliocensko-kvartarnih recnih sedimentov na obmocju Celjskega in Dravsko-Ptujskega medgorskega bazena. Na podlagi stopnje ohranjenosti morfologije teras, naklona terasnih površin in sestave ter stopnje preperelosti sedimentov so bili opredeljeni trije terasni nivoji in interpretirane starosti teras in vršajev. Spodnjemu terasnemu nivoju je bila interpretativno dolocena poznopleistocenska starost, srednjemu terasnemu nivoju srednjepleistocenska, zgornjemu terasnemu nivoju pa plio-zgodnjepleistocenska starost. Analiza provenience je bila osredotocena na sedimente višjega terasnega nivoja (pliocen-zgodnji pleistocen) in je temeljila na litološki analizi klastov in analizi mikrofaciesov klastov. Rezultati nakazujejo, da gre za lokalno provenienco proda, kar dodatno potrjujejo sedimentološka opazovanja morfologije klastov. Izvor plio-zgodnjepleistocenskih sedimentov v Celjskem bazenu so domnevno formacije, ki izdanjajo na obmocju južnega Pohorja in Zgornjesavinjske doline, pri cemer pa moramo upoštevati E.MENCIN GALE, P. JAMŠEK RUPNIK, M. TRAJANOVA, L. GALE, M. BAVEC, F. S. ANSELMETTI & A. ŠMUC možnost resedimentacije nekaterih litologij iz miocenskih klasticnih sedimentnih kamnin, ki se nahajajo severno od bazena. Prod v Dravsko-Ptujskem bazenu pa verjetno prihaja z obmocja Pohorja, Kozjaka in obmocja južno od Pohorja. Ugotovljeno je bilo, da je plio-zgodnjepleistocenska recna mreža generalno sovpadala z današnjo. Tako lahko recemo, da so se plio-zgodnjepleistocenski sedimenti na obmocju Celjskega bazena odlagali s paleo-Savinjo in njenimi pritoki, sedimenti na obmocju Dravsko-Ptujskega bazena pa s paleo-Dravo, paleo-Dravinjo in njunimi pritoki. Introduction The Slovenian territory is located at the junc­ tion of the Alps, Dinarides and Pannonian Basin (Placer, 2008). The Cenozoic tectonic activity re­sponsible for uplift of the Alps and Dinarides re­sulted in a morphologically diverse landscape and the formation of intramontane basins. These ba­sins were rapidly filled due to intensive post-Ne­ogene erosion related to the eustatic sea-lev­el changes and Quaternary compression of the area. Plio-Early Pleistocene (“Plio-Quaternary” according to e.g. Buser, 2010 and other Slovenian authors) sediments mark the onset of the young­est terrestrial sedimentation active up to now in the area of South, East and Central Slovenia (Fig. 1A). According to current interpretations, these sediments represent informal stratigraphic unit named “Plio-Quaternary” comprised by i) the sediments that were filling the Pannonian Lake, ii) terrestrial sediments of intramontane basins and iii) sediments resulted from weathering of host rock and their subsequent resedimentation (Markic, 2009, and references within). Plio-Early Pleistocene sediments of intramon­tane basins in the wider area of Maribor, Slovenj Gradec, Velenje, Nazarje, Celje, Crnomelj, Kocev­je and Krško are composed of interlayered beds of gravel, sand, silt and clay (Mioc, 1978; Buser, 1979; Šikic et al., 1979; Premru, 1983; Bukovac et al., 1984; Mioc & Žnidarcic, 1989; Verbic, 2004) deposited in fluvial, swamp, and lacustrine envi­ronments. The gravel clasts are composed of ig­neous, metamorphic and sedimentary rocks. Rare previous provenance research points to i) local origin (Mioc, 1978), ii) non-local origin, sediments were transported by paleo-flows of current rivers (i.e. paleo-Sava; Verbic, 2004). Based on the rela­tive and numeric data, the age of these sediments was defined only in the area of Velenje and Krško. In the Velenje Basin, a Plio-Early Pleistocene age of 2,6 to 3,5 million years (Villafranchian, mam­mal zone MN16: Debeljak, 2017) was determined based on the finding of fossil mastodonts (Drobne, 1967; Rakovec, 1968) and palaeontological find­ings in coal (Brezigar, 1987; Brezigar et al., 1987; Markic & Sachenhofer, 2010). In the Krško Ba­sin, a Plio-Early Pleistocene age was determined Uvod Obmocje Slovenije leži na sticišcu Alp, Di-naridov in Panonskega bazena (Placer, 2008). V obdobju kenozoika se je zaradi tektonskih pro-cesov, ob katerih so se med drugim dvigale Alpe in Dinaridi, oblikovala reliefno razgibana po­krajina. Intenzivna poznoneogenska erozija, po­vezana tudi z evstaticnimi spremembami višine morske gladine, in kvartarna kompresija, sta znatno prispevali k povecani sedimentaciji v nastalih medgorskih bazenih. Plio-zgodnjeplei­stocenski (»pliokvartarni« v npr. Buser, 2010 ter v ostali dosedanji literaturi slovenskih avtorjev) sedimenti oznacujejo zacetek najmlajše, še danes potekajoce terestricne sedimentacije na obmocju današnje osrednje, južne in vzhodne Slovenije (sl. 1A). Po trenutnih interpretacijah neformalno enoto »pliokvartar« tako predstavljajo: i) nanosi sedimentov, ki so zasipavali Panonski bazen, ii) terestricni sedimenti odloženi v medgorskih ba­zenih ter iii) sedimenti nastali s preperevanjem maticne kamnine in njihovo kasnejšo resedimen­tacijo (Markic, 2009 z referencami). Plio-zgodnjepleistocenske sedimente (»plio­kvartar« po npr. Buser, 2010) medgorskih baze­nov na širšem obmocju Maribora, Slovenj Grad-ca, Velenja, Nazarij, Celja, Crnomlja, Kocevja in Krškega predstavlja menjavanje nesprijetega proda, peska, melja in gline (Mioc, 1978; Buser, 1979; Šikic et al., 1979; Premru, 1983; Bukovac et al., 1984; Mioc & Žnidarcic, 1989; Verbic, 2004), ki so se odlagali v recnih, mocvirskih in jezerskih okoljih. Med prodniki najdemo razlicke magmat­skih, metamorfnih in sedimentnih kamnin. Red-ke predhodne raziskave provenience kažejo, da so sedimenti lokalnega izvora (Mioc, 1978), ozi­roma prineseni s paleotokovi današnjih rek (npr. paleo-Sava; Verbic, 2004). Starost sedimentov je bila na podlagi relativnih in numericnih me-tod dolocena le na obmocju Velenja in Krškega. V Velenjskem bazenu je starost plio-zgodnjeplei­stocenskih sedimentov dolocena na podlagi najd-be mastodonta (Drobne, 1967; Rakovec, 1968) in paleontoloških raziskav premoga (Brezigar, 1987; Brezigar et al., 1987; Markic & Sachenhofer, 2010) ter znaša od 2,6 do 3,5 milijona let (biokronološka enota spodnji villafranchij, sesalska cona MN 16; based on paleontological correlations (Šikic et al., 1979), morphostratigraphy (Verbic, 2008) and numerical dating (Cline et al., 2016), indicating a minimal age of 1,79 million years. Only few studies exsist on poorly investigat­ed Plio-Early Pleistocene sediments in the area of Slovenia (Plenicar & Ramovš, 1954; Štern & Lapajne, 1974; Brezigar, 1987; Brezigar et al., 1987; Kralj, 2001; Markic & Rokavec, 2002; Ver­bic, 2004). The reasons are lack of outcrops and subsurface data, degraded and poorly preserved Plio-Early Pleistocene terraces and the fact that the sediments are usually strongly weathered. Therefore, the knowledge of Plio-Early Pleisto­cene sedimentary evolution represents a scientif­ic gap not only in the area of Slovenia but also in a wider pan-Alpine realm. This study focuses on composition and prov­enance of the Celje (CB) and Drava-Ptuj (DPB) basins (Fig. 1B). The study is based on systematic approach using morphostratigraphic and sedi­mentological methods established in the field of Quaternary geology. The aim of this research is to determine morphostratigraphy of terrace sys­tems, to define provenance of Plio-Early Pleisto­cene sediments and to interpret the evolution of the fluvial system in the Plio-Early Pleistocene. Geological Setting Celje Basin (CB) The CB is located north of the Sava Hills, east of the Menina planina and Dobrovlje, and south of the Vitanje-Konjice part of the Karavanke Moun­tains. The present-day fluvial system is governed by the river Savinja, originating in the Logarska Valley in the Kamnik-Savinja Alps, and running in a northwest–southeast direction. In addition to the river Savinja, smaller streams drain into the basin from the northern and southern rims. The northwestern rim of the CB borders the Smreko­vec volcanic complex of Oligocene age (Kralj, 1996; Pamic & Balen, 2001; Premru, 1983). The wider area also comprises Carboniferous siliciclastic rocks, Permian carbonates, Triassic carbonate and volcanic rocks, Jurassic and Cretaceous carbonate rocks, as well as Neogene carbonate and siliciclas-tic sediments and sedimentary rocks (Buser, 2010). The mentioned Paleozoic and Mesozoic rocks structurally belong to the Southern Alps and the Dinarides, while sediments and rocks of Oligocene and Miocene age were deposited near the margins of the Pannonian Basin (Placer, 1999; 2008; Kovác et al., 2007). The Pliocene-Quaternary sediments of the CB comprise the 35 m thick “Plio–Quater-Debeljak, 2017). V Krškem bazenu je bila starost plio-zgodnjepleistocenskih sedimentov dolocena na podlagi paleontoloških korelacij (Šikic et al., 1979), morfostratigrafije (Verbic, 2008) in nume­ricnih datacij (Cline et al. 2016). Slednje kažejo na minimalno starost 1,79 milijona let. Plio-zgodnjepleistocenski sedimenti so na ob-mocju Slovenije sorazmerno slabo raziskani ozi­roma študije, ki se nanašajo nanje, tematiko opi­sujejo le obrobno (Plenicar & Ramovš, 1954; Štern & Lapajne, 1974; Brezigar, 1987; Brezigar et al., 1987; Kralj, 2001; Markic & Rokavec, 2002; Verbic, 2004). Temu botruje dejstvo, da so izdanki in glo­binski podatki redki, plio-zgodnjepleistocenske terase so pogosto slabo ohranjene in mocno degra­dirane, sedimenti pa so pogosto mocno prepereli. Slaba raziskanost zato predstavlja vrzel v kvar­tarni geologiji ne le na obmocju današnje Slove­nije, temvec tudi v širšem predalpskem prostoru. V tej študiji smo se osredotocili na sesta­vo in provenienco plio-zgodnjepleistocenskih sedimentov v Celjskem (CB) in Dravsko-Ptu­jskem bazenu (DPB) (sl. 1B). Raziskava temelji na sistematicnem pristopu z uporabo ustreznih morfostratigrafskih in sedimentoloških metod uveljavljenih v kvartarni geologiji, s katerimi smo opredelili morfostratigrafijo sistema teras, ovrednotili izvorna obmocja plio-zgodnjepleisto­censkih sedimentov ter interpretirali razvoj rec­ne mreže v obdobju plio-pleistocena. Geologija obmocja Celjski bazen (CB) CB se nahaja na severno od Posavskega hri­bovja, vzhodno od Menine planine in Dobrovelj ter južno od Vitanjsko-Konjiških Karavank. Današnja recna mreža CB je pogojena z njenim glavnim vodotokom, Savinjo, ki izvira v Logar-ski dolini v Kamniško-Savinjskih Alpah in tece v smeri severozahod-jugovzhod. Poleg tega se v bazen drenirajo njeni manjši pritoki iz severnih in južnih obronkov kotline. Severozahodno obro­bje bazena meji na Smrekovški vulkanski kom­pleks oligocenske starosti (Kralj, 1996; Pamic & Balen, 2001; Premru, 1983). Na širšem obmocju se nahajajo še karbonske klasticne kamnine, perm-ske karbonatne kamnine, triasne karbonatne in vulkanske kamnine, kredne in jurske karbonatne kamnine ter neogenske karbonatne in klasticne kamnine ter sedimenti (Buser, 2010). Omenjene paleozojske in mezozojske kamnine strukturno pripadajo Južnim Alpam in Dinaridom, oligo­censke in miocenske kamnine pa so se odložile v robnih delih Panonskega bazena (Placer, 1999, E.MENCIN GALE, P. JAMŠEK RUPNIK, M. TRAJANOVA, L. GALE, M. BAVEC, F. S. ANSELMETTI & A. ŠMUC Fig. 1. Research area. (A) The area of Slovenia with geotectonic units marked (modified after Placer, 2008), and the spatial di­stribution of the Plio-Early Pleistocene sediments (so-called “Plioquaternary”). (B) Geological map of the Celje (1) and Drava-Ptuj (2) intramontane basins (modified after Buser, 2010). Abbreviations: MS: Magdalensberg series, SVC: Smrekovec volcanic complex, LF: Lavantall fault, ŠF: Šoštanj fault, CF: Celje fault, PF: Periadriatic fault, LJF: Ljutomer fault, DF: Donat fault. Sl. 1. Obmocje raziskave. (A) Obmocje Slovenije z glavnimi geotektonskimi enotami (prirejeno po Placer, 2008) in pojavnostjo plio-zgodnjepleistocenskih sedimentov (t.i. »pliokvartarja«). (B) Geološka karta širšega obmocja Celjskega (1) in Dravsko-Ptujskega (2) medgorskega bazena (prirejeno po Buser, 2010). Na karti so oznacena glavna izvorna obmocja kamnin. Okrajšave: MS: Štalenskogorska serija, SVC: Smrekovški vulkanski kompleks, LF: Labotski prelom, ŠF: Šoštanjski prelom, CF: Celjski prelom, PF: Periadriatski prelom, LJF: Ljutomerski prelom, DF: Donacki prelom. nary” non-carbonate gravel, while the younger, Quaternary gravel deposits reach up to 25 m in thickness (Buser, 1979). The “Plio–Quaternary” deposits lie on Oligocene and Triassic basement (Fig. 1b; Buser, 1979). CB represents structurally the northernmost part of the Sava compressive wedge (Placer, 1998a, 1998b), which is reflected in the folding of its pre-Pliocene basement (the Celje syncline sensu Buser, 1977). The syncline’s axis runs in an east–west direction, indicating post-Miocene compression in the north–south di­rection (Buser, 1977; Placer, 1998). According to Vrabec and Fodor (2006), the CB lies within the still active Periadriatic dextral transpressive fault system, experiencing local transtension between the faults running along the basin’s margin. Drava-Ptuj Basin (DPB) The Drava-Ptuj Basin (DPB) is situated south­east of the Pohorje Massif and north of the Sava Hills. Its present-day fluvial system comprises the main river Drava, running in a north-northwest– south-southeast direction, and numerous smaller tributaries, following the direction of the Drava river, or generally flowing from the (north)west to the (south)east. The pre-Quaternary basement of the DPB belongs to several geological units (Fig. 1b). West to northwest of the DPB lies the Pohorje Massif built of low-, medium-, to (ultra) high-metamorphic rocks of the Pohorje metamor­phic complex, overthrusted by very low-grade metamorphic rocks of the Magdalensberg series, unconformably overlain by Permo-Triassic, Cre­taceous, and Miocene rocks and sediments (Mioc, 1978; Hinterlechner-Ravnik, 1971, 1973, 1982; Janák et al., 2004; Janák et al., 2005; Vrabec et al., 2012). The central part of the Pohorje Massif is formed of a pluton and sub-volcanic varieties of granodioritic to tonalitic composition, emplaced during the Miocene (Zupancic, 1994a, 1994b; Altherr et al., 1995; Fodor et al., 2008; Trajanova et al., 2008; Trajanova, 2013). From the structural point of view, the pre-Neogene rocks belong to the Eastern Alps. Miocene sediments and sedimenta­ry rocks of the Maribor subbasin near the western margin of the Central Paratethys sea, filling the depression of the Pannonian Basin (Jelen & Rife-lj, 2011; Trajanova, 2013). The deposition of Plio– Early Pleistocene sediments in this area started after the final regression of the Central Paratethys (Markic, 2009). According to Mioc and Žnidarcic (1989), the Plio–Early Pleistocene sediments in the DPB reach thickness up to 65 m, while the Qua­ternary deposits are only 30 m thick. The latter comprise four river terraces (Mioc & Žnidarcic, 2008; Kovác et al., 2007). Pliocensko-kvartarni sedimenti v CB obsegajo »pliokvartarni« nekar­bonatni prod v skupni debelini 35 m, medtem ko mlajši, karbonatni kvartarni prod dosega debe-line do 25 m (Buser, 1979). Podlago »pliokvar­tarja« v sami kotlini predstavljajo oligocenske in triasne kamnine (sl. 1b; Buser, 1979). V ožjem strukturnem smislu je po nekaterih interpretaci­jah kotlina še del Savskega kompresijskega klina (Placer, 1998a, 1998b), na kar kaže sinklinalna upognjenost predpliocenskih kamnin in sedi­ mentov (Celjska sinklinala po Buser, 1977). Os sinklinale, ki poteka v smeri vzhod-zahod, kaže na post-miocensko kompresijo v smeri sever-jug (Buser, 1977; Placer, 1998). Po aktualnejših inter-pretacijah se kotlina nahaja znotraj aktivnega desno transpresivnega Periadriatskega sistema prelomov, kjer se odvija rotacija strižnih lec, pri cemer je obmocje CB verjetno podvrženo lokal­ni transtenziji med posameznimi prelomi, ki ga obkrožajo (Vrabec in Fodor, 2006). Dravsko-Ptujski bazen (DPB) DPB se nahaja jugovzhodno od Pohorja in se­verno od Posavskega hribovja. Recna mreža da­našnjega DPB obsega glavni vodotok Dravo, ki tece v smeri sever-severozahod-jugovzhod, ter številne manjše pritoke, ki sledijo smeri glavne­ga toka ali tecejo generalno v smeri (severo)za-hod-(jugo)vzhod. Predkvartarna podlaga DPB obsega vec razlicnih geoloških enot (sl. 1b). Za­hodno do severozahodno od DPB se nahaja Po-horje, ki je sestavljeno iz nizko, srednje do (ultra) visoko-metamorfnih kamnin Pohorskega kom­pleksa, na katere so narinjene zelo šibkometa­morfozirane kamnine Štalenskogorske serije in diskordantno odložene permo-triasne, kredne ter miocenske kamnine in sedimenti (Mioc, 1978; Hinterlechner-Ravnik, 1971, 1973, 1982; Janák et al., 2004; Janák et al., 2005; Vrabec et al., 2012). V osrednjem delu Pohorja se nahajajo pluton in subvulkanski razlicki granodioritne do tonalitne sestave, ki so bili vtisnjeni v miocenu (Zupancic, 1994a, 1994b; Altherr et al., 1995; Fodor et al., 2008; Trajanova et al., 2008; Trajanova, 2013). V strukturnem smislu predneogenske kamnine uvršcamo k Vzhodnim Alpam. Miocenske kamni­ne in sedimenti Mariborskega podbazena so se odlagali na zahodnem robu Centralne Paratetide (sistem Panonskega bazena) (Jelen & Rifelj, 2011; Trajanova, 2013). Usedanje plio-zgodnjepleisto­censki sedimentov na tem obmocju se je pricelo odlagati po koncnem umiku Centralne Parateti­de (Markic, 2009). Na snovi predhodnih podatkov so v DPB debeli do 65 m, kvartarni sedimenti pa E.MENCIN GALE, P. JAMŠEK RUPNIK, M. TRAJANOVA, L. GALE, M. BAVEC, F. S. ANSELMETTI & A. ŠMUC 1989). In a structural sense, the DPB coincides with the Ptuj-Ljutomer syncline, which is bound­ ed by the Ormož-Selnica anticline to the south (Mioc & Markovic, 1998). The later formed due to tectonic activity within the Donat fault zone. The most important faults of the latter are the dextral transpressive Donat fault and the reverse Ljutom­er fault (Fodor et al., 1998, 2002). Methods The methodology for investigating the Plio -Early Pleistocene sediments was following guidelines from Stokes et al. (2012). Field obser­vations were supported with geomorphological, sedimentological and microfacies analyses. Geo­morphological analyses itself focused not only on Plio-Early Pleistocene sedimentary bodies, but also other younger sedimentary bodies from Pli­ocene-Quaternary succession. The spatial extent of Plio-Early Pleistocene unit was constrained from Basic Geological Map, sheets Celje and Maribor (Buser, 1977; Žnidarcic & Mioc, 1988) and modified by analyzing the high -resolution digital elevation model derived from lidar data (Ministry of the Environment and Spa­tial Planning, Slovenian Environment Agency, 2011). Units mapped by means of remote sensing were field checked at the selected locations. Ge­omorphological analysis was carried out in GIS environment and encompassed analysis of topo­graphic profiles, shaded relief map, topographic contours with 1 m equidistance, slope degree and slope aspect maps. Results of analysis are pre­sented on two geomorphological maps, showing Plio-Early Pleistocene and other Quaternary ter­races and fans in the studied basins (Figs. 2, 3). Geomorphological maps present the spatial ex­tent of preserved surfaces of sedimentary bodies (surface forms). Therefore, oldest sediments are mostly occurring in greater spatial extent than their geomorphologically mapped present sur­face form (terrace or fan), i.e. the sediments at the surface occur also in the areas where their surface form is not preserved and mapped. Seven sedimentary sections were logged: in CB these were Miklavž (MI), Šešce (SE) and Griže (GR), and in DPB Nova vas (NV), Hoce (HO), Radana vas (RA) and Škalce (SKA). Clas­sification of lithofacies by Evans and Benn (2004) was used for logging. Sections height range from 1.5 to 5.5 m. Clasts from individual sections were sieved to 16-63 mm fraction. This fraction was chosen because it is appropriate for macroscopic identification of lithotypes of individual clasts, as well as for preparation of thin-sections. 30 m. V slednjih so vidne štiri terase (Mioc & Žni­darcic, 1989). DPB v strukturnem smislu sovpa­da s Ptujsko-Ljutomersko sinklinalo, na jugu pa ga omejuje Ormoško-Selniška antiklinala (Mioc & Markovic, 1998). Dviganje slednje je pogojeno z aktivnostjo Donacke prelomne cone, v kateri sta najpomembnejša potencialno aktivna desno transpresivni Donacki prelom ter reverzni Ljut­omerski prelom (Fodor et al., 1998, 2002). Metode Metodologija raziskovanja plio-zgodnjeplei­stocenskih sedimentov je sledila smernicam pov­zetih po Stokesu in sodelavcih (2012), pri cemer so bila terenska opazovanja podprta z geomor­fološkimi, sedimentološkimi in mikrofaciesnimi analizami. Sama geomorfološka analiza je poleg analize plio-zgodnjepleistocenskih sedimenta­cijskih teles zajemala tudi mlajša sedimentacij-ska telesa iz pliocensko-kvartarnega zaporedja. Prostorska razširjenost enote plio-zgodnjeplei­stocenskih sedimentov je bila ugotovljena s po­mocjo uporabe Osnovne geološke karte lista Celje in Maribor (Buser, 1977; Žnidarcic & Mioc, 1988) ter na analizi visokolocljivostnega digitalnega modela reliefa izdelanega na podlagi lidarskih podatkov (Ministrstvo za okolje in prostor, Agen­cija RS za okolje in prostor). Enote izdvojene z metodami daljinskega zaznavanja so bile na iz­branih lokacijah preverjene s terenskim delom. Geomorfološke analize so bile izvedene v GIS okolju in so obsegale analizo topografskih pro-filov in kart sencenega reliefa, izohips z ekvidi­stanco 1 m, naklonov pobocij ter usmerjenosti pobocij. Izdelani sta bili geomorfološki karti, ki prikazujeta plio-zgodnjepleistocenske in osta­le kvartarne terase in vršaje obravnavanih ba­zenov (sl. 2, 3). Geomorfološki karti prikazujeta razprostranjenost ohranjenih površin sedimen­tacijskih teles (površinske oblike). Predvsem za starejše sedimente zato velja, da je njihov obseg pojavljanja sicer vecji od kartiranega obsega nji-hove današnje površinske oblike (terase ali vrša­ja), saj se sedimenti danes nahajajo tudi tam, kjer sama površinska oblika ni ohranjena. Posnetih je bilo sedem sedimentoloških profi­lov, in sicer v CB Miklavž (MI), Šešce (SE) in Gri­že (GR) ter v DPB Nova vas (NV), Hoce (HO), Ra-dana vas (RA) in Škalce (SKA), pri cemer je bila uporabljena klasifikacija litofaciesov po Evans in Benn (2004). Dolžina profilov znaša od 1,5 do 5,5 m. Prodniki iz posamicnih profilov so bili presejani na frakcijo od 16 do 63 mm. Ta velikost je ustrezna za makroskopsko litološko dolocitev klastov in za izdelavo zbruska. Clast lithological analysis was following guidelines from Walden (2004), Lindsey et al. (2007) and Gale and Hoare (2011), adapted for the purpose of our study. 98-299 clasts were analyz­ ed per sample from CB and 173-346 clasts per sample from DPB. 53 thin sections were prepared and examined with a polarizing microscope. Clast lithological analysis is traditionally per­ formed on the macroscopic level (e.g. Bridgland et al., 2012), however, during our study it turned out that identification of weathered clasts is of­ten wrong, and that microscopic analysis of the clasts significantly increases the reliability of the results. Due to lack of data on microfacies of Tri­assic volcanic rocks in the CB area, we addition­ally sampled their outcrops in the vicinity. Results Pliocene-Quaternary sediments of the CB and DPB are preserved in alluvial terraces and fans, following the terrace staircase model, which is typical in areas affected by relative surface up­lift and erosional base lowering (e.g. Bridgland, 2000; Bridgland & Maddy, 2002; Bridgland & Westaway, 2008a; Bridgland & Westaway, 2008b; Doppler et al., 2011; van Husen & Reitner, 2011; Westaway, 2002). The oldest sediments are pre­served in the highest terraces. Pliocene-Quaternary sediments of the Celje Basin The stratigraphy of alluvial terraces and fans in the CB is shown in the profile P1 (Fig. 2B and Table 1). Based on geomorphological mapping, five Pliocene-Quaternary terrace levels were dis­tinguished (T0, T1, T3, T4, T5). Lithofacies and lithological analysis of gravels and clasts, respec­tively, were focused on Plio-Early Pleistocene sediments located on western and southern side of the basin (Fig. 2). Sediments of terrace levels T4 and T5 were analyzed in detail (Figs. 2, 4). Section MI (46,2394737°, 15,0395998°, 317 m a.s.l.) and SE (46,2307163°, 15,1398659°, 278 m a.s.l.) are located on the terrace level T4, and section GR (46,2196692°, 15,1520658°, 347 m a.s.l.) on terrace level T5. Pliocene-Quaternary sediments of the Drava-Ptuj Basin The stratigraphy of alluvial terraces and fans in the DPB is shown in profile P2 and P3 (Figs. 3B, 3C and Table 2). Six Pliocene-Quaternary terrace levels were distinguished (T0, T1, T2, T3, T4, T5). Lithofacies and lithological analysis of Za litološko analizo klastov so bile upošte- vane in prilagojene smernice avtorjev Walden (2004), Lindsey in sodelavcev (2007) ter Gale in Hoare (2011). V CB je bila litološka analiza izve­dena na 98 do 299 klastih na vzorec, v DPB pa na 173 do 346 klastih na vzorec. Izdelanih in pregle­ danih je bilo 53 zbruskov klastov; 20 v CB in 33 v DPB. Tradicionalno je litološka analiza klastov izvedena makroskopsko (npr. Bridgland et al., 2012), vendar je bilo tekom študije ugotovljeno, da so napake pri identifikaciji preperelih kamnin pogoste in da mikroskopska analiza znatno pri­ pomore k vecji zanesljivosti rezultatov. Zaradi pomanjkanja podatkov o mikrofaciesu triasnih vulkanskih kamnin na obmocju CB, so bili do-datno vzorceni tudi njihovi bližnji izdanki. Rezultati Pliocensko-kvartarni sedimenti CB in DPB so ohranjeni v terasah in vršajih, ki sledijo mo- delu inverzne terasne stratigrafije (ang. terrace staircase), ki je znacilen za obmocja relativne­ga dvigovanja površja in zniževanja erozijske baze (npr. Bridgland, 2000; Bridgland & Maddy, 2002; Bridgland & Westaway, 2008a; Bridgland & Westaway, 2008b; Doppler et al., 2011; van Hu-sen & Reitner, 2011; Westaway, 2002). Pri tem so najstarejši sedimenti ohranjeni na najvišje leže-cih terasah. Pliocensko-kvartarni sedimenti Celjskega bazena Stratigrafija teras in vršajev v CB, ugotovljena s to študijo, je prikazana na profilu P1 (sl. 2B in Tabela 1). Na podlagi geomorfološkega kartira­nja je bilo ugotovljenih pet pliocenski-kvartar­nih terasnih nivojev (T0, T1, T3, T4, T5). Litofaci­esna in litološka analiza prodov in klastov je bila osredotocena le na plio-zgodnjepleistocenske se­dimente, ki se nahajajo na zahodni in južni strani bazena (sl. 2). Sedimenti so bili podrobneje anali­zirani na terasnem nivoju T4 in T5 (sl. 2, 4). Profi-la MI (46,2394737°, 15,0395998°, 317 m n.v.) in SE (46,2307163°, 15,1398659°, 278 m n.v.) se nahajata na terasnem nivoju T4, profil GR (46,2196692°, 15,1520658°, 347 m n.v.) pa na terasnem nivoju T5. Pliocensko-kvartarni sedimenti Dravsko-Ptujskega bazena Stratigrafija teras in vršajev v DPB, ugotovlje­na s to študijo, je prikazana na profilu P2 in P3 (sl. 3B, 3C in Tabela 2) pri cemer je bilo ugotovljenih šest pliocensko-kvartarnih terasnih nivojev (T0, T1, T2, T3, T4, T5). Litofaciesna in litološka ana­ E.MENCIN GALE, P. JAMŠEK RUPNIK, M. TRAJANOVA, L. GALE, M. BAVEC, F. S. ANSELMETTI & A. ŠMUC Fig. 2. Geomorphological analysis of the Pliocene-Quaternary surfaces of the Celje Basin. (A) Geomorphological map of the Plio-Early Pleistocene, Middle Pleistocene, Late Pleistoceneand Holocene terraces and fans with locations of the studied sections marked (MI, SE, GR). (B) Topographic profi le P1 with present-day elevations of the terraces and fans. Sl. 2. Geomorfološka analiza pliocensko-kvartarnih površinskih oblik Celjskega bazena. (A) Geomorfološka karta plio-zgodnjepleistocenskih, srednjepleistocenskih, poznopleisto­ censkih in holocenskih teras in vršajev z oznacenimi lokacijami profi lov (MI, SE, GR). (B) Topografski profi l P1 z današnjimi višinami teras in vršajev. Table 1. Basic geomorphological characteristics of the terrace system in the Celje Basin. Tabela 1. Osnovne karakteristike sistema teras v Celjskem bazenu. Terrace level /Terasni nivo Elevation .m a.s.l.. /Višina .m n.v.. Height above the fl oodplain.m. /Relativna višina nadpoplavnoravnico .m. Thickness /Debelina.m.(after / poBuser,1979) Morphology of the unit / Morfologija enote Composition ofthe sediments /Sestavasedimentov Age / Starost (after / po Buser, 1979) Floodplain /Poplavnaravnica 236 - 304 / 25 Very well-preserved former channel pattern / Zelo dobro ohranjena morfologija recnihmeandrov Carbonategravel /Karbonatni prod Quaternary / Kvartar T0 238 - 309 2 - 5 Very well-preserved terrace morphology, rare and not well visible former channel meanders /Morfologija terase zelo dobro ohranjena, redki slabo ohranjeni recni meandri Quaternary / Kvartar T1 279 - 308 7 - 8 35 Well-preserved terrace morphology, however the terrace surfaces are smaller and presentonly in a few places within the basin / Morfologija terase dobro ohranjena vendar terase nezavzemajo velikih površin in so prisotne le na nekaj mestih znotraj bazena Identifi ed as single“Plio-Quaternary”terrace / Identifi ciranokot enotna»pliokvartarna« terasa T3 245 - 324 9 - 14 Well-preserved terrace and fan morphology, present at basin boundaries /Morfologija teras in vršajev dobro ohranjena, prisotnost ob robovih bazena T4 258 - 338 15 - 22 Terrace and fan erosional remnants with degraded morphology incised by the drainagenetwork / Morfologija teras in vršajev degradirana – erozijski ostanki teras, pogosto vrezo­vanje manjših potokov Non-carbonategravel /Nekarbonatni prod T5 262 - 366 42 - 124 Table 2. Basic geomorphological characteristics of the terrace system in the Drava-Ptuj Basin. Tabela 2. Osnovne znacilnosti sistema teras v Dravsko-Ptujskem bazenu. Terrace level /Terasni nivo Elevation .m a.s.l.. /Višina .m n.v.. Height above the fl oodplain.m. /Relativna višina nadpoplavnoravnico .m. Thickness /Debelina.m.(after / poBuser,1979) Morphology of the unit / Morfologija enote Composition ofthe sediments /Sestavasedimentov Age / Starost (after / po Mioc &Žnidarcic, 1989) Floodplain /Poplavnaravnica 216 - 266 / up to 30 m /do 30 m Very well-preserved former channel pattern / Zelo dobro ohranjena morfologija recnihmeandrov Carbonategravel /Karbonatni prod Quaternary / Kvartar T0 224 - 284 7 Well-preserved former channel pattern, very well-preserved terrace morphology /Dobro ohranjena morfologija recnih meandrov, morfologija terase zelo dobro ohranjena Quaternary / Kvartar T1 228 - 288 9 - 12 Moderately-preserved former channel pattern, very well-preserved terrace morphology /Srednje dobro ohranjena morfologija recnih meandrov, morfologija terase zelo dobroohranjena Quaternary / Kvartar T2 232 - 278 13 - 14 Very well-preserved terrace morphology / Morfologija terase zelo dobro ohranjena Quaternary / Kvartar T3 251 - 333 15 - 23 25 - 40 Well-preserved terrace and fan morphology, but the terrace surfaces are present only in afew places within the basin / Morfologija teras in vršajev dobro ohranjena, vendar teraseohranjene le na nekaj mestih znotraj bazena Identifi ed as single“Plio-Quaternary”terrace / Identifi cirano kotenotna »pliokvartarna«terasa T4 231 - 437 15 - 50 Terrace and fan remnants with degraded morphology incised by the drainage network /Morfologija teras in vršajev degradirana – ostanki teras, pogosto vrezovanje manjšihpotokov T5 277 - 450 40 - 100 E.MENCIN GALE, P. JAMŠEK RUPNIK, M. TRAJANOVA, L. GALE, M. BAVEC, F. S. ANSELMETTI & A. ŠMUC Fig. 3. Geomorphological analysis of the Pliocene-Quaternary surfaces of the Drava-Ptuj Basin. (A) Geomorphological map of the Plio-Early Pleistocene, Middle Pleistocene, Late Pleistocene and Holocene terraces and fans with locations of the studied sections marked (NV, HO, RA, SKA). (B, C) Topographic profiles P2 and P3, with present-day elevations of the terraces and fans. Sl. 3. Geomorfološka analiza pliocensko-kvartarnih površinskih oblik Dravsko-Ptujskega bazena. (A) Geomorfološka karta plio-zgodnjepleistocenskih, srednjepleistocenskih, poznopleistocenskih in holocenskih teras in vršajev z oznacenimi lokaci­jami profilov (NV, HO, RA, SKA). (B, C) Topografska profila P2 in P3 z današnjimi višinami teras in vršajev. gravels and clasts, respectively, were focused on Plio-Early Pleistocene sediments of terrace level T4 in sections NV (46.532506°, 15.615964°, 293 m a.s.l.) and HO (46.495161°, 15.626824°, 319 m a.s.l.), and sediments of terrace level T5 in sections SKA (46,3627381°, 15,416756°, 404 m a.s.l.) and RA (46,3691538°, 15,4047645°, 389 m a.s.l.). liza prodov in klastov je bila osredotocena na pli-o-zgodnjepleistocenske sedimente na terasnem nivoju T4 v profilih NV (46.532506°, 15.615964°, 293 m n.v.) in HO (46.495161°, 15.626824°, 319 m n.v.) ter sedimente na terasnem nivoju T5 na loka­cijah SKA (46,3627381°, 15,416756°, 404 m n.v.) in RA (46,3691538°, 15,4047645°, 389 m n.v.). Fig. 4. Lithofacies of the Plio-Early Pleistocene sediments of the Celje Basin in sections Šešce (SE), Miklavž (MI) and Griže (GR). White stars indicate the parts of the sections presented in the photographs. Sl. 4. Litofaciesi plio-zgodnjepleistocenskih sedimentov Celjskega bazena v profilih Šešce (SE), Miklavž (MI) in Griže (GR). Bele zvezde oznacujejo fotografirane dele profilov. Lithofacies analysis of the sections and clast lithological analysis In seven sections, eight different gravely, sandy and muddy lithofacies were recognized (Table 3). Contacts between the layers are gradu­al or in parts erosional. The thickness of the lay­ers varies laterally and reach values from a few centimeters to approximately two meters. The sediments partly occur in lenses. Cross-lamina­tion is present in some of the sandy layers and coalified plant fragments up to a few centimeters in size are present in fine-grained layers. Litofaciesna analiza profilov in litološka analiza klastov V skupno sedmih profilih je bilo ugotovljenih osem razlicnih litofaciesov (Tabela 3). Prisotni so prodnati, pešceni in muljasti sedimenti. Kontakti med posameznimi litofaciesi so postopni, mesto-ma tudi erozijski. Debelina plasti variira od nekaj centimetrov do približno dva metra ter se lateral-no spreminja. Sedimenti se ponekod pojavljajo v lecah. Mestoma se v pešcenih plasteh pojavlja navzkrižna plastnatost. Ponekod so bili v drob­nozrnatih plasteh najdeni poogleneli fragmenti kopenskih rastlin veliki do nekaj centimetrov. E.MENCIN GALE, P. JAMŠEK RUPNIK, M. TRAJANOVA, L. GALE, M. BAVEC, F. S. ANSELMETTI & A. ŠMUC Fig. 5. Lithofacies of the Plio-Early Pleistocene sediments of the Drava-Ptuj Basin in sections Nova vas (NV), Hoce (HO), Škalce (SKA) and Radnana vas (RA). White stars indicate the parts of the sections presented in the photographs. Sl. 5. Litofaciesi plio-zgodnjepleistocenskih sedimentov Dravsko-Ptujskega bazena v profilih Nova vas (NV), Hoce (HO), Škalce (SKA) in Radnana vas (RA). Bele zvezde oznacujejo fotografirane dele profilov. The results of the clast lithological analysis are presented in tables 4 and 5 and on figures 6 and 7. In the CB, clasts of metamorphic, volcanic, volcaniclastic and clastic rocks occur, whereas in the DPB, metamorphic, volcanic, volcaniclastic and carbonate clasts are present (Fig. 8). Rezultati litološke analize klastov so predsta­vljeni v tabelah 4 in 5 ter na slikah 6 in 7. Sli­ka 8 podaja primerjavo litoloških analiz klastov obeh bazenov. V CB prevladujejo metamorfne, vulkanske in vulkanoklastcne ter klasticne ka­mnine, v DPB pa metamorfne, vulkanske in vul­kanoklasticne ter karbonatne kamnine. Table 3. Lithofacies codes and descriptions, interpretation of depositional setting and occurrences within the sections. Tabela 3. Okrajšave in opisi litofaciesov, interpretacija sedimentacijskega okolja in pojavnost v profi lih. Litofacies code and defi nition / Okrajšava in defi nicija litofaciesa(Evans & Benn, 2004) Additional lithofacies description /Dodaten opis litofaciesa Interpretation / Interpretacija Occurrence inthe sections /Pojavnost vprofi lih Bcm Clast-supported gravel (bolders), massive /Prod (balvani) s prevladujocimiklasti, masiven Well-sorted gravel, well-rounded clasts /Dobro sortiran prod, klasti dobro zaobljeni Channel lag deposits and gravel (gravely-sandy) dunes;coarse-grained sediments in alluvial fans /Sedimenti korita in prodnate (prodnato-pešcene) sipine;grobozrnati sedimenti v aluvialnih pahljacah RA, SE Gm Clast-supported gravel, massive /Prod s prevladujocimi klasti, masiven Sub- to well-rounded clasts, gravellocally highly weathered /Slabo do dobro zaobljeni klasti, v posameznih profi lih prod mocno preperel NV, HO, SKA,RA, SE, MI Gms Matrix-supported gravel, massive /Prod s prevladujoco osnovo, masiven Poorly- to moderately-sorted, angular towell-rounded clasts, locally highly weathered /Slabo do srednje sortiran prod, oglati do dobrozaobljeni klasti, mestoma mocno prepereli NV, MI, GR Sm Sand, massive / Pesek, masiven In parts marmorized and pedogenized /Mestoma marmoriziran in pedogeniziran Sand dunes /Pešcene sipine NV, SKA, RA,SE Sm(d) Sand, massive, with dropstones /Pesek, masiven, s posameznimi prodniki In parts marmorized, sub-angular to well-rounded clasts /Mestoma marmoriziran, klasti pol-oglatido dobro zaobljeni RA, MI Sp Sand, cross-bedded /Pesek, navzkrižno plastnat / SKA Fm Fines (silt and clay), massive /Drobnozrnati sedimenti(melj in glina), masivni In parts marmorized and pedogenizedwith plant remains /Mestoma marmoriziran in pedogeniziranz rastlinskimi ostanki Floodplain sediments and fi negrained sedimentsin alluvial fans / Sedimenti poplavne ravnice in drobnozrnati sedimenti valuvialnih pahljacah HO, SE, MI Fm(d) Fines (silt and clay), massivewith dropstones /Drobnozrnati sedimenti (melj in glina),masivni, s posameznimi prodniki In parts marmorized and pedogenized;clasts sub- to well-rounded /Mestoma marmoriziran in pedogeniziran;klasti slabo do dobro zaobljeni NV Table 4. Microfacies of clasts of Plio-Early Pleistocene sediments and interpretation of the provenance in the Celje Basin. The term keratophyre was used in the Basic geological map(Buser, 1979; Premru, 1983). Although the term is outdated, we herein retain it, since the provenance analysis is based on the Basic geological map. Tabela 4. Mikrofacies prodnikov plio-zgodnjepleistocenskih sedimentov in interpretacija provenience v Celjskem bazenu. Izraz keratofi r je povzet po terminologiji Osnovne geološkekarte (Buser, 1979; Premru, 1983). Ker primerjava provenience klastov temelji na Osnovni geološki karti, smo izraz obdržali kljub zastarelosti. Lithogroup /Lito-skupina Lithotype / Litotip General description / Splošni opis Provenance interpretation /Interpretacija provenience Key feature for provenanceinterpretation /Kljucna lastnost zadolocitev provenience Metamorphicrocks /Metamorfnekamnine Phyllitoid micaschist /Filitoidni sljudnatskrilavec The rock consists of sparse lenticular augen of perthitic feldspar and quartz.Quartz and white mica are the main constituents. Very frequent are opaque mine­rals (mostly secondary) concentrated along foliation and cleavage. Tourmaline issparsely present. / Kamnina vsebuje redka lecasta ocesa perthitnega glinenca inkremena. Prevladujejo kremen in minerali sljud. Zelo pogosti so neprosojni mine-rali (vecinoma sekundarnega izvora), ki so koncentrirani vzdolž foliacije in kliva­ža. Redek je turmalin. Source rocks eroded (similarfacies outcrop on the S Pohorjearea (Hudinja stream drainage) /Izvorne kamnine erodirane(podobni faciesi izdanjajo naobmocju J Pohorja – potokHudinja) Metamorphic degree and facies /Stopnja metamorfozein facies Volcanic andvolcaniclasticrocks / Vulkanske invulkanoklasticnekamnine Keratophyre /Keratofi r The rock consists of glassy groundmass and phenocrysts of albitized plagioclasesand biotite. Volcanic glass is altered to microcrystalline quartz, chlorite, sericiteand locally calcite. / Kamnina vsebuje steklasto osnovo z vtrošniki albitiziranihplagioklazov, alkalnih glinencev, kremena, plagioklazov in biotita. Vulkanskosteklo je spremenjeno v mikrokristalen kremen, albit, klorit, sericit in mestomakalcit. Triassic volcanic andvolcanoclastic rocks(N, W and S slopes of the CB) /Triasne vulkanske invulkanoklasticne kamnine(S, Z in J pobocja CB) Visible diagenesis, compacttexture of the rock, typicalmineral alteration /Vidni znaki diageneze,kompaktna strukturakamnine, znacilnespremembe v mineralizaciji Fine- to coarse-grained tuff /Drobno dodebelo-zrnati tuf The rock consists of tuffaceous matrix altered to microcrystalline quartz, chlorite,sericite, muscovite, epidote and albite(?). It contains crystal grains of quartz, felds­pars, oxidized mafi c minerals, volcanic rock fragments and rare lapilli. / Kamnina je sestavljena iz tufske osnove, ki je spremenjena v mikrokristalen kremen, klorit,sericit, muskovit, epidot in albit(?). Vsebuje kristaloklaste kremena, glinencevin oksidiranih mafi cnih mineralov ter vulkanske liticne drobce in redke lapile.Kamnina je pogosto mocno preperela. Fine-grainedvitric tuff /Drobno zrnativitricni tuf The rock consists of fi ne-grained tuffaceous matrix and glass shards of crystalgrains. Volcanic glass is altered to microcrystalline quartz, phyllosilicate mineralsand zeolites(?). Crystal grains belong to feldspars and subordinately quartz. Rarebiotite is chloritized. / Kamnina vsebuje drobnozrnato tufsko osnovo in košckestekla. Vulkansko steklo je spremenjeno v mikrokristalen kremen, fi losilikatneminerale in zeolite(?). Kristalna zrna pripadajo glinencem in v manjši meri kreme-nu. Redek biotit je kloritiziran. Oligocene Smrekovec series(wider area N and W from the CB)/Oligocenska Smrekovška serija(širše obmocje S in Z od CB) Rock texture (withoutindicators of diagenesis),presence of glass shards /Struktura kamnine(ni znakov diageneze),dacitna sestava, vidnecrepinjice stekla.(Kralj, 2016a, Kralj, 2016b) Clastic rocks /Klasticnekamnine Siltstoneto slate /Meljevec doskrilavi glinavec The main constituents are white micas uniformly aligned along slaty cleavage.Sparse biotite is present. Sericite-chlorite aggregates are aligned transverse toslaty cleavage. The rock is strongly hydroscopic and impregnated by limoniticpigment. / Kamnina ima izrazito poudarjeno usmerjeno teksturo. Prevladuje belasljuda, ki je orientirana vzdolž skrilave teksture. Redek je biotit. Sericitno-kloritniagregati so orientirani pravokotno na usmerjeno teksturo. Kamnina je mocnohigroskopicna in impregnirana z limonitnim pigmentom. Carboniferous (S slopes of the CB) /Karbon (J obronki CB) Structure, texture,metamorphic degreeand facies /Tekstura, struktura,stopnja metamorfozein facies Very weaklymetamorphosed quartz sandstone /Zelo nizkometamorforizirankremenovpešcenjak The rock contains quartz, rare fragments of lithic grains (slate) and rare musco­vite. Accessory minerals are opaque minerals, and rare rutile, tourmaline andzircon. Quartz-sericite matrix is recrystallized, often with directed growth and isintergrown with quartz grains on the rims. Anastomosing slaty cleavage developedwith concentrations of opaque non-migrative component. / Kamnino sestavlja­jo kremen, redki odlomki liticnih zrn (glinastega skrilavca) in redek muskovit.Akcesorni so neprosojni minerali ter redek rutil, turmalin in cirkon. Kremenovo­sericitno vezivo je rekristalizirano, pogosto usmerjeno rašceno in se obodno pre­rašca s kremenovimi klasti. Med klasti je nastal povijajoc klivaž, v katerem jekoncentrirana nemigrativna neprosojna komponenta. Carboniferous (S slopes of the CB) /Karbon (J obronki CB) Metamorphic degreeand facies /Stopnja metamorfozein facies E.MENCIN GALE, P. JAMŠEK RUPNIK, M. TRAJANOVA, L. GALE, M. BAVEC, F. S. ANSELMETTI & A. ŠMUC Table 5. Microfacies of clasts of Plio-Early Pleistocene sediments and interpretation of the provenance in the Drava-Ptuj Basin. The term keratophyre was used in the Basic geologicalmap (Buser, 1979; Premru, 1983) and is for this reason retained, despite being outdated. Tabela 5. Mikrofacies prodnikov plio-zgodnjepleistocenskih sedimentov in interpretacija provenience v Dravsko-Ptujskem bazenu. Izraz keratofi r je povzet po terminologiji Osnovnegeološke karte (Buser, 1979; Premru, 1983). Ker primerjava provenience klastov temelji na Osnovni geološki karti, smo izraz kljub zastarelosti obdržali. Lithogroup /Lito-skupina Lithotype / Litotip General description / Splošni opis Provenance interpretation /Interpretacija provenience Key feature for provenanceinterpretation /Kljucna lastnost zadolocitev provenience Metamorphicrocks /Metamorfnekamnine Amfibolitnaskupina (epidotno amfi bolski skrilavcido amfi boliti) / Amphiboliticgroup (epidote amphibole schists toamphibolites) The rock consists of hornblend, epidote, clinozoisite, chlorite, feldspar and quartz(in some of the samples). Accessory minerals are rutile, titanite and opaque min­erals. Some of the samples have pronounced foliation, others pronounced por­phyroclastic texture. / Kamnina je sestavljena iz rogovace, epidota, klinozoisita,kloria, redko glinenca in kremena (v nekaterih vzorcih). Akcesorni so rutil, titanitin neprosojni minerali. Nekateri vzorci imajo izraženo foliacijo, drugi pa izrazito porfi roklasticno strukturo. Pohorje and Kozjak(W and N from the DPB) /Vzhodne Alpe - Pohorje inKozjak (Z in S od DPB) Typical facies of the Pohorjemetamorphic complex /Znacilen facies pohorskegametamorfnega kompleksa(Hinterlechner Ravnik 1971,1973) Mica schists /Blestniki inmuskovitni skrilavci The rock consists of muscovite, quartz, garnet (mostly its relicts), chlorite, rare bi-otite (in parts chloritized), zoisite/clinozoisite, traces of accessory zircon, titanite,rutile, and opaque minerals). Schistose structure with pronounced foliation is pre­sent. / Kamnino sestavljajo muskovit, kremen, granati (vecinoma njihovi relikti),klorit, redek biotit (mestoma kloritiziran), zoisit/klinozoisit, sledovi akcesornihmineralov cirkona, titanita, rutila in neprosojnih mineralov. Tekstura je skrilava zizrazito foliacijo. Nekateri vzorci so mocno prepereli. Eastern Alps (Pohorjeand Kozjak area, also thesurroundings of Ravne naKoroškem) (most probablyeastern Pohorje and northof Maribor) / Vzhodne Alpe(najverjetneje vzhodno Pohorjein severno od Maribora) Typical facies /Znacilen facies Slate /Glinast skrilavec Macroscopic texture seems massive. Microscopically, the rock has pronouncedcleavage, expressed as preferred orientated sericite and chlorite. In-between themare grains of clastic quartz, feldspar, infrequent opaque minerals of primaryand secondary origin, tourmaline, traces of zircon, apatite and epidote(?). Somesericite-chlorite aggregates and larger white mica fl akes are oriented transverseto foliation. / Makroskopsko je kamnina videti masivna. Mikroskopsko je mocnoizražen klivaž poudarjen z usmerjenimi listki sericita in klorita. Vmes so zrnakremena, glinencev, redkih neprosojnih mineralov (primarnega in sekundarnegaizvora), turmalina, sledovi cirkona, apatita in epidota(?). Posamezni sericitno-klo­ritni agregati in vecji listki sljud so usmerjeni precno na foliacijo. Štalenskogorska serija(Z Kozjak in/ali SZ del Pohorja)/ Magdalensberg series(W Kozjak and/or NW part ofthe Pohorje area) Typical facies /Znacilen facies Quartzite ofvery low-grademetamorphism / Kvarcit zelo nizkestopnje metamorfoze The rock contains of mineral clasts of quartz, tourmaline, opaque minerals rutile,titanite and zircon. It contains infrequent lithic grains of slate and phylite. Quartzgrains have undulose extinction and serrated grain boundaries with small quanti­ty of recrystallized matrix in between. The source rock of the quartzite represents”dirty” quartz sandstone presumably formed from Carboniferous clastic rocksfrom the zone of stronger dynamometamorphism. / Kamnina je sestavljena iz mi-neralnih klastov kremena, turmalina, neprosojnih mineralov, rutila, titanita incirkona. Redka so liticna zrna glinastega skrilavca in fi lita. Zrna kremena valovi-to potemnijo in se pogosto zobcasto prerašcajo med seboj in z vmesnim vezivom.Kvarcit nastal iz necistega kremenovega pešcenjaka v coni mocnejših dinamome­tamorfnih sprememb, predvidoma nastal iz karbonskih klastitov. Carboniferous (Dravinjadrainage, S from SlovenskeKonjice) /Karbon (drenaža Dravinje,J od Slovenskih Konjic) Typical facies /Znacilen facies Volcanic andvolcaniclasticrocks /Vulkanske invulkanoklasticnekamnine Keratophyre /Keratofi r The rock is extensively altered. The former glassy groundmass is altered to micro-crystalline quartz and phyllosilicate minerals. Phenocrysts of feldspars and mafi cminerals can only be anticipated by shape remains. The rock is impregnated withFe-oxides and hydroxides. / Kamnina je mocno spremenjena. Nekdanja steklenaosnova je spremenjena v mikrokristalen kremen in fi losilikate. Oblika popolnomapreperelih vtrošnikov nakazuje na glinence in mafi cne minerale. Kamnina je po­polnoma oksidirana, impregnirana z železovimi oksidi in hidroksidi. The rock does not outcrops inthe today‘s drainage area of thesampling locality SKA (lack ofdetail geological map oreroded outcrops?) /Triasne vulkanske invulkanoklasticne kamnine.Kamnina ne izdanja vdanašnjem drenažnem obmocjuvzorcne lokacije SKA (manjkanatancna geološka karta alipa so izdanki popolnomaerodirani) Visible diagenesis, compacttexture of the rock, typicalmineral alteration /Vidni znaki diageneze,kompaktna strukturakamnine, znacilnespremembe v mineralizaciji. Keratophyre tuff /Keratofi rski tuf The rock consists of fragments of altered feldspars, biotite and volcanic lithic fra­gments. The matrix is altered to microcrystalline quartz, Fe-oxides and kaolinite.Some of the samples contain welded glass shards. / Kamnino sestavljajo fragmentispremenjenih glinencev, biotita in vulkanskih liticnih drobcev. Osnova je spreme­njena v mikrokristalen kremen, železove okside in kaolinit. Nekateri vzorci vsebu­jejo nataljene crepinjice stekla. E.MENCIN GALE, P. JAMŠEK RUPNIK, M. TRAJANOVA, L. GALE, M. BAVEC, F. S. ANSELMETTI & A. ŠMUC Carbonaterocks / Karbonatnekamnine Limestone breccia /Apnenceva breca Polimiktna apnenceva breca (Tubiphytes obscurus Maslov, Calcitornella/ Tuberitina, Schwagerinidae, Epimastopora sp., Anthracoporella spectabilisPia); klasti apnenca in pešcenjaka, v vezivu tudi fuzulinide / Polymict limestonebreccia (Tubiphytes obscurus Maslov, Calcitornella/Tuberitina, Schwagerinidae, Epimastopora sp. , Anthracoporella spectabilis Pia); limestone and sandstoneclasts, isolated fusulinid foraminifera Lower Permian breccia:Dovžanova soteska andTrogkofel Formations(west of the DPB; the area ofSlovenske Konjice) /Spodnjepermska breca:Dovžanosoteška in Trogkofelskaformacija (zahodno od DPB;okolica Slovenskih Konjic) Tubiphytes-like microproblematica / Tubifi tna mikroproblematika(Tubiphytes obscurusMaslov),foraminifera / foraminifere(Calcitornella/Tuberitina,Schwagerinidae),algae /alge (Epimastoporasp. in Anthracoporellaspectabilis Pia) Marly limestone /Laporast apnenec Bioclastic wackstone with terregenous admixture /Bioklasticni wackstone s terigeno primesjo Upper Permian or LowerTriassic limestone /Zgornjepermski alispodnjetriasni apnenec / Micritic limestone / Mikritni apnenci Mudstone with dessication voids, intraclastic wackstone and calcimicrobialboundstone (with foraminifera Endotriadella or Ammobaculites, ”Trochammina”sp.), bioclastic wackstone and packstone (Agathammina sp., Aulotortus ex gr. sinuosus Weynschenk, ?Aulotortus friedli (Kristan-Tollmann)). / Mudstone z izsu­šitvenimi porami, intraklasticni wackstone in kalcimikrobni boundstone (s fora­miniferami Endotriadella ali Ammobaculites, »Trochammina« sp.,), bioklasticniwackstone in packstone (s foraminiferami Agathammina sp., Aulotortus ex gr. sinuosus Weynschenk, ?Aulotortus friedli (Kristan-Tollmann)) Ladinian to lower Carnianshallow marine facies /Ladinijski do spodnjekarnijskiplitvomorski faciesi foraminifera / foraminifere»Trochammina« sp., ?Variostoma pralongenseKristan-Tollmann,Aulotortus ex gr. sinuosusWeynschenk, ?Aulotortus friedli (Kristan-Tollmann); microproblematica / mikroproblematika(Tubiphytes obscurusMaslov) Calcarenite /Kalkarenit Bioclastic-intraclastic grainstone (foraminifera Glomospira sp., Reophax sp., ?Variostoma pralongense Kristan-Tollmann, microproblematica Tubiphytes obs-curus Maslov) / Bioklasticni-intraklasticni grainstone (foraminifere Glomospirasp., Reophax sp., ?Variostoma pralongense Kristan-Tollmann, mikroproblematikaTubiphytes obscurus Maslov) Partly recrystallizedlimestone / Delno rekristaliziranapnenec Bioclastic packstone or wackstone / Bioklasticni packstone ali wackstone Dolomite / Dolomit Crystalline dolomite / Kristalinicni dolomit Micritic limestone /Mikritni apnenec Radiolarian wackstone, radiolarian-fi lament wackstone /Radiolarijski wackstone, radiolarijski-fi lamentni wackstone Middle to Upper Triassic(alternatively Jurassic orCretaceous?) open marine facies /Srednje- do zgornjetriasni(ali jurski in kredni?)odprtomorski faciesi Radiolarians and/or thin-shelled bivalves /Radiolariji in/alitankolupinaste školjke Calcarenite /Kalkarenit Intraclastic grainstone (resediment?) / Intraklasticni grainstone (resediment?) Partly recrystallizedlimestone / Delno rekristaliziranapnenec Peloid fi lament grainstone / Peloidni fi lamentni packstone Limestone breccia /Apnenceva breca Intraclastic rudstone / Intraklasticni rudstone Calcarenite /Kalkarenit Oolithic grainstone / Ooidni grainstone Mesozoic oolithic limestones /Mezozojski ooidni apnenci / Calcarenite /Kalkarenit Rudist packstone and bioclastic packstone (Cuneolina?, Moncharmontia) / Rudistni packstone in bioklasticni packstone (Cuneolina?, Moncharmontia) Upper Cretaceous shallow waterrudist limestone fromGossau group (W of the PB;the area of Zrece) /Zgornjekredni plitvomorskirudistni apnenec Gossauskegrupe (Z od DPB; okolica Zrec) rudist fragments, foraminifera /Fragmenti rudistnih školjk,foraminifere(Cuneolina?, Moncharmontia) Fig. 6. Microfacies of the clasts in the Plio-Early Pleistocene sediments in the Celje Basin. (A) Slate with quartz and white mica as the main constituents. Rare quartz porphyroblasts are characteristic. (B) Foliated siltstone to shale with uniform preferred orientation of white mica forming continuous cleavage. (C) Fine-grained vitric (dacitic) tuff from the Oligocene Smrekovec series. (D) Glassy volcanic lithic fragment with perlitic texture in the sample of keratophyre lapilli tuff (Triassic). Some of the feldspars are extremely altered. (E) Coarse-grained (meta)tuff with incipient clevage marked with red arrow (Triassic). (F)Fine-grained tuff (Triassic). (G) Weathered (oxidized) biotite phenocryst in glassy groundmass altered to chlorite and mi-crocrystalline quartz in keratophyre (Triassic). (H) Low-grade metamorphic heterogranular quartz sandstone. (I) Authigenic growth of tourmaline in the sample of slightly metamorphosed quartz sandstone. Abbreviations: Qtz – quartz, Ms - muscovite, CG – crystal grains, y-GS – y-shaped glass shards, VRF – volcanic lithic fragment, Fsp – feldspar, M – tuffaceous matrix, Bt – biotite, g – glassy groundmass, RF – rock fragment, Tur – tourmaline, Tur(a) -authigenic tourmaline. Sl. 6. Mikrofaciesi klastov plio-zgodnjepleistocenskih sedimentov v Celjskem bazenu. (A) Filitoidni sljudnat skrilavec (pe- šceni metameljevec); v sestavi prevladujetakremen in muskovit. Znacilni so redki porfiroklasti kremena. (B) Skrilav meljevec do glinavec s prednostno orientacijo mineralov belih sljud, ki oblikujejo kontinuiran klivaž – predvidena starost: karbon. (C) Drobnozrnat vitricni (dacitni) tuf iz Smrekovške serije oligocenske starosti. (D) Steklen vulkanski liticni drobec s perlitno strukturo v vzorcu keratofirskega lapilnega tufa (trias). Nekateri K-glinenci so popolnoma prepereli. (E) Debelozrnati (meta) tuf z neizrazitim klivažem oznacenim z rdeco pušcico (trias). (F) Drobnozrnati tuf (trias). (G) Preperel (oksidiran) vtrošnik biotita v steklasti osnovi, ki je spremenjena po kloritu in mikrokristalnem kremenu v keratofirju (trias). (H) Šibko metamorfo­riziran heterozrnat kremenov pešcenjak. (I) Avtigena rast turmalina v neznatno metamorfoziranem heterozrnatem kremeno­vem pešcenjaku. Okrajšave: Qtz – kremen, Ms - muskovit, CG – kristalna zrna, y-GS – crepinjice vulkanskega stekla y oblike, VRF – vulkanski liticni drobec, Fsp – K-glinenec, M – tufska osnova, Bt – biotit, g – steklena osnova, RF – liticni drobec, Tur - turmalin, Tur(a) -avtigeni turmalin. Discussion Diskusija Sedimentary environment and Okolje sedimentacije in morfostratigrafija morphostratigraphy Pliocensko-kvartarni sedimenti so se na ob- Pliocene-Quaternary sediments of the CB and mocju CB in DPB odlagali v aluvialnemokolju, DPB were deposited in alluvial environment, kar je razvidno iz facielne analize profilov (sl. 4, as indicated by lithofacies analysis of sections 5 in Tabela 3) in geomorfološke analize sedimen-(Figs. 4, 5 and Table 3) and geomorphological tacijskih teles (sl. 2, 3). Na podlagi rezultatov se-analysis of sedimentary bodies (Figs. 2 , 3). Based dimentološke in geomorfološke analize interpre-on the results of sedimentological and geomor-tiramo, da so bili na obmocju CB vzorceni recni E.MENCIN GALE, P. JAMŠEK RUPNIK, M. TRAJANOVA, L. GALE, M. BAVEC, F. S. ANSELMETTI & A. ŠMUC Fig. 7. Microfacies of the clasts in the Plio-Early Pleistocene sediments in the Drava-Ptuj Basin. (A) Lenticular and streched blasts of hornblende oriented along foliation plains in medium- to coarse-grained amphibolite. (B) Deformational lamellae in porphyroclast of hornblende embedded in fine-grained hornblende, plagioclase, epidote, quartz and opaque minerals in epido­te amphibole schist. (C) Disintegrated and chloritized garnet surrounded by muscovite and some quartz in retrograde altered (mylonitized) mica schist. (D) Sericite-chlorite aggregates oriented transverselyl to anastomosing cleavage in slate. (E) Altered glassy keratophyre (Triassic). (F) Elongated collapsed lapilli in the sample of welded keratophyre tuff (Triassic). (G) Undulose extinction of quartz in the sample of low-grade metamorphic quartz sandstone. (H) Fragment of foraminifera Cuneolina sp. in rudist packstone (Upper Cretaceous). (I) Foraminifera of the family Schwagerinidae (Paraschwagerina? sp.) in the intergranular space in breccia (lower Permian). (J) Alga Anthracoporella spectabilis Pia in a breccia clast (lower Permian). (K) Foraminifera Cuneolina (marked with the arrowhead) and undetermined foraminifera in bioclastic packstone (Upper Cretaceous). (L) Foraminifera Moncharmontia sp. in bioclastic packstone (Upper Cretaceous). Abbreviations: Qtz – quartz, Qtz(m) – microc­rystalline quartz, Hbl – hornblende, Ep – epidote, Grt – garnet, Ms – muscovite, Ser – sericite, Chl – chlorite, Chl(a) – altered chlorite, Op – opaque mineral, WGS – welded glass shards, CL – collapsed lapilli. Sl. 7. Mikrofaciesi klastov plio-zgodnjepleistocenskih sedimentov v Dravsko-Ptujskem bazenu. (A) Lecasti blasti rogovace in vlaknata rogovaca vzdolž foliacije v srednje do debelozrnatem amfibolitu. (B) Deformacijske lamele v porfiroklastu rogovace obdane z drobno rogovaco, plagioklazom, epidotom, kremenom in neprosojnimi minerali v vzorcu epidotno amfibolskega skri­lavca. (C) Zdrobljen in kloritiziran granat obdan z muskovitom in malo kremena v vzorcu retrogradno spremenjenega (miloni­ tiziranega) blestnika. (D) Sericitno-kloritni agregati orientirani pravokotno na povijajoci klivaž v vzorcu glinastega skrilavca. (E) Preperel steklast keratofir (trias). (F) Mocno razpotegnjen lapil s porušeno strukturo v vzorcu nataljenega keratofirskega tufa (trias). (G) Valovita potemnitev kremena v šibko metamorfoziranemu kremenovemu pešcenjaku (H) Fragment foramini­fere Cuneolina sp. v rudistnem packstone-u (zgornja kreda). (I) Foraminifere družine Schwagerinidae (Paraschwagerina? sp.) v vezivu brece (spodnji perm). (J) Alga Anthracoporella spectabilis Pia v klastu znotraj apnenceve brece (spodnji perm). (K) Foraminifera Cuneolina (oznacena velika hišica na levi) in številne druge nedolocene vrste v bioklasticnem packstone-u (zgornja kreda). (L) Foraminifera rodu Moncharmontia v bioklasticnem packstone-u (zgornja kreda). Okrajšave: Qtz – kremen, Qtz(m) – mikrokristalen kremen, Hbl – rogovaca, Ep – epidot, Grt – granat, Ms – muskovit, Ser – sericit, Chl – klorit, Chl(a) – preperel klorit, Op – neprosojni mineral, WGS – nataljene crepinjice stekla, CL – lapil s porušeno strukturo. Fig. 8. Comparison of the clast lithological analysis of the Plio-Early Pleistocene sediments in the Celje (CB) and Drava-Ptuj Basin (DPB). Lithogroups correspond to those in tables 4 and 5. Sl. 8. Primerjava litološke analize klastov plio-zgodnjepleistocenskih sedimentov v Celjskem (CB) in Dravsko-Ptujskem ba­zenu (DPB) pri cemer lito-skupine kamnin ustrezajo skupinam v tabelah 4 in 5. phological analyses, we interpret sediments from CB (sections GR, SE, MI) as river sediments and from DPB as river sediments (sections RA and SKA) and alluvial fan sediments (sections NV and HO). Lithofacies Bcm, Gm and Gms were de­posited in river channels and alluvial fans. Sandy lithofacies Sm, Sm(d) and Sp are present in sand dunes, while the finest sediments Fm and Fm(d) are floodplain sediments and fine-grained part of alluvial fans. Coarse-grained and poorly sorted facies with subangular to well-rounded clasts suggest relatively short transport, which agrees with the results of clast provenance analysis (see the following section of the discussion). Alluvial sediments in CB and DPB were depos­iting simultaneously with the erosional base low­ering and relative surface uplifting, as suggest­ed by the inverse terrace staircase (Fig. 9). The floodplain surface (PR) in CB and DPB has well visible morphology with abandoned river me­anders that are very well preserved indicating braided river system active prior to regulation of Savinja and Drava river channels. The esti­mated age of this floodplain deposits is Holocene. The age of higher terrace levels was interpreted based on traditional morphostratigraphy (Buser, 1979; Mioc & Žnidarcic, 1989), comparison with other basins in the region (e.g.: Krško Basin: Ver­bic, 2004; Velenje Basin: Drobne, 1967, and Rako­vec, 1968; Ljubljana Basin: Pavich & Vidic, 1993) and on new observations from this study. Low-level terrace group encompasses terrac­ es T0 and T1 in CB and terraces T0, T1 and T2 in DPB, which are up to 8 m above the floodplain in sedimenti (profili GR, SE, MI), na obmocju DPB pa recni sedimenti (profila RA in SKA) ter sedi­menti aluvialnih pahljac (profila NV in HO). Li-tofaciesi Bcm, Gm in Gms so se odlagali v recnih koritih ter v nanosih aluvialnih pahljac. Pešceni litofaciesi Sm, Sm(d) in Sp predstavljajo pešce­ne sipine, najbolj drobnozrnati sedimenti Fm in Fm(d) pa sedimente poplavnih ravnic ter drob­nozrnate nanose aluvialnih pahljac. Debelozrna-ti in slabo sortirani prodnati faciesi s slabo do dobro zaobljenimi klasti nakazujejo relativno kratek transport, kar je v skladu z rezultati ana­lize provenience klastov (glej nadaljevanje dis-kusije). Odlaganje aluvialnih sedimentov v CB in DPB se je odvijalo socasno z zniževanjem erozijske baze in relativnim dvigovanjem površja, kar se odraža v inverzni stratigrafiji teras (sl. 9). Povr­šina poplavne ravnice (PR) v CB in DPB ima jas-no razvidno morfologijo in zelo dobro ohranjene opušcene recne meandre, ki nakazujejo na pre­pletajoc recni sistem Savinje in Drave pred re-gulacijo strug. Ocenjena starost poplavne ravni­ce je holocen. Višje ležecim terasnim nivojem in vršajem so pripisane interpretativne starosti na podlagi tradicionalne morfostratigrafije (Buser, 1979; Mioc & Žnidarcic, 1989), primerjave z dru­gimi bazeni v regiji (npr.: Krški bazen: Verbic, 2004; Velenjski bazen: Drobne, 1967; Rakovec, 1968; Ljubljanski bazen: Pavich & Vidic, 1993) ter na podlagi novih opazovanj, ki so predmet te študije. Spodnji terasni nivo obsega terasi T0 in T1 v CB ter terase T0, T1 in T2 v DPB, ki se nahajajo E.MENCIN GALE, P. JAMŠEK RUPNIK, M. TRAJANOVA, L. GALE, M. BAVEC, F. S. ANSELMETTI & A. ŠMUC Fig. 9. Schematic profile of the terrace and fan systems in the (A) Celje Basin and (B) Drava-Ptuj Basin with levels (T0, T1, T2, T3, T4 in T5) marked, together with their relative heights above the Holocene floodplain (PR). Sl. 9. Shematska profila sistema teras in vršajev v (A) Celjskem in (B) Dravsko-Ptujskem bazenu z oznacenimi nivoji (T0, T1, T2, T3, T4 in T5) ter njihovimi relativnimi višinami nad holocensko poplavno ravnico (PR). Sl. 10. Interpretacija izvornih obmocij plio-zgodnjepleistocenskih prodnatih sedimentov v Celjskem (1) in Dravsko-Ptujskem bazenu (2). E.MENCIN GALE, P. JAMŠEK RUPNIK, M. TRAJANOVA, L. GALE, M. BAVEC, F. S. ANSELMETTI & A. ŠMUC CB and up to 14 m above the floodplain in DPB. Terrace treads and risers are very well preserved, terrace treads are typically wide and (almost) flat surfaces. Lidar data show that the terrace treads have preserved abandoned river meanders, which are common and moderate to well preserved in DPB, whereas rare and poorly preserved in CB. Terrace treads gently slope in direction consist­ ent with the flow of present streams. Sediments of these terraces are composed of carbonate gravel exhibiting only low degree of weathering. Ter­race riser’s heights (e.g. between T0 and T1; be­tween T1 and T2) are relatively low (2-5 m). Since the terraces T0, T1 and T2 have well preserved geomorphic traces of former river system, which is typical for youngest Quaternary periods (e.g. Blum & Törnqvist, 2000; Lewin & Macklin, 2003), and are older than the Holocene floodplain, we interpret the age of the low-level terrace group of Late Pleistocene. Middle-level terrace group comprises terraces and fans T3 occurring at up to 14 m above the floodplain in CB and up to 23 m above the flood­plain in the DPB. Similarly, as in low-level ter­race group, their gravel is composed of carbonate clasts and exhibits low degree of weathering. Their terrace treads slope in direction consistent with the flow of present streams. In contrast with the low-level terrace group, the degree of terrace preservation is lower, and terrace treads occur in considerably less extensive surfaces in mid-dle-level terrace group. Therefore, we interpret the terraces and fans T3 are of Middle Pleisto­cene age. High-level terrace group encompasses terrac­es and fans T4 and T5. Compared to middle-lev­el terrace group, T4 and T5 have several levels occurring at different relative height from ap­proximately 40 to 124 m above the floodplains. Terrace, and fan surfaces are strongly degraded. Surfaces are not flat anymore but have developed a rough relief because of degradation processes. Often the surfaces are only remnants of former morphology of sedimentary bodies, preserved in narrow, flat-crest tops. Risers are clearly visible as scarps between two terrace levels but are of­ten strongly eroded by ephemeral and perenni­al streams. Risers are considerably higher than risers in low- and middle-level terrace group. The degree of weathering of sediments (clasts) in CB is significantly higher than in low- and mid-dle-level terrace group, the prominent differ­ence is also in lithologic composition of gravel, which is here exclusively non-carbonate. In DPB, sediments of this group are as well much more do približno 8 m nad poplavno ravnico v CB in do 14 m nad poplavno ravnico v DPB. Terase in ježe teras so zelo dobro ohranjene, pri cemer terasne ravnine zavzemajo znacilno široke in ravne povr­šine. Lidarski posnetki kažejo na površinah teras opušcene recne meandre, ki so ponekod pogostej­ši in srednje dobro do dobro ohranjeni (DPB), po­nekod pa redki in slabše ohranjeni (CB). Terasne površine vpadajo v smeri današnjih vodotokov. V sestavi sedimentov nastopa zgolj malo preperel karbonatni prod. Višina ježe teras med sosednje ležecimi terasami (npr. med T0 in T1; med T1 in T2) je relativno majhna (od 2 do 5 m). Glede na to, da imajo terase T0, T1 in T2 dobro ohranjene geomorfne sledove nekdanjega recnega sistema, kar je znacilno za najmlajša obdobja kvartarja (npr. Blum & Törnqvist, 2000; Lewin & Macklin, 2003), in da so starejše od holocenske PR, je in-terpretirana starost spodnjega terasnega nivoja pozni pleistocen. Srednji terasni nivo obsega terase in vršaje T3, ki se nahajajo do 14 m nad poplavno ravnico v CB in do 23 metrov nad poplavno ravnico v DPB. Ceprav je prod, tako kot v spodnjem te­rasnem nivoju, nepreperel in karbonatne sesta­ve, površine pa prav tako vpadajo v smeri da­našnjih vodotokov, so slednje za stopnjo slabše ohranjene in obsegajo znatno manjše površine kot terase spodnjega terasnega nivoja. Zato so terase in vršaji T3 interpretirani kot srednjeple­istocenski. Zgornji terasni nivo obsega terase in vršaje T4 in T5. Za razliko od srednjega terasnega nivoja je v T4 in T5 grupiranih vec nivojev površin, ki se pojavljajo na razlicnih relativnih višinah od približno 40 do 124 m nad poplavnimi ravnicami. Površina teras in vršajev je mocno degradirana. Ni vec ravna, temvec je hrapava zaradi delovanja degradacijskih procesov in pogosto omejena le na ostanke nekdanjih površinskih oblik, ohranjenih v ozkih grebenih. Ježe teras so jasno razvidne kot stopnje med dvema nivojema teras, vendar so po­gosto mocno precno erodirane z obcasnimi ali stalnimi potoki, višine jež pa so znatno višje kot v nižjem in srednjem terasnem nivoju. Stopnja pre­perelosti sedimentov (prodnikov) v CB je znatno višja kot v spodnjem in srednjem terasnem nivo­ju, izrazita pa je tudi razlika v litološki sestavi proda, ki je tu izkljucno nekarbonaten. V DPB so sedimenti prav tako znatno bolj prepereli, a raz-like v litološki sestavi z nižjima sistemoma teras ni, kar je bilo ugotovljeno že v preteklih raziska­vah (Mioc & Žnidarcic, 1989). Terase in vršaji zgornjega terasnega nivoja so bile tako v skladu s podatki Osnovne geološke karte (Buser, 1979; weathered, but there is no difference in lithologic composition compared to lower terrace groups, as already pointed out by previous investigations (Mioc & Žnidarcic, 1989). Terraces and fans of high-level terrace group were thus interpreted as Plio-Early Pleistocene, which agrees with Ba­sic geologic map (Buser, 1979; Mioc & Žnidarcic, 1989). It is important to note, however, that sed­iment deposition in terraces, related to strong climate changes, typical for Quaternary, as well as numerical age dating from other compara­ble intramountain basins in the region (Cline et al., 2016) and previous observations (e.g. Kušcer, 1993) indicate mostly Early Pleistocene and not Pliocene age. Provenance of the Plio-Early Pleistocene sediments The interpretation of the provenance of the Plio-Early Pleistocene sediments in the CB and the DPB is based on clast lithological analysis. We focused on the indicative lithologies; these are lithologies that can be attributed to certain formation with high reliability and that are out­cropping on a relatively small area (Büchi, 2016). Interpretation of the possible source areas of Plio-Early Pleistocene gravel deposits in the CB and DPB is depicted in the figure 10. Celje Basin The provenance of the Plio-Early Pleistocene sediments in the CB is constrained with meta­morphic, volcanic and volcaniclastic and clas-tic rocks (Table 4). In the group of metamorphic rocks filitoid mica schist is the main indicative lithology, which was sampled from the sediments on the southern margin of the CB. The occur­rence of this type of metamorphic rocks is lim­ited to the area of the Eastern Alps, outcropping only north of the CB (in the area of the Hudinja spring). However, the dip of the sampled terraces is indicating the sediment supply from the south. Regarding these two contradictory arguments, we propose that ether i) these metamorphic clasts are resedimented from older (possibly Miocene; Ivancic et al., 2017) deposits from the south of the CB, which were originally deposited from the north or that ii) the present day dip of the terrace surfaces is a result of post-sedimentary tectonics and does not correspond to the direction of the drainage system in the Plio-Early Pleistocene. In the group of the volcanic and volcaniclastic rocks Triassic and Oligocene clasts were identi­fied. The outcrops of Triassic volcanic rocks are located on the northern, western and southern Mioc & Žnidarcic, 1989) uvršcene v plio-zgodnji pleistocen. Pri tem je potrebno poudariti, da na- cin odlaganja sedimentov v terasah, ki je pogojen z mocnejšimi podnebnimi nihanji, znacilnimi za obdobje kvartarja, podatki numericnih datacij v drugih primerljivih medgorskih bazenih v regi­ji (Cline et al., 2016) ter predhodna opazovanja (npr. Kušcer, 1993) nakazujejo v vecji meri zgo­dnjepleistocensko in ne pliocensko starost. Provenienca plio-zgodnjepleistocenskih sedimentov Provenienca plio-zgodnjepleistocenskih se­dimentov je interpretirana na osnovi litološke analize klastov. Med vsemi dolocenimi litotipi so za interpretacijo provenience prodnatih sedi­mentov CB in DPB pomembne tako imenovane indikativne litologije, t.j. litologije, ki se lahko z veliko stopnjo zanesljivosti pripišejo doloceni formaciji in izdanjajo na relativno majhnem ob-mocju (Büchi, 2016). Današnja prostorska razšir­jenost formacij, ki bi lahko bile izvor indikativ­nih litologij, prepoznanih v plio-pleistocenskih prodnih sedimentih CB in DPB, je prikazana na sliki 10. Celjski bazen Provenienco plio-zgodnjepleistocenskih sedi­mentov v CB nakazujejo skupine metamorfnih, vulkanskih in vulkanoklasticnih ter klasticnih kamnin (Tabela 4). V prvi skupini je indikativna litologija filito­idni sljudnati skrilavec, najden v sedimentih na južnem robu CB. Danes izdanja v bližini izvira potoka Hudinja, severno od CB, ne pa tudi na južnih obronkih CB. Nagib vzorcenih teras sicer nakazuje pritok iz juga CB, vendar pa se izvor­ne metamorfne kamnine, omejene na obmocje Vzhodnih Alp, pojavljajo le severno od CB. Glede na nasprotujoca si argumenta se porajajo dodatne interpretacije, in sicer i) da so prodniki omenje­ne litologije resedimentirani iz nanosov starejših paleopritokov, ki so prihajali s severa (miocenski sedimenti?; Ivancic et al., 2017) ali pa ii), da je da­našnji nagib teras rezultat post-sedimentacijske tektonike in ne ustreza smeri drenaže v plio-zgo­dnjempleistocenu. V skupini vulkanskih in vulkanoklasticnih kamnin so bili ugotovljeni prodniki triasnega in oligocenskega vulkanizma. Prvi se pojavlja v manjših erozijskih ostankih na severnih, zaho­dnih in južnih pobocjih CB, drugi pa na širšem obmocju severno in zahodno od CB, kar ustreza provenienci paleo-Savinje (Buser, 2010). E.MENCIN GALE, P. JAMŠEK RUPNIK, M. TRAJANOVA, L. GALE, M. BAVEC, F. S. ANSELMETTI & A. ŠMUC hillslopes of the CB and occur as smaller erosional remnants (Buser, 2010). The outcrops of the Oligo­cene volcanic rocks can be found in a wider area north and west of the CB. This corresponds to the provenance of paleo-Savinja and its tributaries. The outcrops of clastic Carboniferous rocks are located on the southern, northern and north­western hillslopes of the CB (Buser, 2010) which corresponds to the provenance of the paleo-Paka, paleo-Savinja and their tributaries. Source areas of Plio-Early Pleistocene sedi­ments are therefore located in the vicinity of the deposits. Hence, we interpreted that the drainage system of the paleo-Savinja and its tributaries in Pliocene-Quaternary corresponds to the present one. Drava-Ptuj Basin In the DPB two indicative lithogroups were identified; metamorphic rocks are prevailing in the NV and HO samples and carbonate rocks present solely in RA and SKA samples (Table 5). Varieties of amphibolite and epidote am-phibole schists originate from Pohorje Massif and Kozjak mountain range (Buser, 2010). Mica schists and schists corresponds to the lithologies that are typical for the wider area of the Eastern Alps. The clasts likely originate from the Pohor­je Massif and Kozjak mountain range, however the provenance from the area between Ravne na Koroškem and Dravograd and further away from Eastern Alps in Austria cannot be excluded. Slate varieties were interpreted to originate from Magdalensberg series located on the western part of the Pohorje Massif and in Kozjak mountain range (Buser, 2010). The group of metamorphic rocks in the NV and HO samples was therefore attributed to the provenance of paleo-Drava and its tributaries. Carbonate rocks were identified solely in the RA and SKA samples which corresponds to the provenance of paleo-Dravinja and its tributar­ies. Permian carbonate rocks were attributed to Lower Permian Dovžanova soteska and Trog­hofel Formations that can be found in the area around Slovenske Konjice (Buser, 2010). Vari­eties of Triassic carbonate rocks are located in the area west and north of the Slovenjske Konjice and Zrece. Upper Cretaceous carbonate rocks were attributed to rudist limestone from Gossau group (Plenicar, 1993; Moro et al., 2016) and occu­py area east and west of Zrece (Buser, 2010). Igneous rocks were, despite the immediate vicinity of the Pohorje Massif, not found in any of studied localities. Based on structural, radi­ Klasticne kamnine karbonske starosti se da­nes v primarni legi pojavljajo na južnih, severnih in severozahodnih obronkih CB (Buser, 2010), kar ustreza provenienci paleo-Pake, paleo-Savinje ter njunih pritokov. Izvorna obmocja plio-zgo­dnjepleistocenskih sedimentov se torej nahajajo v relativni bližini obravnavanih recnih nanosov, recna mreža v pliocenu-kvartarju pa je potekala v skladu z današnjo drenažo, torej s smerjo toka Savinje in manjših potokov z obronkov CB. Dravsko-Ptujski bazen V DPB sta bili ugotovljeni dve indikativni skupini kamnin, in sicer metamorfne kamnine, ki mocno prevladujejo v vzorcih NV in HO in karbonatne kamnine, ki se pojavljajo izkljucno v vzorcih RA in SKA (Tabela 5). Razlicki amfibolita in epidotno amfibolske­ga skrilavca so bili pripisani obmocju Pohorja in Kozjaka (Buser, 2010). Znacilnosti skupine blestnikov in skrilavcev ustrezajo razlickom, ki se pojavljajo na širšem obmocju Vzhodnih Alp. Predvidevamo donos s Pohorja in Kozjaka, manj verjetno pa iz bolj oddaljenega obmocja med Rav­nami na Koroškem in Dravogradom in seveda naprej iz avstrijskega dela Vzhodnih Alp. Skupi-no glinastih skrilavcev (ang. slate) smo povezali s Štalenskogorsko serijo, ki se nahaja na zahod­nem Pohorju in na Kozjaku (Buser, 2010) ter jo danes erodirajo pritoki Drave. Skupini metamor­fnih kamnin v vzorcih NV in HO je bila tako pri­pisana drenaža paleo-Drave in njenih pritokov. Karbonatne kamnine so bile ugotovljene le v vzorcih RA in SKA, kar generalno ustreza dre­naži paleo-Dravinje in njenih pritokov. Permske karbonatne kamnine so bile pripisane spodnje­permski Dovžanosoteški in Trogkofelski for-maciji, ki izdanjata v okolici Slovenskih Konjic (Buser, 2010). Pojavnost razlickov triasnih kar­bonatnih kamnin je omejena na obmocje zahodno in severno od Slovenskih Konjic in Zrec. Zgor­njekredne kamnine so opredeljene kot rudistni apnenci Gossauske grupe (Plenicar, 1993; Moro et al., 2016), ki izdanjajo vzhodno in zahodno od Zrec (Buser, 2010). Kljub pricakovanjem, magmatskih kamnin s Pohorja na vzorcenih lokacijah nismo našli. Gle­de na dosedanje strukturne, radiometricne in pa-leomagnetne raziskave (Márton et al. 2006; Tra­janova et al. 2008; Fodor et al. 2008; Trajanova, 2013) se osnovna morfologija Pohorja, kljub levi (ccw) rotaciji bloka, v casu kvartarja ni bistveno spremenila. Zato sklepamo, da je bil tudi drenaž­ni sistem podoben današnjemu. Kot je razvidno s slik 1 in 3, nobeden od današnjih vodotokov, ometric and paleomagnetic analyses (Márton et al., 2006; Trajanova et al., 2008; Fodor et al., 2008; Trajanova, 2013) the morphology of the Pohor­je Massif in the Quaternary, despite its counter­ clockwise rotation, did not changed significantly. Therefore, the drainage system was presumably similar as today. None of the present-day streams reach up to the granodioritic pluton. (Figs. 1, 3). Besides, the relief of its eastern part in the late Miocene is modeled to be significantly higher and gravitationally disintegrated in the latest Mio­cene-Pliocene (Trajanova, 2013), which would yield that erosion and transport of the granodi­ orite to the DPB in the Quaternary was even less likely. The results of the provenance analysis indicate two different source areas of the Plio-Early Pleis­tocene sediments; paleo-Drava and paleo-Drav­inja. Moreover, the river system in the Plio-Early Pleistocene is similar to the present one, which corresponds to the previous studies in the area of the Eastern Alps (e.g. Keil and Neubauer, 2009). Enigmatic carbonate clasts in the “Plio-Quaternary” sediments? In the wider Alpine foreland area, there are several examples from Switzerland (Graf, 1993; Preusser et al., 2011), Germany (Doppler et al., 2011; Ellwanger et al., 2011) and Austria (van Husen & Reitner, 2011), where the criteria for distinguishing different terraces is the presence/ absence of carbonate clasts. A similar model is currently applied in the Krško Basin, where Plio-Early Pleistocene gravel (Globoko Allofor­mation, Verbic, 2008) is characterized as non-car­bonate gravel (e.g. Poljak, 2017). However, several authors (Verbic, 2008; Mencin Gale, unpublished data) report an exception in the Libna locality. The absence of carbonate clasts was in the previ­ous studies explained with i) in-situ dissolution of the carbonates (Kušcer, 1993) or with ii) disso­lution of the carbonate gravel during the trans­port and resedimentation (Verbic, 2008). Both ex­planations are therefore climate-related. On the contrary, carbonate clasts were reported in sev­eral “Plio-Quaternary” basins in the region; the Velenje Basin (Mioc, 1978; Kralj et al., 2018) and DPB (Mioc & Žnidarcic, 1989; this study). There­fore, we propose an alternative explanation that the presence of the carbonate clasts in these ba­sins is not climate-related but rather dependent from the vicinity of the carbonate source rocks and the evolution of the drainage network. ki precijo obravnavano obmocje, ne sega do gra­nodioritnega plutona. Glede na model nastanka Pohorskega tektonskega bloka (Trajanova, 2013) je bil relief njegovega vzhodnega dela v casu po­znega miocena celo znatno višji in je gravitacij­sko razpadal koncem miocena in v pliocenu. Za­radi tega je erozija in transport granodiorita na obravnavano obmocje še manj verjetna. Rezultati analize provenience nakazujejo dve glavni izvorni obmocji plio-zgodnjepleisto­censkih sedimentov DPB, in sicer provenienci paleo-Drave in paleo-Dravinje. Nadalje, recna mreža je v plio-zgodnjempleistocenu potekala v skladu z današnjo, kar je v skladu z drugimi opa­zovanji na širšem obmocju Vzhodnih Alp (npr. Keil and Neubauer, 2009). Enigmaticni karbonatni prodniki v »pliokvartarnih » sedimentih? V širšem prostoru alpskega predgorja, kot na primer v Švici (Graf, 1993; Preusser et al., 2011), Nemciji (Doppler et al., 2011; Ellwanger et al., 2011) in v Avstriji (van Husen & Reitner, 2011), terase pogosto locujejo na podlagi vsebnosti karbonatnih prodnikov. Podoben kriterij za lo­cevanje razlicnih prodnatih zasipov je trenutno uveljavljen tudi v Krškem bazenu. Eden od kri­terijev za locevanje Plio-zgodnjepleistocenskih sedimentov Krškega bazena (Globoška alofor­macija; Verbic, 2004) od mlajših sedimentov je prisotnost izkljucno nekarbonatnega proda (npr. Poljak, 2017), ceprav Verbic (2008) navaja izje-mo prisotnosti karbonatnega proda na obmocju Libne (potrjeno tudi z osebnimi podatki Men-cin Gale). Odsotnost karbonatnih prodnikov v plio-zgodnjepleistocenskih sedimentih Krškega bazena je možno pojasniti na dva nacina: i) in­-situ raztapljanje že odloženega karbonatnega proda (Kušcer, 1993), ali ii) raztapljanje karbo­natnega proda med veckratno resedimentacijo recnih nanosov (Verbic, 2008). Obe razlagi torej širše gledano pogojujeta podnebno-odvisen pro-ces. Nasprotno so bili »pliokvartarni« karbonat­ni prodniki dokumentirani v nekaterih drugih medgorskih bazenih v regiji, na primer v Velenj­skem bazenu (Mioc, 1978; Kralj et al., 2018) in v DPB (Mioc & Žnidarcic, 1989; pricujoca študija). Ob navedenih dejstvih se tako pojavi dodatna interpretacija, da v omenjenih bazenih ne gre pogojevati vsebnosti karbonatnih prodnikov s podnebnimi procesi, temvec z bližino izvornega obmocja karbonatnih kamnin in razvojem recne mreže. E.MENCIN GALE, P. JAMŠEK RUPNIK, M. TRAJANOVA, L. GALE, M. BAVEC, F. S. ANSELMETTI & A. ŠMUC Conclusions Investigation of Plio-Early Pleistocene sedi­ments in the Celje and Drava-Ptuj basins bring new insights on the genesis, composition, mor­phostratigraphy and provenance of these sed­iments. Due to higher resolution obtained with detailed morphostratigraphy in this paper, we propose that the former chronostratigraphic name of the studied unit “Plio-Quaternary” is replaced with “Plio-Early Pleistocene”. Plio-Ear­ly Pleistocene, Middle Pleistocene and Late Pleis­tocene sediments were deposited in alluvial en­vironments and are preserved in several terrace and fan levels. Interpreted terrace and fan ages are based on several morphological and sedimen­tological criteria. The low-level terrace group encompasses terraces T0, T1 and T2 with an in­terpreted Late Pleistocene age. The middle-level terrace group represented by terraces and fans T3 is attributed to the Middle Pleistocene. The high-level terrace group comprised of terraces and fans T4 and T5 is interpreted to the Plio-Ear­ly Pleistocene. The provenance of Plio-Early Pleistocene sediments is attributed to local source areas, which is supported by facies analysis of sedi­ments, suggesting short transport, and prove­nance analysis of clasts. Metamorphic clasts in Plio-Early Pleistocene sediments of the Celje Basin originate from the southern Pohorje Mas­sif, while clasts of volcanic, volcaniclastic and clastic rocks originate from northern, western and southern hillslopes of the Celje Basin. This is consistent with drainage of the paleo-Savinja and its tributaries. Clasts of metamorphic rocks in Plio-Early Pleistocene deposits of the Dra­va-Ptuj Basin probably originate mostly from Pohorje Massif and Kozjak area, and carbonate clasts are presumably from surroundings of Slovenske Konjice and Zrece. The provenance of clasts from Drava-Ptuj Basin is therefore related to the drainages of paleo-Drava, paleo-Dravinja and their tributaries. Our results thus indicate that the drainage in Plio-Early Pleistocene cor­responded to present one, in agreement with oth­er observations from the Eastern Alps. Acknowledgements This work was supported by the Slovenian Research Agency (ARRS) in the frame of the Young Researchers (38184), the Regional Geology (P1-0011) and Mineral Resources (P1-0025) research pro-grammes and was carried out at the Geological Survey of Slovenia and University of Bern, Switzerland. Zakljucki Raziskave plio-zgodnjepleistocenskih sedi­mentov v Celjskem in Dravsko-Ptujskem ba­zenu so pokazale nova spoznanja na podrocju geneze, sestave, morfostratigrafije in provenien­ce sedimentov. Zaradi višje locljivosti, ki teme­lji na detajlni morfostratigrafiji v tem clanku opušcamo do sedaj ustaljeno kronostratigraf­sko ime enote »pliokvartar« ter predlagamo ime plio-zgodnjepleistocenski sedimenti. Plio-zgo­dnjepleistocenski, srednjepleistocenski in pozno­pleistocenski sedimenti so se odlagali v recnem okolju ter so ohranjeni v vec terasnih in vršajnih nivojih. Interpretirane starosti teras in vršajev temeljijo na vec morfoloških in sedimentoloških kriterijih. Spodnji terasni nivo obsega terase T0, T1 in T2 z interpretirano poznopleistocensko starostjo. Srednji terasni nivo obsega terase in vršaje T3, ki jim je bila pripisana srednjepleisto­censka starost. Zgornji terasni nivo obsega tera­se in vršaje T4 in T5 z interpretirano plio-zgo­dnjepleistocensko starostjo. Provenienca plio-zgodnjepleistocenskih sedi­mentov je bila pripisana lokalnim izvornim obmo-cjem, kar potrjuje facielna analiza sedimentov, ki kaže na krajši transport, kot tudi analiza proveni­ence klastov. Metamorfni klasti v plio-zgodnjeple­istocenskih sedimentih v Celjskem bazenu izvira­jo iz obmocja južnega Pohorja, klasti vulkanskih, vulkanoklasticnih in klasticnih kamnin pa s se­vernih, in zahodnih in južnih obronkov Celjskega bazena. Pri tem je potrebno upoštevati možnost, da so lahko nekateri klasti resedimentirani in ne odražajo smeri transporta v plio-zgodnjemplei­stocenu. Generalno pojavnost izvornih kamnin ustreza drenaži paleo-Savinje in njenih pritokov. Prodniki metamorfnih kamnin v plio-zgodnjeple­istocenskih nanosih Dravsko-Ptujskega bazena verjetno izvirajo predvsem z obmocja Pohorja in Kozjaka, karbonatni prodniki pa domnevno izvi­rajo iz okolice Slovenskih Konjic in Zrec. Izvorno obmocje klastov iz Dravsko-Ptujskega bazena je torej pogojeno z drenažo paleo-Drave in paleo--Dravinje ter njunih pritokov. Rezultati tako iz Celjskega kot iz Dravsko-Ptujskega bazena potr­jujejo, da je bila drenaža v plio-zgodnjempleisto­cenu podobna kot danes, kar je v skladu z drugimi opazovanji na širšem obmocju Vzhodnih Alp. Zahvala Raziskava je bila izvedena v okviru projekta Mladi raziskovalec (38184) in programske skupine Regionalna Geologija (P1-0011) ter Mineralne surovi­ne (P1-0025), ki jih financira Javna agencija za razi­skovalno dejavnost Republike Slovenije (ARRS). Delo Eva Mencin Gale was additionally supported by the Swiss Government Excellence Scholarship for Foreign Scholars and Artists. The authors would like to express gratitude to Polona Kralj for petrographic analysis of the volcanic and volcaniclastic rocks and for contribution in the discussion, Dragomir Skaberne for conducting petrographic analysis of the clastic rocks, Matevž Novak for determination of the Permian fossils and Mladen Štumergar for the preparation of the samples and thin-sections. We would also like to express our thanks to two anonymous reviewers for the constructive review that significantly improved this paper. je bilo izvedeno na Geološkem zavodu Slovenije in na Univerzi v Bernu v Švici. Dodatno je bila raziskava fi­nancirana s štipendijo »Swiss Government Excellence Scholarship for Foreign Scholars and Artists« s strani švicarske vlade. Avtorji se zahvaljujejo Poloni Kralj za izvedene petrografske analize vulkanskih in vu­ lkanoklasticnih kamnin ter za doprinos k diskusiji, Dragomirju Skabernetu za izvedbo petrografskih ana­ liz klasticnih kamnin, Matevžu Novaku za dolocanje permskih fosilov ter Mladenu Štumergarju za pripra­vo vzorcev in zbruskov. Prav tako pa se zahvaljujemo dvema anonimnima recenzentoma za njune konstruk­ tivne pripombe, ki so pripomogle k izboljšanju clanka. Literatura Altherr, R., Lugovic, B., Meyer, H. 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CC Atribution 4.0 License https://doi.org/10.5474/geologija.2019.010 Multielemental composition of some Slovenian coals determined with k0-INAA method and comparison with ICP-MS method Multielementna sestava nekaterih slovenskih premogov dolocena s k0-INAA metodo in primerjava z ICP-MS metodo Tjaša KANDUC1*, Timotej VERBOVŠEK2, Rok NOVAK1 & Radojko JACIMOVIC1 1Department of Environmental Sciences, Jožef Stefan Institute, Jamova cesta 39, SI-1000 Ljubljana, Slovenia; e-mail: tjasa.kanduc@ijs.si 2Department of Geology, Faculty of Natural Science and Engineering, University of Ljubljana, Aškerceva 12, 1000 Ljubljana, Slovenia Prejeto / Received 4. 10. 2019; Sprejeto / Accepted 4. 12. 2019; Objavljeno na spletu / Published online 24. 12. 2019 Key words: k0-instrumental neutron activation analysis (k0-INAA), multielemental composition, coal, PCA analysis, Slovenia Kljucne besede: k0-instrumentalna nevtronska aktivacijska anliza (k0-INAA), multielementna sestava, premog, PCA analiza, Slovenija Abstract In this multi-elemental study, 34 elements (Ag, As, Au, Ba, Br, Ca, Cd, Ce, Co, Cr, Cs, Eu, Fe, Ga, Hg, Hf, K, La, Mo, Na, Nd, Rb, Sb, Sc, Se, Sm, Sr, Ta, Tb, Th, U, Yb, Zn and Zr) were analysed in Slovenian coals from operative (Velenje) and non-operative (Kanižarica and Senovo) coal mines and an imported Indonesia coal using k0-Instrumental Neutron Activation Analysis (k0-INAA) and compared to inductively coupled plasma-mass spectroscopy (ICP-MS). Weaker regressions between both methods ICP-MS and k0-INAA are obtained for following elements: Cs, Co, Eu, Se, Sm and Tb with low concentration (below 1 mg/kg). The k0-INAA data are comparable to the ICP-MS data for the majority of elements. The levels of major elements measured with k0-INAA are as follows: Ca>Fe>K>Na>Sr>Ba. Minor and trace elements, as well as rare earth elements (REEs), are comparable with coal values worldwide. Data of trace elements in coal are important since they are related to air emissions. According to our data obtained with both methods (ICP-MS and k0-INAA) we can conclude that concentrations of trace elements, which impact to human health and are combusted (Indonesian and Velenje coal) in Slovenia are comparable to world averages coal. Izvlecek V tej raziskavi smo izmerili s k0-INAA (instrumentalno nevtronsko aktivacijsko analizo) metodo nekaj izbranih slovenskih premogov iz velenjskega premogovnika in ne operativnih premogovnikov: Kanižarica in Senovo. Prav tako smo s to metodo analizirali vzorec iz Indonezije (uvožen premog) in ga primerjali z že objavljenimi rezultati pridobljenimi z ICP – MS (masna spektrometrija z induktivno sklopljeno plazmo) metodo. S k0-INAA metodo smo dolocili naslednje elemente: Ag, As, Au, Ba, Br, Ca, Cd, Ce, Co, Cr, Cs, Eu, Fe, Ga, Hg, Hf, K, La, Mo, Na, Nd, Rb, Sb , Sc, Se, Sm, Sr, Ta, Tb, Th, U, Yb, Zn in Zr. Rezultati meritev pridobljeni s k0-INAA metodo so za vecino elementov, obravnavanih v tej raziskavi, primerljivi z rezultati meritev pridobljenih z ICP-MS metodo. Slabše regresije med metodami ICP-MS in k0-INAA dobimo le pri nekaterih elementih (Cs, Co, Eu, Se, Sm and Tb) za katere so znacilne nizke koncentracije (pod 1 mg/kg). Koncentracije glavnih elementov merjenih s k0-INAA metodo v premogu se znižujejo kot sledi: Ca> Fe> K> Na> Sr> Ba. Elementi z nizkimi koncentracijami in elementi redkih zemelj (REE) so primerljivi z vrednostmi premoga po vsem svetu. Podatki slednih elementov v premogu so pomembni, ker so povezani z emisijami v zraku. Glede na naše podatke pridobljene z obema metodama (ICP­MS, k0-INAA) lahko zakljucimo, da so koncentracije slednih elementov, ki vplivajo na clovekovo zdravje in jih sežigamo (premog iz Velenja in Indonezije) v Sloveniji primerljivi s povprecnimi vrednostmi svetovnih premogov. Introduction The chemical analysis of coal includes, as well as, proximate (Khandelwal and Singh, 2010, Yi et al., 2017) (moisture, volatile compounds, ash content, fixed carbon) and ultimate analyses (car­bon, hydrogen, sulphur, oxygen, and nitrogen), the analysis of major, minor and trace elements. Usually, these elements are measured using in­ductively coupled plasma-mass spectrometry (ICP-MS) (Finkelman et al., 2018) and instrumen­tal neutron activation analysis (k0-INAA) (Wag­ner and Matiane, 2018, Lin et al., 2018) methods. Other methods for determining trace elements in­clude inductively coupled plasma optical emission spectrometry (ICP-OES) (Finkelman et al., 2018), hydride generation atomic absorption spectrome­try (HAAS) (Chen et al., 2011) and X-Ray Fluores­cence spectrometry (XRF) (Chen et al., 2011). It is widely known that these trace elements can occur in a wide variety of chemical forms or modes of occurrence, which determines the environmental, economic, technological impact, which in some cases can be significant (Finkelman, 1995, 2018). Twenty-five potential harmful trace elements (PHTEs) are typically present in coal in inorgan­ic and organic forms (Radenovic, 2006). Among them As, Be, Cd, Cr, Co, Hg, Mn, Ni, Pb, Se, Sb and U are all potential air pollutants (Grdal, 2008). Ketris and Yudovich (2009) include rare earth elements, yttrium, and scandium (REY + Sc) in the table of coal Clarke values, which has been a highly useful tool for making geochemical comparisons of coals globally. Indonesian coals are generally low in ash and sulphur, but have high content of volatile matter. They are classified as low rank coals with low caloric value. The sulphur content varies from 0.1 to 1 % (Internet 1). Elemental composition (wt %, dry basis) of TOT S varied for Velenje samples from this study from 1.4 to 3.9 %, Kanižari-ca from 1.6 to 2.2 % and Senovo 1.9 % (Burnik Šturm et al., 2009). The geological composition of the Velenje ba­ sin is described in detail in Brezigar et al. (1987). The origin of the Velenje basin is related to the transtention between Šoštanj and Smrekovec faults. In the pre-Pliocene basement of the ba­sin, Triassic carbonates and dolomites prevail on the northeastern side of the Velenje fault, while Oligocene to Miocene clastic strata, consisting predominantly of marls, sandstones and volca­noclastics are dominant on the south-western side of the fault. The alkaline, calcium-rich envi­ronment during formation of Velenje basin also caused a relatively high degree of gelification, which is significantly higher than the degree of gelification observed in other lignites (Markic & Sachsehofer, 1997; Šlejkovec & Kanduc, 2005; Markic & Sachsehofer, 2010) as well as coals in­vestigated in our study. A well known relation between alkalinity and gelification was clearly ascertained in the case of the Velenje lignite. Lignite samples with the highest calcium con­tents were also the samples with the strongest gelification (Markic & Sachsenhofer, 1997). The macroscopic description of the lignite samples, in term of lithotypes, was determined following the lithotype classification criteria for brown coals (lignites) provided by the International Committee for Coal Petrology (ICCP, 1993) and are described by Burnik Šturm et al. (2009). All of the samples from the Velenje excavation field -50/C in this study are classified as gelified de­trital lignite (Kanduc et al., 2018). The lithologi-cal columns for Senovo, Kanižarica and Trbovlje are also presented in Burnik Šturm et al. (2009) and references therein (Brezigar, 1987; Kušcer, 1967; Markic et al., 1991). The macroscopic de­scription of the lignite samples in terms of previ­ ous petrological (Markic & Sachsenhofer, 1997), geochemical and isotopic studies of light ele­ ments C, H, O, N, S (Bechtel et al., 2003; Kanduc et al, 2005; Burnik Šturm et al., 2009; Kanduc & Šlejkovec, 2005; Kanduc et al., 2012; Kanduc et al., 2018; 2019, Liu et al., 2019) were performed in the frame of various research projects. For example, three different lithotypes (xylitic, geli­fied and matrix) of Pliocene lignite for the Ve­lenje basin, Slovenia, were investigated to estab­lish the variations of biomarker compositions in solvent extracts and stable isotope composition of carbon and nitrogen in bulk material (Liu et al., 2019). All of these studies were focused on the Velenje basin since it is currently the only actively mined basin in Slovenia and is one of the biggest underground coal mines in Europe. All three of the Velenje lithotypes reflect the composition of the original plant material in the paleomire (Markic & Sachsenhofer, 1997). Arse­nic speciation studies and the different forms of calcite present in the coal suggest that bacterial activity was a significant factor during sedimen­tation of the basin (Kanduc & Šlejkovec, 2005; Kanduc et al., 2018; Kanduc et al., 2019a). The analysis of other geological matrixes such as coalbed gas (Kanduc & Pezdic, 2005; Kanduc et al., 2012, Sedlar et al., 2014) and groundwater (Kanduc et al., 2014; Kanduc et al., 2019b) reveal more evidence of bacterial activity during sedi­mentation of the basin. In the study of Kanduc et al. (2019a) organic and inorganic coal samples from -50/C excava­ tion field of Velenje basin were measured using ICP-MS and revealed that the concentrations of the majority of the analysed elements were ei­ther equal to or below the global average for coal. Exceptions were Mo (7.76 ± 4.76 µg/g, 3.5 times higher) and U (5.24 ± 3.23 µg/g, 1.8 times higher) in organic-rich samples. It was found that higher than normal are concentrations of U (5-15 ppm – in comparison to 0.5-10 ppm concentrations in world coals), and of Mo (5-20 ppm – in comparison to 0.1-10 ppm in in world coals). Both elements are presumed to be organically bound (Markic & Sachsenhofer, 2010). This study aims to present results of major, minor and trace elements measured using k0­INAA method in coal samples collected from operative (Velenje) and non-operative (Kanižarica and Senovo) Slovenia coal mines. The study also analysed an Indonesia coal supplied by the thermal power plant Moste. Additionally, one of the objectives was to compare k0-INAA and ICP­MS methods used to analyse the same coal samples (Kanduc et al., 2019a, Supplementary material) from Velenje coal mine and perform a statistical analysis (PCA-Principal Component Analysis) of all data (Velenje, Senovo, Kanižarica, Indonesia coals) measured with k0-INAA method. Methods Sampling locations were taken from a local borehole database in the local coordinate system from the Velenje coal mine. Coordinates were then transformed to Gauss-Krger D48 Sloveni­an national coordinate system and indicated on a hill-shaded relief map generated using the ESRI ArcGIS mapping software (Fig. 1). Figure 1A was produced using data from the Shuttle Radar To­pography Mission SRTM data at 90 m spatial reso­lution. A more detailed map (Fig. 1B), was created using the digital elevation model at a 1 × 1 m spa­tial resolution, using LiDAR data form the nation­al scanning campaign of the Slovenian territory (ARSO, 2014). Figure 1C includes the position of excavation field (-50/C) and cross-section of Velen­je basin with main geological and tectonic units. Samples of coal were collected from the fol­lowing mining areas in Slovenia (Fig. 1): Senovo (3 samples), Kanižarica (4 samples), Velenje ba­sin (7 delivery roadway samples, and 18 samples from excavation field -50/C), Indonesia (1 sample) in years 2004, 2005 and 2013. The Moste thermal power plant provided the sample of Indonesian coal. For k0-INAA analysis, samples (240-290 mg) were sealed in a pure polyethylene ampoule (SPRONK system, Lexmond, The Netherlands). For the determination of long-lived radionuclides, samples and standards (Al-0.1 %Au IRMM-530R disc of 7 mm in diameter and 0.1 mm thick) were stacked together and fixed in a polyethylene am-poule in sandwich form and irradiated for 12 hours in the carousel facility (CF) of a 250 kW TRIGA Mark II reactor (Jožef Stefan Institute, JSI) at a thermal neutron flux of 1.1×E+12 cm-2 s-1. Each sample was measured three times af­ter 2, 8-13 and 25-30 days cooling time on three absolutely calibrated HPGe detectors with 40 % and 45 % relative efficiency. Measurements were carried out at a distance such that the dead time remained below 10 % with negligible random coincidences. The detectors with 40 % relative efficiency were connected to a MULTIPORT II (Canberra) computerized multichannel analy­ser (MCA) in LT mode operating with GenieTM 2000 spectroscopy software, while the detector with 45 % relative efficiency was connected to a DSPEC PLUS (Ortec) multichannel analyser in ZDT mode operating with Maestro®-32 spectros­copy software. The HyperLab (2002) program was used for peak area evaluation, whereas for the determi­nation of f (thermal to epithermal flux ratio) and a (a parameter which represents the epithermal flux deviation from the ideal 1/E distribution) the “Cd-ratio” method for multi-monitor was applied (Jacimovic et al., 2003). The values obtained for f = 28.63 and a = -0.0011 were used to calculate the element concentrations. The elemental con­centrations and effective solid angle calculations were performed using the KayWin® (Kayzero for Windows, 2011) software package. Ranges of uncertainties with coverage factor k = 1 (%) for measured elements with k0-INAA method is as follows: i) uncertainty for elements: As, Br, Ca, Ce, Cs, Fe, Na, Sc, U, and Zn ranges from 3.5 to 7.3 % and ii) uncertainty for elements: Au, Ba, Co, Cr, Eu, Ga, Hf, Hg, K, La, Mo, Nd, Rb Sb, Se, Sm, Sr, Ta, Tb, Th, Yb, ranges from 3.5 to 28 %. Measured elements with higher concen­tration have lower uncertainties, while elements with lower concentration have higher uncertain­ties. Chemical analysis of Velenje coal samples (13­2123, 13-2125, 13-2130, 13-2134, 13-2138, 13-2141, 13-2145, 13-2157, 13-2162) were performed with ICP – MS method in ACME lab Canada (http:// acmelab.com/services/). For the analysis of SiO2, AlO, FeO, CaO, MgO, NaO, KO, MnO, TiO, 2323222 Fig. 1. General map of coals located in Slovenia showing the study area of sampled coals from Slovenia mines: Velenje Coal Basin (active coal mine, n = 25), Kanižarica (closed, n = 4), Senovo (closed, n = 3), and Indonesia (coal imported in Slovenia, n = 1). Velenje sampling locations from years 2004, n = 4 (B91, B105, B107, B113) and 2013, n = 18 (2113, 2116, 2119, 2123, 2125, 2126, 2130, 2134, 2138, 2141, 2143, 2145, 2149, 2157, 2162, 2166, 2167, 2181). B. Detailed map of Velenje sampling locations from years 2004 and 2013 are presented. C. Position of excavation field -50/C from where samples were taken and cross-section of the central part of the Velenje basin (modified from Brezigar, 1987) with main geological and tectonic units. P2O5, Cr2O3, Ce, Co, Cu, and Zn samples were mixed with a LiBO2/Li2B4O7 flux. Crucibles were fused in a furnace. The cooled beads were dis­solved in ACS grade nitric acid and analyzed by ICP and or ICP-MS. Other elements (Ce, Co, Cs, Dy, Er, Eu, Gd, La, Ni, Nb, Nd, Pr, Rb, Sm, Sr, Tb, U, Th, V, Zr, Y) were measured with ICP-MS method. Total carbon (TOT C) and total sulphur (TOT S) were measured using LECO Carbon –Sulphur analyz­er. The mean limits of detection for both elements were 0.02 %. Loss on ignition (LOI) was deter­mined by igniting a sample split and then mea­suring the weight loss. For Ag, As, Au, Bi, Cd, Hg, Mo, Ni, Pb, Sb, Se, Tl, and Zn analysis, prepared samples were digested with modified Aqua Regia solution of equal parts of concentrated HCl, HNO3 and Mi-liQ H2O for 1 h in a heating block or in a hot water bath at 95°C. Samples were made up to volume witgh diluted HCl. Sample splits of 0.5 g were an­alyzed optional 15 g or 30 g digestion available for AQ200. Samples were analyzed using induc­tively coupled-mass spectrometry (ICP-MS). The following standards were used for quality assur­ance: STD-SO-18, STD-GGC-02, STD-GS311-1 and STD OREAS45EA. Statistical analysis was conducted using the R language (R Core Team, 2019), and the signifi­cance model was set at p<0.05. A Spearman’s cor­relation analysis was used to identify the rela­tionships between 27 elements (As, Ba, Br, Ca, Ce, Co, Cr, Cs, Eu, Fe, Hf, K, La, Mo, Na, Nd, Rb, Sb, Sc, Se, Sm, Sr, Tb, Th, U, Yb and Zn) with com­plete data sets. The crossed-out values indicate where p-values exceeded 0.05. Principal component analysis (PCA) was used to differentiate (same as for Spearman correla­tion analyses) between the coal from the differ­ent mines. Due to the broad range of elemental concentrations, the dataset was central log-ra­tio transformed. Studied mines were grouped as “Open” and “Closed”. The principle component plots were made using ggplot2 in R (Wickham, 2016). Results and discussion Tables 1 and 2 give the results of the k0-INAA of 34 elements (As, Ba, Br, Ca, Ce, Co, Cr, Cs, Eu, Fe, Hf, K, La, Mo, Na, Nd, Rb, Sb, Sc, Se, Sm, Sr, Tb, Th, U, Yb, Zn) for Velenje, Senovo, and Kanižarica mines and for an imported Indone­sian coal. In a previous study by Kanduc et al. (2019a), ten oxides (SiO, AlO, FeO, MgO, CaO, 22323 NaO, KO, TiO, PO, MnO, CrO), LOI (Loss on 2222523 ignition), TOT C (Total carbon), TOT S (Total sul­ phur) (Kanduc et al., 2019a), along the following toxicologically and environmentally relevant el­ ements: As, Ba, Ce, Co, Cs, Cu, Dy, Er, Eu, Gd, Hf, La, Mo, Nb, Nd, Ni, Pb, Pr, Rb, Se, Sm, Sr, Tb, Th, U, V, Y, Zn, Zr were measured in the organic-rich component of the Velenje samples. In this study, nine samples from the Velenje coal mine (13-2123, 13-2125, 13-2130, 13-2134, 13-2138, 13-2141, 13­2145, 13-2157, 13-2162), were measured using ICP-MS and k0-INAA, while all other samples in this study were measured using only k0-INAA. For studying elemental composition of coal with k0-INAA method we choose only Velenje samples (from year 2013) that were organic rich, besides Kanižarica, Senovo and Indonesia coal samples that were sampled in years 2004 and 2005. Results of ICP – MS of major elements, LOI, TOT C, TOT S in coal samples (13-2123, 13-2125, 13-2130, 13-2134, 13-2138, 13-2141, 13-2145, 13­2157, 13-2162) collected from excavation field -50/C of Velenje basin are presented in Table 3a. Results of ICP – MS of trace elements in coal samples (13-2123, 13-2125, 13-2130, 13-2134, 13­2138, 13-2141, 13-2145, 13-2157, 13-2162) collect­ed from excavation field -50/C of Velenje basin are presented in Table 3b. Data (REEs) for coals from other locations (two power plants: Jungar (China), Tutuka (SA), Matla (SA), and the Wit-bank Coalfield (SA) are included for comparison purposes (Table 4). For quality assurance and quality control (QA/QC), in the study we used the certified refer­ence material BCR-180 Gas Coal (Fig. 2). The re­sults obtained by k0-INAA are in good agreement with the certified data for As, Hg, Se and Zn. It should be mentioned that expanded uncertainty (k=2) of mass fraction of Hg obtained via Hg-203 at 279.2 keV is relatively high in comparison with certified value due to correction from the mass fraction of Se via Se-75 at 279.5 keV, which was about 70 % (Fig. 2). Among the major elements, Ca prevails. Ma­jor oxides (CaO, Na2O, K2O, TiO2) and ultimate analysis (LOI, TOT C, TOT S) of the coal samples (13-2123, 13-2125, 13-2130, 13-2134, 13-2138, 13­2141, 13-2145, 13-2157, 13-2162) range as follows (Table 3 a): CaO from 1.91-5.21 %, Na2O rang­es from 0.04 to 0.13 %, K2O ranges from 0.007­ 0.08 %, TiO2 ranges from 0.07 to 0.08 %, TOT C ranges from 50.6 to 57.1 %, TOT S ranges from 1.17 to 2.46 %, and LOI (Loss on ignition) ranges from 86.7 to 97.1 % (Kanduc et al., 2019a). Fig­ure 3 represents the major oxides (MgO+CaO, NaO+KO, SiO+AlO+FeO) present in sam­ 2222323 ples of lignite. The data were obtained from the study by Kanduc et al. (2019a) and are present­ed in Table 3a. The major oxides in the Velen­je coal samples are CaO and MgO, suggesting that lignite was formed in a Ca-alkaline rich environment (Markic and Sachsenhofer, 1997). The most prevalent oxide is CaO (from 1.91 to 5.21 %). The concentration of oxides from the Velenje samples decrease in the following order: CaO>FeO>AlO>SiO>MgO>NaO>KO>TiO. 23232222 Only two Velenje coal samples (13-2134, 13-2145) have CaO + MgO concentrations less than 70 % (Fig. 3). Figure 4 A-C shows plots of the major (Ba, Ca, Fe, K, Sr), minor (As, Br, Ce, Co, Cr, La, Mo, Nd, Rb, Sc, U, Zn) and trace element levels (Cs, Eu, Hg, Sb, Se, Sm, Ta, Tb, Th, Yb) for each of the coal mine samples (Senovo, Kanižarica, Indone­sia, Velenje). From Figure 4A it can be observed that among major elements Ca prevailed for Ve­lenje coal mine samples, while in one sample of Senovo (Senovo 3) and Kanižarica (Kanižarica 15) Fe prevails. Some samples from Velenje mine (13-2166, 13-2167, 13-2181), from excavation field -50/C have high concentrations of Ca in the range from 163700 to 307100 mg/kg (Fig. 4 A), which is in compliance with thesis of Ca-rich envi­ronment during sedimentation of Velenje basin. Among minor elements there are huge differ­ences between coal samples between mines. The highest concentration of As, Br, Ce, Cr are ob­served in Kanižarica coal samples (Kanižarica 6, Kanižarica 15). Cr and Mo prevail in Velenje coal samples, while Br and Cr prevail in Senovo coal samples (Fig. 4 B). Kanižarica coal samples have also the highest concentration of rare elements (Cs, Eu, Hf, Ta, Th, Se, Sm) (Fig. 4 C). Sm and Th are enriched in three Velenje samples (B91, B105, 13-2149) (Fig. 4 C). Among all minor and trace el­ ements Kanižarica coal samples have the highest concentrations (Figs. 4 B, C). Figure 5 presents box-plots of the k0-IN­AA data for all coal samples. From the box-plots it appears that the abundances of Ca>Fe>K>Na>Sr>Ba prevail among major ele­ments and Mo>Zn>U>Cr>As>Br in the case of mi­ Table 1. Elements (Ag, As, Au, Ba, Br, Ca, Cd, Ce, Co, Cr, Cs, Eu, Fe, Ga, Hf, Hg, K, La, Mo, Na, Nd, Rb, Sb, Sc, Se, Sm, Sr, Ta, Tb, Th, U, Yb, Zn, Zr) measured with k 0-INAA method infollowing coal samples: Senovo (Sen., n = 3), Indonesia (Indon., n = 1), Kanižarica (Kan., n = 4), Velenje (Vel., n = 7), sampled in years 2004 and 2005. Code B91Vel. B105Vel. B106Vel. B106Vel. B113Vel. B113Vel. j.v. 3123(1,8)Vel. Sen.1 Sen.2 Sen.3 Indon. Kan.6 Kan.9 Kan.19 Kan.15 Element mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg Ag 0.8) in the case of As, Ba, Cs, Mo, Nd, Sr and U, (Fig. 6 A-D) and a good positive correlation (R2 from 0.6 to 0.8) was observed for Zn and Rb (Figs 6 B-C). Though less strong, cor­relations (R2 < 0.6) were found for Co, Eu, La, Se, Sm, Tb and Th (Figs. 6 C-D), which occur in low concentrations (< 1 mg/kg). Figure 7 shows the Spearman correlations (R2>90 %) for parameters (As, Ba, Br, Ca, Ce, Co, Cr, Cs, Eu, Fe, Hf, K, La, Mo, Na, Nd, Rb, Sb, Sc, Se, Sm, Sr, Tb, Th, U, Yb, Zn) measured with k0-INAA method from four different mining lo­cations (Kanižarica, Senovo, Indonesia, Velenje). Spearman’s correlation analysis revealed strong positive correlations (R2>0.95) between the fol­lowing elements: Ce-La, Cs-Rb, Cs-Sc, Hf-Sc, Eu-Tb, Cs-Tb, Sc-Tb, Cs-Yb, Hf-Yb, Sc-Yb, and Th-Yb. Principle component analysis (Fig. 8) reveals a strong gradient along the first PCA axis (49.5 %) and has the highest positive correlation with trace elements (e.g., Ce, Co, and Cs) and highest negative correlation with main elements (e.g. Ca, Na, B). These elements have the most discrimi­nant power separating coals from open (Velenje and Indonesia) and closed (Kanižarica and Se-novo) coal mines. The second axis explains an additional 16.1 % of the variance and correlates positively with Ba, Sr and negatively with U, Sb according to PCA multi-elemental grouping (Fig. 8). Conclusion Coal samples from Slovenia (Kanižarica, Ve­lenje, and Senovo) and Indonesia were sampled and analysed by k0-INAA in 2003, 2004 and 2013, while the Velenje coal mine samples (2013) was measured using both k0-INAA and ICP-MS to compare results obtained using both methods. Based on the comparison of both methods, it can be concluded that k0-INAA method is very accu­rate compared to ICP-MS method with no possi­bility of losses of material and contamination. A good correlation between both methods was ob­tained for Ba, Sr, Mo, Zn, U, As, Rb, Nd, while a weak correlation was observed for Th, Se, Cs, Eu, Sm and Tb. The major elements determined by k0-INAA in the Velenje lignite samples (n = 25) are Ca>Fe>Na>K>Sr>Ba while for minor and trace elements Zn>Zr>Mo>U>Br>Cr. In the coal samples from the Kanižarica mine (n=4), the levels of the main elements are Fe>Ca>K>Na>Sr>Ba, while for minor and trace elements Cr>Zr>U>Zn>Rb>Mo. In samples from Senovo mine (n = 3) the main elements are Fe>Ca>K>Na>Sr>Ba, and for trace elements Cr>Zn>As>Zr>Mo, whereas in the Indonesia coal had the following composition of main elements: Fe>Ca>K>Na>Ba>Sr and trace elements: Zn>Cr>Ce>Co. In all cases, Fe and Ca are the most abundant elements, while among trace elements; Zn and Cr are the most abundant. The levels of trace elements of samples from all investigated mines were also in the same range reported in the literature for other mining 35 120 B A 30 R˛ = 0.9 100 25 R˛ = 0.9751 k0-INAA (mg/kg) R˛ = 0.9659 Ba Sr 60 k0-INAA (mg/kg) k0-INAA (mg/kg) 20 Mo R˛ = 0.72 15 Zn U 10 40 10 20 5 0 0 0 20 40 60 80 100 120 140 0 5 10152025 ICP -MS (mg/kg) ICP-MS (mg/kg) 16 1 Th C D 14 0.9 R˛ = 0.9786 R˛ = 0.8929 Co 0.8 12 Rb Se 0.7 k0-INAA method (mg/kg) R˛ = 0.8878 0.6 La As R˛ = 0.9476 R˛ = 0.8246 Cs R˛ = 0.6602 0.5 R˛ = 0.3175 R˛ = 0.594Eu 0.4 R˛ = 0.4511 Nd 0.3 0.2 4 Sm 2 R˛ = 0.5512 0.1 R˛ = 0.4364 0 Tb R˛ = 0.7729 0 0 2 4 6 8 10121416 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 ICP-MS (mg/kg) ICP -MS (mg/kg) Fig. 6. Comparison between ICP – MS and k 0 -INAA methods for 16 measured parameters in nine samples (Rb, U, La, As, Mo, Zn, Th, Co, Se, Cs, Eu, Nd, Sm, Tb, Ba, Sr) in coal. Correlation of Ba and Sr between ICP-MS and A.k -INAA. B Correlation of Mo and Zn between ICP-MS and k -INAA C. Correlation of Rb, U, La, As D. between ICP-MS and k -INAA. 00 0 Comparison of Th, Co, Se, Cs, Eu, Nd, Sm, Tb between ICP-MS and k 0-INAA. Fig. 7. Correlation matrix of measured parameters (As, Ba, Br, Ca, Ce, Co, Cr, Cs, Eu, Fe, Hf, K, La, Mo, Na, Nd, Rb, Sb, Sc, Se, Sm, Sr, Tb, Th, U, Yb, Zn) for four mining areas (Velenje, Kanižarica, Senovo, and Indonesia). The legend on the right shows statistically high correlations (up to 1). Crossed out values re­ present statistically insignificant correlations (p>0.05). Fig. 8. PCA analysis of measured pa­ rameters (As, Ba, Br, Ca, Ce, Co, Cr, Cs, Eu, Fe, Hf, K, La, Mo, Na, Nd, Rb, Sb, Sc, Se, Sm, Sr, Tb, Th, U, Yb, Zn) from different mining areas (Velenje-open, Kanižarica-closed, Senovo-closed, and Indonesia-open). regions (SA and China). Principal component analysis based on 27 elements (As, Ba, Br, Ca, Ce, Co, Cr, Cs, Eu, Fe, Hg, K, La, Mo, Na, Nd, Rb, Sb, Sc, Se, Sm, Sr, Tb, Th, U, Yb, Zn) revealed good discrimination between coal from the closed (Senovo, Kanižarica) and open mines (Velenje, Indonesia). Further geochemical investigations of coal are required to investigate composition (proximate, ultimate analysis, major, minor and environmen­tally sensitive trace elements) of coal from active excavations in the Velenje coal mine in Slovenia, which is combusted in the Šoštanj thermal power plant and represents 30 % of energetic source in Slovenia. These analyses are essential to ensure the quality of combusted coal, which is related to atmospheric emissions. Acknowledgement The authors would like to thank L1-5451, P1-0143, P1-0195 and the Young researchers pro-gramme founded by Slovenian Research Agency. 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CC Atribution 4.0 License https://doi.org/10.5474/geologija.2019.011 Risk assessment for open loop geothermal systems, in relation to groundwater chemical composition (Ljubljana pilot area, Slovenia) Ocena tveganja za odprte geotermalne sisteme, glede na kemicno sestavo podzemne vode (pilotno obmocje Ljubljana, Slovenija) Katja KOREN & Mitja JANŽA Geološki zavod Slovenije, Dimiceva ulica 14, SI-1000 Ljubljana, Slovenija; e-mail: katja.koren@geo-zs.si, mitja.janza@geo-zs.si Prejeto / Received 16. 10. 2019; Sprejeto / Accepted 5. 12. 2019; Objavljeno na spletu / Published online 24. 12. 2019 Key words: shallow geothermal energy, open loop geothermal system, groundwater, chemical composition, heat pump Kljucne besede: plitva geotermalna energija, odprti geotermalni sistemi, podzemna voda, kemicna sestava, toplotna crpalka Abstract Shallow geothermal energy is a renewable source of energy that can be used effectively with open loop geothermal systems. Knowledge of hydrogeological conditions is a prerequisite for the successful implementation and operation of such systems. The article describes a risk assessment of open loop geothermal system operation related to the chemical composition of groundwater in the area of the City of Ljubljana. Results of the study show that in the area of the Ljubljansko polje aquifer, the geochemical characteristics of the groundwater do not represent a risk of possible operational problems for an open loop geothermal system. On the contrary, the chemical composition of the groundwater in the Ljubljansko barje aquifer indicates a risk of corrosion and/or the precipitation of minerals, which can lead to diminished efficiency of the geothermal system or even damage that can result in the interruption of operations. In order to avoid operational problems in open loop systems, wells must be a professionally designed and installed, and groundwater geochemical characteristics properly determined. In the latter, it is important to take into account the method of sampling, since the chemical composition of water in the aquifer and in the geothermal system may vary significantly. Izvlecek Plitva geotermalna energija je obnovljivi vir energije, ki ga lahko ucinkovito uporabljamo s pomocjo odprtih geotermalnih sistemov. Pogoj za njihovo uspešno namestitev in delovanje je poznavanje hidrogeoloških pogojev. Clanek opisuje oceno tveganja za delovanje odprtih geotermalnih sistemov, povezanih s kemicno sestavo podzemne vode na obmocju Mestne obcine Ljubljana. Rezultati raziskav kažejo, da na obmocju vodonosnika Ljubljanskega polja geokemicne znacilnosti podzemne vode ne predstavljajo posebnega tveganja za delovanje odprtih geotermalnih sistemov. Nasprotno na obmocju Ljubljanskega barja kemicna sestava podzemne vode nakazuje možnost korozije in obarjanja mineralov, kar lahko povzroci zmanjšanje ucinkovitosti odprtega geotermalnega sistema ali celo poškodbe, ki onemogocajo njegovo delovanje. Na tem obmocju je v izogib težavam pri delovanju tovrstnih sistemov nujno strokovno nacrtovanje in izvedba vrtine ter ugotovitev geokemicnih znacilnosti podzemne vode. Pri slednjem je pomembno upoštevati nacin vzorcenja, saj se kemijska sestava vode v vodonosniku in geotermalnem sistemu lahko bistveno razlikuje. Introduction the stable subsurface conditions and heat stored Shallow geothermal energy is a renewable in the solid rocks or groundwater for heating or source of energy with increasingly important cooling, and for seasonal energy storage (Bonte, environmental, economic and social impacts. 2015). There are two kinds of shallow geother-The subsurface temperature at a depth of 10 m is mal systems: closed and open loop (Fig. 1). Ge-practically constant throughout the year (roughly othermal open loop systems, which are the focus the annual average ambient temperature). Shal-of this study, use groundwater as a conveyor or low geothermal systems can take advantage of carrier of heat. Such systems consist of extrac­tion and injection wells and transfer withdrawn groundwater to a heat exchanger, and after ex­ploitation it is reinjected back into the aquifer. The direct use of groundwater, which is a good carrier of thermal energy due to its high specif­ic heat capacity, makes open loop systems more efficient in general than closed loop systems (Internet 1), which use a mixture of water and antifreeze with lower specific heat capacity and exchange heat with subsurface through a poly­ ethylene pipe. Specific heat capacity of the water and antifreeze mixture decreases as the amount of the volume of antifreeze used in mixture in­creases (Roslan et al., 2017). On the other hand, the installation and oper­ation of open loop systems is more challenging. The first condition for the implementation of an open loop system is the availability of groundwa­ter, whereby the hydrogeological conditions can enable the withdrawal and injection of a suffi­cient quantity of groundwater (or required flow rate). Furthermore, the aquifer may already be used for other priority purposes (e.g. drinking water supply) or may be protected (e.g. nature protection area). The use of shallow geothermal energy with open loop systems affects the local hydraulic regime and temperature of groundwa­ter which can potentially mobilise contaminants and influence physical properties of groundwater, chemical reactions, microbiology and the inter­action of these factors with each other (Zuurbier et al., 2013). Due to these risks and risk related to drilling of boreholes, installation of shallow geothermal systems within catchments of drink­ing water well is often restricted (Zuurbier et al., 2013). Böttcher et al. (2019) outlined the physical, operational and regulatory limits of such, and stressed the fact that detailed knowledge of the local hydrogeological conditions and the result­ing technical potential are crucial conditions for the efficient use of open loop systems. Another important factor, which is investigated in this study, is the chemical composition of groundwa­ter, which can introduce problems into open loop systems, namely clogging or corrosion, or both (Rafferty, 1999). The precipitation of minerals can serious­ ly affect the efficiency of the well and all other installations exposed to groundwater with low dissolved oxygen concentrations (Houben, 2003). When the screen section of the well is clogged with precipitated minerals, the amount of water that can flow into the well decline and thus the well’s capacity decreases (Woyessa, 2011). The development of incrustation in wells can be the result of both chemical and biological processes (Park et al., 2015). Chemical encrustation could be the secondary effect of biofouling oxidation or corrosion (Smith & Tuovinen, 1985). Changes in O2 and CO2 con- Fig. 1. Scheme of shallow geothermal energy systems, used for heating and cooling of buildings (Internet 1). tent in groundwater, as well as in pressure and temperature, can lead to the formation of car­bonate and silica minerals, as well as iron and manganese containing minerals (Abesser, 2010; Brons et al., 1991; Holm et al., 1987; Rafferty, 1999). Minerals containing iron, such as Fe(OH)3, goethite (FeOOH) and hematite (Fe2O3) can be precipitated as scale within the open loop system (Park et al., 2015). The Langelier Saturation In­dex (LSI) and Ryznar Stability Index (RSI) are often used as an indication of the aggressiveness of the water and the risk of the precipitation of carbonate minerals inside the open loop system (Rafferty, 1999). If under natural conditions the oxygen con­centration in groundwater is low and the pH val­ue ranges from 6.5 to 7.5, iron occurs primarily as dissolved ferrous iron (Fe2+). Fe2+ is unstable in contact with oxygen, and in the presence of air it changes to insoluble ferric iron (Fe3+) and precipitates as ferric oxide or oxyhydroxide. The oxidation rate of Fe2+ is highly dependent on pH conditions (Woyessa, 2011) and dissolved oxy­gen concentrations (Donald, 1997). When water is aerated, almost all the iron becomes insol­uble. This condition can arise from the mixing of groundwater with low dissolved oxygen con­centrations with oxygen rich groundwater dur­ing operation of the well (Donald, 1997). Ferric oxides and oxyhydroxides precipitate and coat surrounding surfaces. This process also results in rust on metal surfaces exposed to the atmos­phere. If Fe2+ is combined with carbonate ions, iron bicarbonate is formed. Manganese resembles iron in its chemical behaviour and occurrence, but in groundwater it is less abundant than iron (Kemmer, 1977). Indicators of incrusting ground­water are high pH value (> 7.5), RSI < 7, iron con­tent > 0.5 mg/L (precipitation of iron), carbonate hardness > 300 mg/L (precipitation of calcium carbonate), manganese content > 0.2 mg/L (pre­cipitation of manganese) and the presence of oxy­gen (Driscol, 1986; Gtzl et al., 2018). Clogging can also occur due to the presence of iron bacteria, which form biological incrusta­tions (Smith & Tuovinen, 1985). Iron bacteria’s natural environment is wetlands (Pringsheim, 1949), where they mainly generate most of their energy for metabolism by oxidising soluble Fe2+ into insoluble Fe3+, and in this way gain a small amount of energy by utilising large amounts of Fe2+ (Howsam, 1988). Beside the clogging, another risk for open loop systems is corrosion, which is the result of chemi­cal and electrochemical processes. Chemical cor­rosion can be expected if the water has a low pH value (< 7), elevated concentrations of dissolved oxygen (> 2 mg/L), hydrogen sulphide presence (even less than 1 mg/L), high TDS concentration (> 1000 mg/L), CO2 concentrations > 50 mg/L and chloride content > 500 mg/L (Driscoll, 1986). Electrochemical corrosion can occur when two conditions are fulfilled: an electrical potential difference on metal surfaces, and enough dis­solved solids in water to constitute a conductive fluid (electrolyte). An electrical potential differ­ence may develop between two different kinds of metals, or between proximate yet separate areas on the surface of the same metal (Driscoll, 1986). Corrosion can cause damages (new openings) in the open loop system: the enlargement of well screen openings and increased entry of finer ma­terial into the well are particularly common, and can harm the pump and reduce the efficiency of the well (Driscoll, 1986). Due to corrosion in an ionizing solvent the metal ion initially goes into solution but may then undergo a secondary reac­tion, combining with other ions present in the en­vironment to form an insoluble molecular species such as rust (Schofield, 2002). In this study a risk assessment of the efficient operation of open loop geothermal systems, relat­ed to the chemical composition of groundwater is presented. The study follows a procedure, devel­oped within the GeoPLASMA-CE project (Gtzl et al., 2018) which was implemented in the Lju­bljana pilot area. The procedure consists of three main steps. 1) Calculation of LSI and RSI indices using available archive data on chemical compo­sition of groundwater. 2) Additional field meas­urements and chemical analysis of groundwater in those areas where in the previous step a risk was identified and operational problems in open loop systems were reported. Different sampling procedures (in wells and from the system) were implemented and analysed in this step. 3) Outlin­ ing areas with a risk for the efficient operation of open loop geothermal systems. Hydogeological setting The study area is part of the area of Munic­ipality of Ljubljana, with aquifers potentially suitable for implementation of open loop systems: the Ljubljansko polje unconfined aquifer and the northern part of the Ljubljansko barje confined aquifer system (Fig. 2). The average annual pre­cipitation in this area is 1383 mm (2001–2010) while the average annual ambient temperature is 11.3 °C (2001–2010) (Internet 2). Fig. 2. Study area with locations of measurements. The Ljubljansko polje aquifer is composed of permeable gravel and sand beds with lenses of conglomerate. Due to its great thickness (which exceeds 100 m in the deepest parts) and high per­meability, this Quaternary aquifer contains sig­nificant quantities of groundwater, which is the main source of public water supply for the City of Ljubljana (Janža, 2009; Šram et al., 2012). The Ljubljansko barje aquifer is composed of alter­nating fluvial and lacustrine deposits with a het­erogeneous composition (silt, clay, sand, gravel) (Mencej, 1988/89). The top low-permeable layer in the northern part of the Ljubljansko barje is 10–20 meters thick (Fig. 3, A). Under this layer the heterogeneous and low permeable upper Pleistocene aquifer (Fig. 3, B) is situated. Beneath the upper Pleistocene aquifer, a thick silty and clayey layer (Fig. 3, C) is pres­ent and underneath the lower Pleistocene aquifer (Fig. 3, D), which consists of gravel and contains good quality groundwater (Prestor & Janža, 2002). It is a confined or semi-confined aquifer with artesian to sub-artesian conditions. Research of the Barje landfill influence on groundwater has revealed a reducing environ­ment and presence of iron, manganese, ammoni­um and arsenic in groundwater (Prestor & Janža, 2002). This influence of the landfill overlaps with the natural reduction environment and the con­sequences of reducing conditions resulting from the immission of pollution from other sources in the urbanized area (Prestor & Janža, 2002). The Sava River, which recharges the Lju­bljansko polje aquifer in its north-western part, has an electrical conductivity around 300 µS/cm (Jamnik et al., 2014). The low electrical conduc­tivities, between 200 and 300 µS/cm, and fluctu­ating temperatures at the north-western part of the Ljubljansko polje aquifer (Klece and Jarški prod well fields) are therefore the result of a sig­nificant recharge of the Sava river (Jamnik et al., 2014). Under highly urbanized parts of the Ljubljana polje aquifer, electrical conductivity ranges between 500 and 700 µS/cm. The temper­ature of the groundwater at the Ljubljansko polje range between 10.6 and 14.6 °C, while in the Lju­bljansko barje the temperature rises up to 15.6 °C (Janža et al., 2017). According to the archive and publicly acces­sible data (Internet 3), 93 open loop geothermal systems (December 2018) are installed in the Ljubljana pilot area. Problems in the operation of open loop systems, that could be related to groundwater chemical composition, were re­ported from the users from northern part of the Ljubljansko barje. The most commonly reported problems consist of deposition of iron minerals on filters which requires frequent cleaning in or­der to maintain system efficiency (Fig. 4). Materials and Methods Archive data processing The first step of the investigation involved the analysis of existing data on groundwater field parameter measurements and chemical analy­sis. The main body of said data was collected and organized from previous projects (AMIIGA, INCOME). Additional data from the nation­al monitoring program, accessible through a portal (Internet 4), were used in the analysis. The datum consist of measurements for ba­sic chemical parameters (anions and cations), which were used to determine the type of wa­ter and the ion balance (software AquaChem 2014.2.; Waterloo Hydrogeologic, 2018) for each observation point. The LSI was calculated using readings for alkalinity, hardness, TDS, pH and temperature (Lentech, 2018a). The groundwater electrical conductivity of unpolluted groundwater is usual­ly correlated with the concentration of dissolved carbonates in the water or the carbonate hard­ness of the water. If LSI < 0 the water is undersat­urated with calcium carbonate and has a tenden­cy to remove the existing protective coatings of calcium carbonate in pipelines and equipment (is corrosive); and if LSI > 0 the water is supersatu­rated with respect to calcium carbonate (CaCO3) and the formation of scale may occur (Gonzalez et al., 2019). Additional field measurements and groundwater sampling Additional groundwater sampling and field measurements were focused on the northern part of the Ljubljansko barje, where operational prob­lems of open loop systems related to the chemical composition of groundwater were reported. Since the number of locations, where the sampling could be performed from wells was limited, sam­pling was performed also on the surface part of the open loop systems, where water samples were taken from the heat pump system taps. A total of four observation wells and eight open loop sys­tems were selected. In order to assess the material resistance of open loop systems, two sampling campaigns were carried out. First sampling on all 12 sam­pling locations was performed in March 2018. A second sampling in May 2018 was repeated in three wells (LJ1, LJ2 & LJ6) and on one tap (LJ3) in order to analyse the comparability of results of chemical analysis of samples taken on different object types in different time periods. Groundwater sampling on wells was performed on 27th March and 14th May using a Grundfos M1 submersible pump (Eijkelkamp, 2017). Wells LJ2 (depth: 84 m), LJ4 (depth: 92 m), LJ5 (depth: 92 m) and LJ6 (depth: 72 m) are observation wells, while LJ1 (24 m) is an injection well and is part of an open loop system. In other cases, wa­ter samples from open loop systems were taken from taps. Field parameters such as pH, electri­cal conductivity (Cond.), temperature (T), redox potential (Eh), dissolved oxygen (DO) and oxygen saturation (O2) were measured with a portable WTW Multimeter pH/Cond (pH value: SenTix 42, Cond. and T: TetraCon 325 (WTW GmbH, 2004) and with WTW Multi 3410/set C (redox potential: Sentix ORP (WTW GmbH, 2008), oxygen content: FDO 925 (WTW GmbH, 2010). Fe2+ and Fe (total) content in water was measured with a HACH DR 2800 portable spectrophotometer (Hach Lange, 2012). Analysis of major cations (Na+, K+, Ca2+, Mg2+; SIST EN ISO 14911:2000), anions (Cl-, SO42-, NO3-; SIST EN ISO 10304-1:2009; and HCO3-; ASTM D 1067-B mod.), and Fe total (SM.3500­Fe-B) (if the value in the field was above 3 mg/L) were performed by the accredited Vodovod-Ka­nalizacija d.o.o. laboratory. Additional samples for analysis of Mn (ISO 17294-2:2016(E), NM) and dissolved sulphide (as H2S – SIST ISO 10530: 1996, NM) content were also taken and analysed in Vodovod-Kanalizacija d.o.o. laboratory. Un­certainties of measured contents are in following - ranges: for HCO3 ±0.02 mg/L, Fe total (measured in laboratory) ±0.14 mg/L, Mn ±0.016 mg/L and for dissolved sulphide ±0.014 mg/L (Auersperger & Železnik Bracic, 2018). Results and discussion Archive data processing Data from 126 locations, 91 from the area of the Ljubljansko polje aquifer and 35 from the area of the Ljubljansko barje aquifer, were an-alysed. The data consist of total 2227 analysis of chemical parameters, performed between the years 2008 and 2017. 28.7 % of the data includ­ed in the data processing procedure contain no - data on NO3 content; therefore, a calculation for ion balance could not be performed. On the rest of the data, accuracy check was made using an AquaChem 2014.2, which indicated that 15.5 % of the data showed poor ion balance, 11.6 % fair and 44.2 % good ion balance. The most common water type in both aquifers is Ca-Mg-HCO3. Based on the calculated LSI in the study area, the risk of the formation of lime scale (where median LSI is > 0) and/or corrosion is present (where median LSI value is < 0) (Fig. 5). Accord­ ing to the distribution of electrical conductivity in the Ljubljansko polje and Ljubljansko bar-je aquifer, figure 5 shows the risk of corrosion or limescale formation, but since the expected changes in groundwater temperature in shallow, low-temperature open loop geothermal system is less than 5°C, such risk is low (VDI-Richtlinien, 2001). The RSI is influenced by pH value, electrical - conductivity, Ca2+, HCO3 and water temperature (Lentech, 2018b). Based on calculations of RSI, very aggressive groundwater was identified in Fig. 5. Risk of corrosion or formation of limescale in the case of .T of groundwater > 5 °C. Fig. 6. Groundwater aggressiveness based on RSI. Fig. 7. Risk of metal corrosion, due to high SO42- and DO content. the Ljubljansko barje aquifer (Fig. 6), where the minimum pH value (6.8) is noticeable lower than in Ljubljansko polje aquifer (7.3). RSI value higher than 7.5, pH value < 7.5 and presence of dissolved oxygen (> 2 mg/L) in groundwater indicate the risk of metal corrosion mainly in the Ljubljansko barje aquifer (Fig. 7). Since archive data on iron and manganese content are scarce it was not possible to assess the risk of iron and manganese precipitation: therefore, additional sampling was carried out. Additional field measurements and groundwater sampling Results of the field measurements and chem­ical analyses of samples taken from wells and from taps (open loop systems) are presented in (Table 1). In order to determine the risk in rela­tion to the chemical composition of groundwater for the operation of open loop systems, the re­sults of field measurements and chemical anal­yses were compared with parameter limits. They are recommended by heat pump manufacturers Ochsner Wärmepumpen GmbH, Viessmann Ltd. and Dimplex Ltd (Kmiecik et al., 2017) and rep­resent conditions required for the undisturbed and efficient operation of open loop systems. A conservative approach was used, and most re­strictive limits of the mentioned manufacturers were considered (Table 1). Results of the analysis (Table 1) show that manufacturers’ requirements could not be met in all cases. There is no risk of corrosion at four locations (Table 1; LJ3, LJ7, LJ8 and LJ9), which can occur at eight locations (Table 1; LJ1, LJ2, LJ4, LJ5, LJ6, LJ10, LJ11 and LJ12). Due to the high iron and dissolved oxygen content at five locations a risk of iron or manganese scaling is indicated (Table 1; LJ1, LJ4, LJ5, LJ6 and LJ-12). To mitigate this kind of risk filtration after oxi­dation (Appelo & Postma, 2005) was reported as most cost-effective method for removal of iron or manganese scaling from the system (Power & Prasad, 2010). The central part of the Ljubljansko barje con­ fined aquifer is covered with a thick layer of clay, which causes lower oxygen content in ground­ water. Oxygen deficiency creates hydrochemical conditions in which iron and manganese, usually present in poorly soluble chemical forms, become mobile (Jamnik et al., 2014). Based on the analy­ses of archive data and the results of additional measurements, including knowledge of natural hydrogeological conditions we identified metal corrosion and iron or manganese scaling as the highest risk to the efficient operation of open loop systems (Table 1) and outlined the area with the highest risk (Fig. 8). Comparison of different sampling approaches A comparison of the results of different sam­pling approaches (Table 2) shows that the values of parameters measured on different dates do not differ noticeable for the samples on locations LJ2, LJ3 and LJ6, when the samples taken from the same object type (well or heat pump tap). At location LJ-1, samples were taken one time from the well and one time from the tap, but at dif­ferent times. Due to the different sampling peri­ods, direct comparison is questionable; however, taking into account the results of measurements taken at other locations, it seems that sampling from different types of object produces the high­est differences in measured parameters and re­flects the different conditions in the geothermal system and in the well, or before and after heat extraction. The most noticeable differences are observed in the values of parameters dissolved oxygen (3.38 and 0.71 mg/L), electrical conduc­tivity (676 and 483 µS/cm), and concentration - of HCO3 (289 and 355 mg/L). Heat extraction results in lower water temperatures in the in­jection well (10.1 °C) than at the tap (13.0 °C). However, for more detailed comparison of two sampling approaches, more data would have to be collected. Since no data on the iron content of groundwater sampled from well are available (only at tap), no interpretation of the processes that occur during heat extraction within the sys­tem is possible. Conclusion Based on archive data, the calculated values of LSI and RSI indicate potential risk of lime scale formation and/or corrosion in both aquifers. But since for shallow geothermal open loop systems expected changes in groundwater temperature are smaller than 5 °C, this kind of risk is low. Archive data on groundwater composition in the Ljubljansko polje aquifer show a high concen­tration of dissolved oxygen (on average 7.67 mg/L) and low iron content (on average 0.09 mg/L of Fe2+), thus the risk of iron precipitation is low. In contrast, in the confined aquifer of the Ljubljan­sko barje the concentrations of iron are elevated (> 0.2 mg/L) and risk of iron precipitation was Tabl e 1. Comparison of addit ional fi eld measurements and chemical analy ses (diff erent sampli ng dates) wit h li mit ations of the install ation, as indi cated by heat pump manufacturers (Kmiecik et al., 2017) LJ12 RISK HP tap 28 th March 2018 – 0 0 – 0 + + + - May lead to corro­sion and installationisn’t recom­mended Possible – Fe, Mn, DO Value 703 7.23 7.28 2.14 415 22.1 30.3 <2.2 0.23 LJ11 RISK HP tap 28 th March 2018 + + - + + + + + + Installationisn’t recom­mended Low risk - low Fe, Mn concentra­tions Value 389 7.77 9.91 0.01 229 7.05 14.3 4.12 <0.0001 LJ10 RISK HP tap 28 th March 2018 + + 0 – + + + + + May lead to corro­sion and installationisn’t recom­mended Low risk - low Fe, Mn concentra­tions Value 380 7.58 5.52 0.025 243 9.03 8.26 4.92 <0.0001 LJ9 RISK HP tap 28 th March 2018 + + 0 + + + + + + No problems expected Low risk - low Fe, Mn concentra­tions Value 461 7.68 5.88 <0.03 270 8.49 19.6 4.87 0.0001 LJ8 RISK HP tap 28 th March 2018 + + 0 + + + + + + No problems expected Low risk - low Fe, Mn concentra­tions Value 463 7.56 7.47 <0.03 268 10.5 21.5 5.18 0.0003 LJ7 RISK HP tap 28 th March 2018 + + 0 + + + + + + No problems expected Low risk - low Fe, Mn concentra­tions Value 340 7.65 4.87 0.13 221 5.98 4.95 <2.2 0.0006 LJ6 RISK Well (depth: 72 m) 14 th May 2018 + + 0 / + + + + / No problems expected / Value 417 7.6 3.79 / 261 11.9 12.6 5.98 / RISK 27 th March 2018 + + 0 – + + + + + May lead to corrosion and installationisn’t recom­mended Possible – pH, DO, Fe Value 375 7.51 1.64 0.855 253 10 13.5 5.09 0.012 LJ5 RISK Well (depth:92 m) 27 th March 2018 – + + – + + + + - May lead to corrosion and installationisn’t recom­mended Possible – Fe, pH – if aerated Value 502 7.81 0.08 3.11 265 <1.5 50.2 <2.2 0.13 LJ4 RISK Well (depth:92 m) 27 th March 2018 – 0 0 - 0 0 + + - May lead to corrosion and installationisn’t recom­mended Possible – high Fe, DO Value 1024 7.12 2.51 2.28 466 75.4 79.3 <2.2 0.06 LJ3 RISK HP tap 14 th May 2018 + + 0 / + + + + / No problems expected / Value 345 7.57 6.21 / 286 22.4 4.16 <2.2 / RISK 28 th March 2018 + + 0 + + + + + + No problems expected Low risk - low Fe, Mn concentra­tions Value 438 7.68 6.81 <0.03 260 21.9 4.59 <2.2 0.029 LJ2 RISK Well (depth: 84 m) 14 th May 2018 + 0 0 / + + + + / May lead to corrosion / Value 463 7.5 5.51 / 253 18.1 27 7.17 / RISK 27 th March 2018 + 0 0 + + + + + + May lead to corrosion Low risk - low Fe, Mn concentra­tions Value 491 7.1 5.7 <0.03 231 18.5 28.9 7.17 <0.0001 LJ1 RISK Well (depth:24 m) 14 th May 2018 + 0 0 / 0 + + + / May lead to corrosion / Value 483 7.33 0.71 / 355 16.1 53.4 2.26 / RISK HP tap 28 th March 2018 – 0 0 - + + + + - May lead to corro­sion and installationisn’t recom­mended Possible – high Fe, DO Value 676 7.28 3.38 2.2 289 15.5 53.8 <2.2 0.06 Limit value <10 10 - 500 >500 <7.5 7.5 - 8 >8 <0.2 0.2 - 8 >8 <0.2 >0.2 <70 70 - 300 >300 <50 50 - 100 >100 <100 100 – 200 >200 <100 >100 <0.05 >0.05 Corrosion Scaling – iron/manganese Risk* 0 + – 0 + – + 0 – + – 0 + 0 + 0 – + 0 – + 0 + - Parameter Sampling date Cond. [mg/L] pH value DO [mg/L] Fe [mg/L] -HCO3 [mg/L] 2­SO 4 [mg/L] Cl ­ [mg/L] -NO 3 [mg/L] Mn [mg/L] Risk • (0) may lead to corrosion, when two or more parameters are exceeded •(-installation isn’t recommended, if one of the parameter’s limit is exceeded) • (+) material is usually resistant Fig. 8. Outline of area with risk of metal corrosion or iron and/or manganese scaling. Table 2. Comparison of results of field parameter and chemical parameter measurements at tap or in well (March 27th, March 28th and May 14th, 2018). Location LJ1 LJ2 LJ3 LJ6 Object type tap well well well tap tap well well Sampling date 28th March 14th May 27th March 14th May 28th March 14th May 27th March 14th May T [°C] 13.0 10.1 12.2 11.5 13.3 13.1 13.1 12.5 Cond [µS/cm] 676 483 491 463 438 345 375 417 pH value 7.28 7.33 7.10 7.50 7.68 7.57 7.51 7.6 Eh [mV] 229 216 363 353 400 332 96 175 DO [mg/L] 3.38 0.71 5.7 5.51 6.81 6.21 1.64 3.79 O [%] 2 33.4 55.0 52.2 67.5 60.8 17 36.6 Fe2+ [mg/L] 0.27 / <0.03 / <0.03 / 0.186 / Fe tot [mg/L] 2.2# / <0.03 / <0.03 / 0.855 / HCO- [mg/L] 3 289 355 231 253 260 286 253 261 K+ [mg/L] 1.1 0.83 0.48 0.51 0.79 0.66 1 0.97 Ca2+[mg/L] 81 83 88 88 56 58 54 60 Mg2+[mg/L] 34 34 12 12 25 25 22 23 SO2-[mg/L] 4 15.5 16.1 18.5 18.1 21.9 22.4 10 11.9 Cl­ [mg/L] 53.8 53.4 28.9 27.0 4.59 4.16 13.5 12.6 NO3-[mg/L] <2.2 2.26 7.17 7.17 <2.2 <2.2 5.09 5.98 Suspended solids [mg/L] 44 / <10 / <10 / 26 / Mn [mg/L] 0.06 / <0.0001 / 0.029 / 0.012 / S diss. [mg/L] <0.05 / <0.05 / <0.05 / <0.05 / # - measured in laboratory (in-situ > 3 mg/L) Italic – Comparable data (<10 % difference between measurements) Bold –Noticeable difference between measurements (>40 % difference) identified in the area of Ljubljansko barje aqui­fer. Taking into consideration these results and the hydrogeological conditions, the area with a high risk of threat to the efficient operation of open loop systems in the study area was outlined. Additional measurements at the Ljubljansko barje indicate that the known operational prob­lems of open loop systems are the consequence of manganese or/and iron precipitation. Higher sul­phate and dissolved oxygen content also indicate corrosive groundwater. When compiling infor­mation on the chemical composition of ground­water in the aquifer, it must be taken into consid­eration that samples of water taken from the open loop system (from a tap) do not always represent the content of dissolved oxygen in groundwater of the aquifer. Due to the lack of data on the iron content of groundwater sampled from well, no interpretation of the processes that occur during heat extraction within the system was possible. This important issue should be addressed in fol­lowing investigations. Operational problems of open loop geothermal systems related to scaling or corrosion are most often the consequence of the fact that geother­mal systems are installed without consideration of the chemical composition of the groundwater and hydrogeological conditions in general. In such cases mitigation measures are required in order to ensure the efficient operation of open loop systems. The findings of this study underpin the impor­tance of knowledge of the hydrogeological condi­tions and the composition of groundwater before the installation of an open loop system. Only a combination of said knowledge and proper con­sideration of the parameter limits recommended by heat pump manufactures can ensure the op-timised, site specific selection, installation and efficient operation of geothermal systems. Acknowledgments The authors acknowledge the project GeoPLASMA-CE co-financed by Interreg CENTRAL EUROPE Programme, project MUSE (GeoERA) whi­ch has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 731166, and the financial support from the Slovenian Research Agency (rese­arch core funding No. P1-0020). The authors wish to thank Dejan Šram and Simona Adrinek for graphical work and help in cartography. 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CC Atribution 4.0 License https://doi.org/10.5474/geologija.2019.012 Statistical analysis of groundwater drought on Dravsko-Ptujsko polje Statisticna analiza suše podzemne vode na primeru Dravsko-Ptujskega polja Simona ADRINEK1 & Mihael BRENCIC2,1 1Geological Survey of Slovenia, Dimiceva ulica 14, SI-1000 Ljubljana, Slovenia; e-mail: simona.adrinek@geo-zs.si 2University of Ljubljana, Faculty of Natural Sciences and Engineering, Department of Geology, Aškerceva cesta 12, SI-1000 Ljubljana, Slovenia Prejeto / Received 8. 10. 2019; Sprejeto / Accepted 12. 12. 2019; Objavljeno na spletu / Published online 24. 12. 2019 Key words: definition of groundwater drought, Standardized Groundwater Index - SGI, intergranular porosity, unconfined aquifer Kljucne besede: definicija suše podzemne vode, standardizirani indeks podzemne vode - SGI, medzrnska poroznost, odprt vodonosnik Abstract Drought is a complex phenomenon and can be defined in many ways. It is a globally growing problem that occurs on a time scale ranging from months to years. There are several types of drought, but the least investigated is groundwater drought. Globally, research on it started relatively recently, in the last decade. In Slovenia, there are almost no data on groundwater drought. In this research, we focused on statistical analysis of groundwater level diagrams of individual groundwater stations, which can determine periods of groundwater drought. The first method used is based on ranking statistics defined by lower percentiles that indicate low groundwater level. Another approach was based on univariant Standardized Groundwater Index – SGI. As a case study, the unconfined Quaternary aquifer of Dravsko-Ptujsko polje was chosen. The results show that the groundwater deficits in the groundwater stations appear simultaneously but differ in intensity and duration of each drought period. The important conclusion is that the intensity of groundwater drought does not depend on the length of an event but more on thickness of the unsaturated aquifer zone. Also, groundwater stations located on the western rim below Pohorje Mountains have a higher amplitude of groundwater fluctuations than the others. The result of this are more intensive dry periods with longer duration. On the other hand, we have locations in the central and eastern part of the Dravsko-Ptujsko polje with more damped fluctuation, which leads to less intensive but more frequent groundwater drought events. Izvlecek Suša je pojav, ki v svetovnem merilu predstavlja vedno vecji problem. Poznamo vec vrst suš, med katerimi je najslabše razumljena suša podzemne vode. Z raziskavami suše podzemne vode se je hidrogeologija zacela intenzivneje ukvarjati šele v zadnjem desetletju. Za obmocje Slovenije skorajda nimamo podatkov o suši podzemne vode. V tej raziskavi smo se osredotocili na statisticno analizo diagramov nihanja gladin podzemne vode v posamezni opazovalni vrtini, s katerimi lahko dolocimo sušna obdobja. Prva metoda temelji na vrstilni statistiki, doloceni z najnižjo percentilno vrednostjo niza meritev obravnavane opazovalne vrtine. Druga metoda uporablja univariatni indeks podzemne vode – SGI. Za pilotno obmocje je bil izbran odprti kvartarni vodonosnik Dravsko-Ptujskega polja. Rezultati so pokazali, da se primanjkljaj podzemne vode pojavi na razlicnih mestih skoraj hkrati, a se razlikuje v intenziteti in trajanju posameznega sušnega pojava. Opazovalne vrtine, ki se nahajajo na zahodnem obrobju pod Pohorjem imajo višje amplitude nihanja podzemne vode kot vrtine v osrednjem delu Dravsko-Ptujskega polja, kar je pogojeno z vecjo debelino nezasicene cone vodonosnika. To vpliva na bolj intenzivna sušna obdobja z daljšim trajanjem. Na drugi strani imajo opazovalne vrtine v osrednjem in vzhodnem delu Dravsko-Ptujskega polja bolj dušeno nihanje gladine podzemne vode, kar povzroci manj intenzivna, a bolj pogosta sušna obdobja. Introduction Even though Slovenia is a water-rich country, several drought events appeared in the recent past (in years 2003, 2012, 2013, 2017), which had substantial impact on national economy (Sušnik & Gregoric, 2017; Flis, 2017). By some climat­ic models, it is also predicted that in the future drought will be a more frequent event (Andjelov et al., 2016). The most important drought recog­nized in Slovenia is agricultural drought, which is usually explained as a meteorologically driven drought event. Not much is known about other droughts, among which groundwater drought can be very important. In everyday life, attention is usually paid to meteorological and agricultur­al drought, because their influence is immediate and visible to everybody. As well as in other re­gions around the world, in Slovenia, extensive research has been performed on drought and several results regarding drought are rising sig­nificantly, but there was not much effort put in the research of groundwater drought. Research on the latter started only recently and not so many results of it are published. Due to the role of groundwater in Slovenian economy, ground­water drought can have important consequences. From that point, the question how groundwater drought is influencing general water availability in water cycle and overall groundwater manage­ment can be raised. In Slovenia, monitoring of groundwater quan­titative status is well established (Andjelov et al., 2006). In some of the alluvial aquifers, the monitoring network is relatively dense and en­ables detection of local trends of decrease or in­crease of groundwater levels, which can be taken as indicators of groundwater storage change in the aquifer. Based on groundwater monitoring results and with the application of methodology for groundwater drought detection, it would be possible to optimize groundwater management in relation to extreme event appearance. This paper aims to investigate available defi­nitions of groundwater drought and possible in-dices from the literature. Based on the collected information, it was intended to define a drought indicator suitable for analysing the effects of drought in north-eastern Slovenia. In the second step, the intention was to compare meteorological and groundwater droughts. As a case study, the unconfined Quaternary aquifer of Dravsko-Ptu­jsko polje was chosen. The area was chosen due to the availability of relatively long and continuous set of groundwater measurements on 22 ground­water stations as well as due to the natural char­acteristics of the aquifer, which is well drained and its response to the underground water short­age is relatively rapid. The analysis performed was phenomenological; during the interpretation of the calculated indices, several questions arose in relation to groundwater level time depended trends. These questions remain to be open due to their complexity, which goes over the scope of the paper. Methods Groundwater drought definitions There is no uniform and widely accepted defi­nition of groundwater drought. Most of the avail­able definitions rely on the fact that groundwater drought appears with a decrease of groundwater or piezometric level in the aquifer. This decline and consequent drought can be a consequence of natural or anthropogenic factors (Haas & Birk, 2017, Namdar Ghanbari & Bravo, 2011); there­fore, we can have natural groundwater droughts and anthropogenically induced groundwater droughts. One of the possible approaches to define groundwater drought is a statistical analysis of groundwater level fluctuation that is described as time series measured in individual groundwater stations, which is indicated through a decrease of groundwater or piezometric level. Two possi­ ble groups of measures can be applied; the first is based on ranking statistics of groundwater meas­urements, and the second is based on groundwa­ter drought indices. Their application is similar to other indices applied in studies of meteoro­logical and hydrological droughts (Dracup et al., 1980; Palmer, 1965; Vicente-Serrano et al., 2010; Brencic, 2016). For both groups of measures, groundwater drought is defined when values are smaller than the critical measure. The first method is ranking statistics, defined by percentiles when groundwater level in the aquifer falls below the critical value in a given period (Van Lanen & Peters, 2000). Critical val­ue is defined as a selected percentile of all meas­urements and is usually based on socioeconomic or environmental aspects (Hisdal & Tallaksen, 2000). Studies of various drought aspects in Slo­venia showed that, for a reliable drought esti­mate, at least 30-year series of continuous meas­urements are needed (Kobold et al., 2012). Three useful critical drought percentiles were defined: percentile ..25 is a critical value when intensive monitoring of drought starts, percentile ..10 isa critical value when the drought warning starts, and percentile ..5 represent onset of protection measures (Kobold et al., 2012). The same percen­tiles were used in our study. The second method is based on groundwater drought indices, which are based on similar defi­nitions as meteorological drought indices. In our study, we have applied Standardized Groundwa­ter Index - SGI (Bloomfield & Marchant, 2013), which is based on groundwater level measure­ments. For representation of SGI, a proper se­lection of the time window is necessary. Its cal­culation depends on the available time series of groundwater measurements. For a sufficiently long measurement period where we want to de­termine the regional prevalence of drought (more than 30 years), it is more appropriate to use an­nual data of the selected parameter; while for a shorter period of time (less than 30 years), it is more appropriate to use the monthly values of the selected parameter, which give more precise local values (Mishra & Singh, 2010; Brencic, 2017). In our study, results of groundwater drought calculations were also compared with meteoro­logical drought indices. As an indicator of me­teorological drought, Standardized Precipita­tion Index – SPI was used (McKee et al., 1993). This is a univariate index where the only input parameter is precipitation. Its application is be­coming more and more established, since it can quantify drought periods with a deficit or excess of precipitation at different time scales (Gregoric & Ceglar, 2017; Ceglar & Kajfež-Bogataj, 2008; Sušnik & Pogacar, 2010; Sušnik, 2014; Brencic, 2016; Haas & Birk, 2017). It is based on the long­ term average of the rainfall amount, which is of­ten considered as a monthly value. Statistical methods Statistical analyses were carried out on public domain monitoring sites operated by the Agen­cy for the Environment of RS (ARSO, 2018). Data were taken from 4 precipitation stations and from 22 groundwater stations (Fig. 1). The daily groundwater level data were calcu­lated to average monthly values, for which the continuity and density at individual groundwa­ter station were analysed. Some of them were omitted due to inadequate measurements or were corrected with linear interpolation. Since the time series of the available data sets among the groundwater stations are not the same, we have chosen four different time intervals that cover the different measuring ranges. Groundwater level data were analysed with frequency distri­bution parameters where we described the prop­erties of the data with respect to shape, position, and dispersion. With time series diagrams, we detected anom­alous groundwater level trends that can influence stationarity required for frequency analysis. Such stations were omitted from further analy­sis. Data were also analysed on a normal prob- Fig. 1. Dravsko-Ptujsko polje groundwater and precipitation station locations (cartographic basis Geodetska uprava Republike Slovenije, DPK750, 2017). ability plot where the extreme values (i.e. floods, droughts) are clearly visible, since the deviations of the lowest and highest values of the actual measurement curve are clearly separated from the theoretical curve. For further calculations, we checked the prob­ ability distribution of groundwater levels. We used the Kolmogorov-Smirnov test, which is a non-parametric test for continuous probability distributions. It is based on the deviation of the distance between the distribution function and the comparative distribution function, which is then compared with the tabulated critical value (McKillup & Darby Dvar, 2010). We also checked the measurements of the theoretical distribution with the Anderson-Dar­ling test, which is suitable for testing contin­uous data and is based on a comparison of the empirical and theoretical distribution function (Stephens, 1974). It is a modification of the Kol-mogorov-Smirnov test and gives more weight to the tails. The equation of Anderson-Darling test is defined as: ........ ................ =-........-........1 .{(2........-1)ln........(................)+(2........+1-2........) ........=1 )ln(1-........(................-........+1)} (1) . sample size .(...) cumulative distribution function for the specified theoretical distribution .. the ith rank when the data is sorted in ascending order Ranking statistics of percentiles The first method used for the analysis of groundwater drought was based on ranking sta­tistics of percentiles, using the lowest 10 % of the measurements of an individual groundwater station – ..10. They were presented on a duration curve (Fig. 2), which shows the percentage of time in which the groundwater level was lower or equal to a certain limit value (Searcy, 1959). The values of the groundwater level were arranged in a descending order from 1 to . and the percent­age was ascribed according to the equation: ......... ........(%)=(2) .........*100 possibility that value exceed or is equal to a cer­ tain % of the time . ranked value of n data . number of all data Fig. 2. Schematic representation of groundwater level dura­tion curve. The critical limit value ..10 was used for the calculation of groundwater deficit D. The method for calculating D is based on the following equa­tion (Peters et al., 2005 & 2006) (Fig. 3): ................ ........ =. [........10 -................]................ ........0 (3) .0 start of the drought (day) .. end of the drought (day) ... data on interval between .0 and .. .10 threshold level value of observed data (m) The second method used for analysis of groundwater drought was based on index calcu­lations. We applied the concept of the SGI calcu­lation (Bloomfield & Marchant, 2013), which has the same logic as the SPI calculation (McKee et al., 1993). Calculation of standardized precipitation index – SPI SPI is a univariate index where the only in­put is precipitation data. The index represents the number of standard deviations of precipita­tion from the long-term average in the observed period. This applies only to normally (Gaussian) distributed precipitation, but this is not usually their characteristic. Therefore, the appropriate theoretical distribution must be first determined. The first step is to determine the probability density that describes the past series of precip­itation. This gives us a probability distribution of a continuous random variable for the selected time range of data. The range can be given for a different set of precipitation, for example, SPI1 (one month) and SPI3 (three months). The next step is to calculate the distribution function for the selected sum of precipitation that is normal­ized. The values obtained represent SPI (Table 1). The distribution, where the mean value is 0 and the standard deviation 1, is called the standard­ized Gaussian distribution (McKee et al., 1993). Fig. 3. Groundwater level fluctuations with drought parameters for groundwater station Gorišnica (1990–2016). The most common theoretical distribution used is the gamma distribution that needs to be mod­ ified, because it is not defined at a value of 0 but occurs often due to the absence of precipitation. Then the cumulative value is transformed into a Gaussian distribution (Thom, 1966; McKee et al., 1993). The gamma distribution of a given variable is defined as follows: 1 ................G(a)................-1........-................ = ................(........)(4) . > 0 shape parameter . > 0 scale parameter . > 0 precipitation amount .(.)=.0 8...1 ..... gamma function Table 1. SPI and SGI categories (after McKee et al., 1993). SPI values Drought category SGI values Drought category = 2.00 Extremely wet 1.50 to 1.99 Very wet Above 0 No drought 1.00 to 1.49 Moderately wet –1.00 to 0 Minimal drought –0.99 to 0.99 Near normal –1.50 to –1.00 Moderate drought –1.49 to –1.00 Moderately dry –2.00 to –1.50 Severe drought –1.99 to –1.50 Severely dry < –2.00 Extreme drought = –2.00 Extremely dry The parameters a and ß should be defined so that they match the precipitation distribution for each time series and station separately. The pro­cess was described in more detail by McKee et al. (1993), who determined the calculation of the pa­rameter estimates by the maximum probability method. The equations are as follows: 1 (1+.1+4........ ......... =) (5) 4........3 ........ ........^ =(6) ......... ........................ ........=........................-.(7) ........ With the obtained parameters . , ., and A, we were able to find the distribution function. Since the gamma distribution is not defined at .=0, the equation is modified and defined as the following: ........(........)=........+(1-........)........(........) (8) . probability with no precipitation (.=0); . = ./. . number of precipitation periods . number of observations The final step is to transform the theoretical distribution into a standardized Gaussian varia­ble with an average of 0 and a standard deviation of 1. For a quicker calculation of SPI, a computer program was used. The program is available on the website of US National Drought Management Centre (2015). Calculation of standardized groundwater index – SGI Standardised Groundwater Index - SGI (Bloomfield & Marchant, 2013; Draksler et al., 2017) represents the number of standard devia­tions of the groundwater level deviating from the long-term average for the selected interval. SGI is based on the same principle as SPI, but there are two major differences. The first is that, for the groundwater level as an input variable, it is unnecessary to separate the parameter into pre­ defined time periods. The second difference is in choosing the correct fit and distribution of raw data, since SGI seldom fits the gamma distribu­ tion, as is typical for SPI (Bloomfield & March-ant, 2013). If the parameter is unevenly distribut­ed, we use non-parametric methods. In this case, each calculated monthly measurement of ground­water level gets a value that is determined on a basis of rank within the entire set of measure­ments. The obtained values are then determined by the inverse normal cumulative distribution. If measurements are already evenly distributed, parametric methods may be used following the procedure described for the SPI calculation. The results are SGI values within the range from +2 to –2 (Table 1). In our case, we selected a Gaussian distribu­tion for transformation, because we get the best fit depending on theoretical distribution. We ran­domly transformed the variable with the follow­ing equation (Bloomfield et al., 2015; Draksler et al., 2017; Chu, 2018): ........-........ ........ = (9) ........ x random variable µ arithmetic mean of data in observed time interval s standard deviation of data in observed time interval Calculation of the probability of a continuous, normally distributed variable was performed us­ing the following equation (Bryc, 1995): 1 ........-(........-........)2 ................ = 2........2 (10) ........v2........ To use the inverse normal cumulative distri­bution function, each value of the probability .. is converted from 1/(2.) to 1 – 1/(2.). The relation between SPI and SGI for ground­water stations were analysed with Pearson’s correlation coefficient (Rodgers & Nicewander, 1988): ........ .........=1 (................-........)(................-........ ) ........ = ................ ..........=1 (................-........)2..........=1 (................-........)2 (11) . average value of observations for . . average value of observations for . n number of observations xi, yi observed values with index i Results Groundwater stations and time intervals After reviewing the calculated monthly groundwater measurements on 22 groundwater stations, the availability and consistency of the data were checked. At some groundwater sta­tions, the data sets are not long enough, they do not coincide with other stations, or they do not fit to the theoretical distribution (possible rea­sons are indicated for each selected time inter­ val separately). Because of that, some stations were omitted (Table 3). Where the set of missing monthly values for individual groundwater sta­tion was shorter than 6 months (station Brunš­vik, Kungota, Zgornje Jablane, Spodnja Hajdi­na), they were replaced by linear interpolation based on the comparison with neighbouring sta­tions. Stations used in the analysis are presented in Table 2 and Figure 4. To compare results of calculations, the time intervals between different stations must over­lap. Based on the data overlapping, four time in­tervals were defined (Table 2). 1. 1956–2000: The period enables to detect older dry periods, but for this period, only two stations are suitable for the analysis. During this period, boundary conditions of Dravsko-Ptujsko polje aquifer has changed, which gave a disad­vantage to the analysis and caused substantial changes in time-dependent trends and ground­water level fluctuations. 2. 1982–2012: Due to a 30-year time range, this is the most suitable interval. Six stations are suitable, which allows general analysis of drought spatial distribution. Unfortunately, in this time interval, no station is available in the west and south part of the observed area. Dur­ing the interval changes in the aquifer, boundary conditions were present. 3. 1991–2011: The advantage of the time inter­val is a relatively large number of 12 groundwater stations, distributed throughout the entire area. Fluctuations of groundwater levels at the stations do not have a distinct trend, which improves the quality of drought analysis. The disadvantage of the interval is a short period that covers only 20 years, which is not entirely appropriate for the analysis of SGI. According to the basic method­ology, the calculation requires at least a 30-year dataset (Bloomfield & Marchant, 2013). 4. 1990–2016: The interval was chosen to an-alyse recent dry periods. The interval is not en­tirely appropriate, as it has a length of 26 years. The number of relevant stations is 12, which is providing reasonable spatial representation. The disadvantages of the period are bigger changes in groundwater levels that happened from 2012 at several observation stations. Table 2. Groundwater stations used in the analysis. Name of the borehole Location GKX [m] GKY [m] Measuring period Selected period 1. 1956–2000 2. 1982–2012 3. 1991–2011 4. 1990–2016 0890 Bohova 151899 550523 1990–2016 X X 1710, Bru-1/11 Brunšvik 144522 555551 1956–2016 X 2401, 2411, 2412, Ku-2/09 Kungota 142561 560725 1990–2016 X X 1250, Rac-1/11 Race 146264 552615 1990–2016 X X 2830, SHaj-2/14 Spodnja Hajdina 141564 564525 1981–2016 X X X 2120, Sta-1/11 Starše 146842 558519 1981–2016 X X X 1631 Zgornja Gorica 142587 553273 1990–2016 X X 1600 Zgornje Jablane 139878 555058 1956–2016 X X X X 0721 Tezno 153620 552320 1969–2016 X X X 0370, Do-2/09 Dornava 143579 573033 1981–2016 X X X 0152 Gorišnica 141084 578251 1990–2016 X X 0283, Sob-1/14 Sobetinci 140792 574746 1990–2016 X X 0060 Trgovišce 141641 584612 1990–2016 X X X Table 3. Groundwater stations that were omitted from the analysis. Name of the borehole Location GKX [m] GKY [m] Measuring period 0290 Damiševo naselje 157858 546607 1979–1989 1030 Dobrovce 148990 554200 1956–2016 3040, Lp-01 Draženci 137248 565618 1981–2016 Rog-1/11 Rogoza 151413 552973 2012–2016 Buk-1/14 Bukovci 137666 574631 2015–2016 0531, 0721 Ptuj 141989 567766 1982–2016 0051, 0230 Cvetkovci 141100 582420 1960–1981 0210, 0211 Mala Vas 138633 578811 1965–1984 0280 Sobetinci 140792 574746 1954–1983 0240 Stojnci 137770 575360 1981–2015 Fig. 4. Dravsko-Ptujsko polje groundwater station locations that were used in analysis (cartographic basis Geodetska uprava Republike Slovenije, DPK750, 2017). Trend analysis Time intervals analysis In most cases, the measurements are contin­uous and distributed as unimodal distributions. For groundwater stations where the data devi­ate from the unimodal distribution, it is typical that they have a large amplitude of fluctuations (e.g. Race and Starše station), or the aquifer re­acts rapidly to the periods of recharge, which results in high deviations from the average val­ues of the groundwater level (e.g. the Sobetinci station). Therefore, models of unimodal distri­butions cannot be approved by the testing with Kolmogorov-Smirnov and Anderson-Darling tests. Such behaviour can be observed on stations Race (Fig. 5a), Spodnja Hajdina (Fig. 5b), Zgornje Jablane, Starše, Trgovišce, and Sobetinci. At such stations, further processing of data was not performed. Even though this is a real condition in the aquifer, it is a result of influences on the aquifer, which cannot be defined without detailed analysis. A significant linear trend in groundwater levels influences time appearance of drought events through time. For further anal­ysis, different time intervals were selected, such that groundwater levels were not deviating from long-term average. In the continuation, each time interval is pre­sented in detail. In the tables (Tables 4–7) are data for individual groundwater station: the range of groundwater level fluctuations, number of drought periods, trend of groundwater lev­el fluctuations, maximum intensity I, maximum deficit D of the dry period defined as lowest 10 % percentile – P10, and minimum and maximum drought duration. The first interval (Table 4) represents mea­surements from year 1956 to year 2000. The Brunšvik station has stronger intensities I of the dry periods than the Zgornje Jablane station, which is probably due to a higher amplitude of groundwater level fluctuation. Same can be said for the size of the deficit D of drought periods, which is greater at the Brunšvik station. We assumed that this is a consequence of a thick­er aquifer, which, in addition to rainfall, is also supplied by Pohorje streams. Since groundwater is located at a depth of 10 to 15 m, it takes longer to experience drought, which in turn means that it is more intense and long-lasting. The Zgornje Jablane station is in the more southwestern part of the Dravsko polje, where the aquifer is lim­ited by the Holocene clay sediments of Pohorje streams. We can still define the fluctuation as large (depending on the range of amplitudes of other groundwater stations in the Dravsko-Ptu­jsko polje), but due to the low groundwater depth (1–5 m), the drought is recovered with short-term precipitation. This is confirmed by the fact that we noticed many shorter dry periods (2–3 months) in this area. Calculation of SGI (Fig. 6) shows that the dry periods in the past did not appear as often as in the period from 1980 to 2000. Severe droughts indicated by a value of –1.5 and less have been occurring almost every year since 1975. The cal­culated SGI that shows periods of severe drought coincide with the drought periods defined by P10. The second interval (Table 5) represents mea­surements from year 1982 to year 2012. We can see that the intensities I of the dry periods of the Dornava, Tezno, and Starše stations are stron­ger. For the Trgovišce and Spodnja Hajdina, the Table 4. Descriptive statistics for the first interval between years 1956 and 2000. Station Max. GW level fluctuation (m) Number of drought periods Trend of GW fluctuation Max. I of dry period (m) Max. D of dry period Duration (day) Min. Max. Brunšvik 5.93 10 decrease 0.69 151 28 275 Zg. Jablane 3.97 17 decrease 0.34 56 31 214 GW – groundwater drought intensity values do not exceed 0.23 m. In all cases, with time we observe an increase in the intensity of dry periods. The exception is the Spodnja Hajdina station. The size of the deficit D of drought periods between the groundwater stations appears quite evenly, and the difference between the deficits in individual stations is no­ticed. Dornava, Tezno, and Starše have a larger deficit. Dornava and Tezno are located on the margins of the field where the deficit depends on the amplitude of the fluctuations of groundwater levels. The recharge is also influenced by nearby streams. At the Starše station, located in the mid­ dle of the Dravsko polje, the size of the deficit and the intensity is a consequence of greater aquifer thickness. SGI was calculated (Fig. 7) at all groundwa­ ter stations except for the Zgornje Jablane, since for the second interval, the empirical distribu­tion has not proper fit to the theoretical Gauss­ian distribution. For other stations, SGI showed three larger periods of severe drought when SGI values were below –1.5. For the first time, such an extreme event occurs in the year 1993 at all stations, except in the Starše station. The second larger period is between 2000 and 2003. The ex­ceptions are the Spodnja Hajdina and Trgovišce stations, where the dry periods are shorter with the rapidly changing SGI. This reflects a thinner unsaturated area at the observed station. The third larger period occurs in December 2011 and persists to the end of 2012. It is a period that is common to all stations where the intensity ris­ es equally. The SGI values at Trgovišce, Dornava and Starše exceed –2.0, which is characterized by extreme drought. All stations in the Dravsko polje have common drought periods since 2000. The most likely rea­son for this is a permanent trend of decreasing groundwater level. Exceptions are Trgovišce and Dornava, where the trend of groundwater level is not detected. Fig. 7. SGI graph of second interval of measurements betwe­en years 1982 and 2012. The third interval (Table 6) represents mea­ surements from year 1991 to year 2011. We no­ticed that between the dry periods, Tezno, Bo-hovo, Starše, and Kungota stations have higher intensities I. These are areas with higher ampli­tudes of groundwater fluctuations, which also affects the size of the drought intensity. Race, Zgornja Gorica, and Trgovišce stations are char­acterized by a small amplitude that is reflected in the lower intensity of dry periods. The size of the deficit D increases with time at most ground­water stations. Table 5. Descriptive statistics for the second interval between years 1982 and 2012. Station Max. GW level fluctuation (m) Number of drought periods Trend of GW fluctuation Max. I of dry period (m) Max. D of dry period Duration (day) Min. Max. Sp. Hajdina 1.47 10 decrease 0.16 39 31 334 Starše 2.26 5 decrease 0.39 81 30 365 Tezno 3.62 7 decrease 0.34 83 31 334 Dornava 2.16 16 decrease 0.53 98 31 245 Trgovišce 1.04 15 decrease 0.23 26 28 183 GW – groundwater Table 6. Descriptive statistics for the third interval between years 1991 and 2011. Station Max. GW level fluctuation (m) Number of drought periods Trend of GW fluctuation Max. I of dry period (m) Max. D of dry period Duration (day) Min. Max. Bohova 5.44 5 not present 0.74 135 61 273 Kungota 3.13 2 not present 0.48 336 61 702 Race 0.69 6 not present 0.16 38 61 355 Sp. Hajdina 1.28 6 decrease 0.15 34 61 304 Starše 1.97 4 decrease 0.34 104 59 334 Zg. Gorica 1.24 12 not present 0.16 31 28 304 Zg. Jablane 1.90 9 decrease 0.15 18 31 153 Tezno 2.55 4 decrease 0.33 61 61 334 Dornava 2.07 8 not present 0.23 41 61 184 Gorišnica 1.69 8 decrease 0.23 28 31 184 Trgovišce 0.95 8 not present 0.15 23 30 153 GW – groundwater Table 7. Descriptive statistics for the fourth interval between years 1990 and 2016. Station Max. GW level fluctuation (m) Number of dro­ught periods Trend of GW fluctuation Max. I of dry period (m) Max. D of dry period Duration (day) Min. Max. Bohova 5.44 6 not present 0.70 128 61 304 Kungota 4.17 3 increase 0.63 479 31 758 Zg. Gorica 1.24 21 not present 0.22 47 28 304 Tezno 2.55 5 decrease 0.32 87 61 334 Dornava 2.80 9 not present 0.34 124 30 365 Gorišnica 2.28 7 not present 0.22 88 61 396 The calculation of SGI (Fig. 8) for the third interval of measurements was possible at all stations except for Sobetinci, because it has an asymmetric distribution of data; therefore, fitting it to Gaussian distribution was not possible. Oth­erwise, SGI shows two major periods with severe drought, meaning that SGI is lower than –1.5. First, it occurs at the end of year 1993 and lasts until spring 1994. Exceptions are the Starše and Kungota stations where drought occurs, but they were less intensive. The second period occurs be­tween years 2001 and 2004. It starts at the end of summer 2001, but the aquifer does not recover due to lack of precipitation until spring 2003. At that time, there was a decrease in intensity at all loca­tions, but it then starts rising until January 2004. This period is particularly persistent around Starše and Kungota stations. SGI between 2003 and 2004 at all stations exceeds –2.0, indicating extreme drought (Table 1). At Kungota station, this value persisted for two years. The smallest fluctuations, between years 2001 and 2004, occurs in stations Zgornja Gorica, Race, Trgovišce, and Gorišnica. This is due to the small thickness of the unsaturated area and con­sequentially the fast response to the recharge. The fourth interval (Table 7) represents mea­surements from year 1990 to year 2016. The high­est drought intensity I is noticeable at the Kun­ gota, Bohova, Tezno, and Dornava stations. As mentioned before, this is due to the higher am­ plitude of the groundwater level fluctuation. The highest drought intensity was recorded at the Kungota station with 0.64 m. The low drought in­tensity is typical for the Zgornja Gorica station where intensity does not exceed 0.20 m. There is also a positive linear trend in the increasing in­tensity of dry periods. The same applies to the size of the deficit D of dry periods P10. In this period, empirical distributions of many stations are highly asymmetric and con­sequently do not fit to Gaussian distribution. We have applied transformation to transfer these distributions closer to theoretical, but again Kolmogorov-Smirnov and Anderson-Darling tests were not significant. These data were not analysed. Three periods are typical for SGI smaller than –1.5 (Fig. 9). The first is the year 1993, visible at all stations. The smallest deficit of dry period is present at the Kungota station. The second is the period between 2000 and 2004. There is a slight increase in the groundwater level in 2001 and 2003 throughout all locations, alleviating the in­tensity of the dry season. The exception again is the Kungota station, this time due to SGI with less than –2.0. Where groundwater is shallow, the curve is very irregular indicating a rapid re­sponse of the aquifer to the recharge. The third period started in summer 2011 and persisted un­ til autumn 2013. The deficit is visible throughout all groundwater stations. The most variable in the period is index at the Zgornja Gorica station. Fig. 9. SGI graph of fourth interval of measurements betwe­en years 1990 and 2016. Comparison of meteorological drought with groundwater drought Depending on the meteorological drought, the groundwater drought occurs with a lag, the length of which depends on the thickness of the unsaturated zone, porosity and transmissivity. Since hydrogeological systems differ one from another, the influence of the coincidence of these types of drought varies. We have chosen six dif­ferent time scales for calculating SPI: SPI1, SPI2, SPI3, SPI6, SPI9 and SPI12. To compare meteorological and groundwater drought, SPI was calculated for three meteoro­logical stations positioned on the Dravsko-Ptujs­ko polje: precipitation stations Tezno, Starše and Zgornje Jablane. The time interval between year 1982 and year 2012 was chosen, despite the de­creasing groundwater level trend. The results are shown in the figure (Fig. 10). On shorter time scales, the SPI variability is greater than on longer time scales. The reason is representation of seasonal, short-term droughts. Based on the SPI and SGI graphs, we concluded that the Zgornje Jablane station does not show any delay in terms of the meteorological drought (Fig. 10c). Both droughts appear simultaneous­ly, which is particularly noticeable in years 2002 and 2012. SPI12 for year 2002 is –1.54 in January, while in the same month the SGI value is –1.35. 1982–2012, b) precipitation station Starše and groundwater station Starše from 1982–2012 and c) between precipitation station Fram and groundwater station Zgornje Jablane from 1982–2012. At the Tezno station, there is a delay in the ap­pearance of groundwater drought (Fig. 10a). These differences are most noticeable in years 1993 and 2012, when groundwater drought occurs with an average half-year lag. For the year 2012, SPI12 has the lowest value in January when it exceeds –3.0, while SGI is the lowest in May with a value of –1.63. The situation is similar for the year 1993. The meteorological drought at the precipita­tion station Starše (Fig. 10b) does not coincide with the groundwater drought observed at the groundwater station Starše. The shift between the lowest SPI and SGI value is greater than near Tezno. In August 2000 when the SPI12 reached the lowest value of –2.77 and when later negative values persist until the next summer, negative SGIs have started slowly but have been steadily decreasing since the end of 2000 until they reach the lowest value of –1.72 in August 2002. The amount of precipitation then increased, which led to an increase of both indices; the trend reverses again when the SPI12 persists with the negative values throughout 2003. SGI reaches the lowest value of –2.19 only in March 2004. A delayed re­sponse of groundwater to recharge is apparent. Drought periods occurrence map Despite the short range of measurements, we showed the third interval of measurements (1991–2011), where the density of the stations on the western and southern parts of the Dravs­ko-Ptujsko polje are more dense (Fig. 11). The period from July 2002 to April 2003 is character­ized by extreme drought. We can observe that the SGI values vary by month and location. For July 2002 (Fig. 11a), drought periods with an index of –1.5 and more are present. The drought was spread over the entire Dravsko-Ptujsko pol-je. The lowest SGI value is in the north-west­ern part of the area, while in the western part (near Zgornje Jablane) the values were not lower than –1.0. The reason for this is a recharge from the Pohorje streams on the western part of the area. In October 2002 (Fig. 11b), the SGI values decreased in the central part of the area (still above –1.6), and then values are diminishing to­wards the east. And the dry period significantly diminishes around Zgornje Jablane and Trgov­išce. In January 2003 (Fig. 11c), the groundwater deficit is only present in the central part of the area (near Kungota). In the east and northwest, SGI rises above 0.0, indicating a period without groundwater drought. In April 2003 (Fig. 11d), the dry period in the central part of the area is still present. The SGI around Kungota is around –1.6, which shows a severe drought. There is no drought in the north-west of the area. Again, the reason is in the aquifer recharge from the Pohor­ je streams. There is a deficit to the east, where SGI is between 0.0 and –0.7. Discussion The presented analysis of groundwater drought can be divided into three parts. The first part consisting on the ranking statistics of groundwater fluctuations and the second part on the calculation of Standardized Groundwater In­dex – SGI. The third part represents a compari­son between Standardized Precipitation Index – SPI and Standardized Gorunwater Index – SGI. In the area of Dravsko-Ptujsko polje, based on the ranking statistics, we have identified one-to three-month periods of groundwater deficit, which most often occur in autumn or winter. We conclude that this is a consequence of the delayed impact of the meteorological drought that occurs in the summer. When short-term summer drought periods occur, they often have greater intensity than short-term winter drought periods. and d) April 2003. In the western part of the Dravsko-Ptujsko polje, the amplitude of groundwater level fluctu­ations is up to 5 m high (Brunšvik station), while in the eastern part it does not exceed 1 m (Trgov­išce station). This has also effects on the duration and intensity of dry periods. In the north-west­ern part, the Brunšvik and Tezno stations have the longest and most intense dry periods. In the southeast, the Sobetinci, Gorišnica, and Trgov­išce stations have several shorter dry periods, characterized by a low intensity that does not in­crease with the length of the event. Many one- to three-month dry periods occur in the south-east­ern part of the field in summer, as a response to the meteorological drought is almost immediate. The reason is the small thickness of the unsatu­rated zone. Groundwater is at the depth of 5 m; therefore, the rare longer periods of drought are not the result of the delayed impact of the aquifer but the persistence of meteorological droughts. During the analysis of different time intervals, we indicated a decreasing trend of groundwater level, which affects the variety of drought intensi­ty and size of deficit. Due to the decreasing trend in recent time, many dry periods have occurred. Dry periods do not occur evenly but depend on local changes in the aquifer. Sometimes, we detect very monotonous drought periods, some­times drought periods are locally distributed. Therefore, the analysis of groundwater deficits should consider local hydrogeological and geo­logical characteristics of individual aquifers. This is confirmed by the fact that uniform defi­nitions of groundwater drought cannot be given. Each region under consideration has a different variation of the variables. Based on the SGI calculations, the worst long-lasting droughts usually begin in winter, when the aquifer does not recover after the pre­vious summer drought. Since the amount of re­charge is insufficient in the springtime, along with the onset of the next summer, the intensity of drought increases and causes an even greater shortage of groundwater. An example of severe droughts in years 2003 and 2012 is seen at all sta­tions on the Dravsko-Ptujsko polje. A visual comparison between SGI and percen­tile P10 calculations found that the drought pe­riods determined by both methods coincide. The comparison of the dry period’s size is character­istic between the value of P10 and the SGI cat­egory, which indicates the occurrence of severe drought with values less than or equal to –1.5. This confirms the suitability of both methods for analysing groundwater drought. From the comparison of SGI and SPI, we have discovered that locations with a higher ground­water level amplitude, where the duration and intensity of drought periods are higher, also have a greater lag in terms of the occurrence of mete­orological droughts. At the Tezno station, the lag for the period from 2002 to 2003 is six months. Stations with a smaller amplitude that are typ­ical for the eastern part of the Dravsko-Ptujsko polje reflect the shallow groundwater level. It also follows that relation between groundwater drought and meteorological drought is influ­enced by the thickness of vadose zone. Where the unsaturated zone is thicker, it takes longer time for meteorological drought to reach groundwater (e.g. Tezno and Starše). If it occurs, the intensity of the dry season is stronger, which means that it takes longer time for the aquifer to recover. Conclusions Groundwater drought is a phenomenon that must be investigated in more details in the fu­ture. Several theoretical improvements are need­ ed in the future; among them is the redefinition of groundwater drought, which cannot be solely based on the groundwater level fluctuation anal­ysis, but it must include also amount of water stored in the aquifer. Our analyses have shown that for Dravsko-Ptujsko polje, methods for groundwater drought analyses can be applied as they are already presented in the current sci­entific literature. Drawbacks of the methods ap­plied are only indirectly indicated. At present, the conclusions of the case study are as follows: -Groundwater drought develops slowly in time and space. -The occurrence of groundwater drought depends on the thickness of the unsaturat­ed and saturated aquifer zone. -Where the depth to groundwater level is greater, droughts occur with a longer delay and greater intensity and where the thick­ness of unsaturated zone is small, the re­sponse to meteorological influences is fast­er. -Standardized Groundwater Index – SGI is a more suitable index than percentile val­ues of groundwater level; it integrates more information about groundwater fluctua­tions than percentile values. As other types of drought, also groundwater drought is a complex event. From that point of view, it is important to consider different types of indices. We have illustrated applicability com­parison of meteorological drought indices with groundwater drought indices. Beside the appli­cation of indices, it is also important to consider aquifer’s dynamics. One of the drawbacks of our analysis is the lack of longer groundwater level time series and spurious spatial distribution of stations. At present, the spatial distribution of groundwater monitoring stations in Dravsko-Ptujsko polje has improved, and it is recommended to repeat our calculations in due time. It is also important to focus more on the aquifer boundary condi­tions that have changed several time during the course of time on Dravsko-Ptujsko polje. Also, some statistical theoretical questions in relation to groundwater level data treatment remains to be opened among them are important questions connected to the fitting of theoretical distribu­tions in relation to extreme values. Acknowledgement The authors acknowledge the financial support from the Slovenian Research Agency in the frame of research program »Groundwater and Geochemistry« (No. P1-0020), which is carried out by the Geological Survey of Slovenia. 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CC Atribution 4.0 License https://doi.org/10.5474/geologija.2019.013 Ocena doseganja trajnostnih ciljev z vidika upravljanja in varovanja podzemnih voda v Sloveniji Assessment of achieving sustainable goals from the groundwater management and protection perspective in Slovenia Jože UHAN & Mišo ANDJELOV Agencija Republike Slovenije za okolje,Vojkova 1b, SI-1000 Ljubljana, Slovenija e-mail: joze.uhan@gov.si Prejeto / Received 18. 11. 2019; Sprejeto / Accepted 12. 12. 2019; Objavljeno na spletu / Published online 24. 12. 2019 Kljucne besede: podzemna voda, trajnostno upravljanje, vodni odtis, kolicinski stres, nitrat Key words: groundwater, sustainable management, water footprint, quantitative stress, nitrate Izvlecek Doseganje trajnostnih ciljev upravljanja in varovanja podzemnih vodnih virov v plitvih vodonosnikih Slovenije smo ocenili preko kazalnikov stresa za kolicinsko in kemijsko najbolj obremenjene aluvialne vodonosnike vodnih teles podzemne vode: Savska kotlina in Ljubljansko Barje, Savinjska kotlina, Krška kotlina, Dravska kotlina in Murska kotlina. S tem smo poglobili dosedanji pristop ocenjevanja stanja podzemne vode v Sloveniji, kot ga za obmocje posameznih vodnih telesih doloca Okvirna direktiva o vodah. Stopnja izkorišcenosti podzemnih voda je na posameznih najbolj obremenjenih delih plitvih vodnih teles izrazito vecja, kot je bila do sedaj ocenjena na celotnih vodnih telesih. V nekaterih primerih, kot je vodonosnik Ljubljanskega polja, se kolicina crpanja pri srednih nizkovodnih razmerah že približuje polovici vseh razpoložljivih podzemnih vodnih virov. Stopnja nitratnega onesnaženja podzemne vode pa je na nekaterih aluvialnih vodonosnikih vodnih telesih, kot so Krška, Dravska in Murska kotlina, v manj vodnatih letih že presegla mejo trajnostne rabe podzemnih vodnih virov. Abstract Achieving the sustainable goals for management and protection of groundwater resources in shallow aquifers in Slovenia was evaluated with stress indicators for the alluvial aquifers of groundwater bodies with the highest quantitative and qualitative pressures: Savska kotlina with Ljubljansko Barje, Savinjska kotlina, Krška kotlina, Dravska kotlina and Murska kotlina. We have deepened the approach taken so far to assess the status of groundwater in Slovenia as defined by the Water Framework Directive for the area of individual bodies of water. The level of groundwater exploitation is markedly higher in some of the most polluted parts of shallow groundwater bodies than has been estimated so far in whole groundwater bodies. In some cases, such as Ljubljansko polje aquifer, the groundwater withdrawals in mid-low-water conditions are already approaching half of all available groundwater resources. In some alluvial aquifers of groundwater bodies, such as Krška, Dravska and Murska kotlina, the level of groundwater nitrate pollution in dry years has already exceeded the limit for the sustainable protection of groundwater resources. Uvod lopment Goals) v Sloveniji (Sachs et al., 2019) Med pomembnimi splošnimi cilji trajnostne-izpostavlja nekaj pomembnih izzivov tudi na ga razvoja, ki so jih Združeni narodi zapisali v podrocju zagotavljanja ciste vode in sanitarne agendi za trajnostni razvoj 2030, je tudi dostop ureditve (SDG6) ter odgovorne porabe in pro-do vode in trajnostno upravljanje z vodnimi viri, izvodnje (SDG12). Dosedanje regionalne ocene da bomo lahko zadovoljili potrebe današnje in kolicinskega stanja podzemnih voda v Sloveni­prihodnjih generacij (United Nations, 2015). ji sicer ne nakazujejo neugodnega razmerja med Trajnostno upravljanje voda bo tudi po mnenju razpoložljivimi in crpanimi kolicinami podze-Evropske komisije pomembno vplivalo na zmo-mne vode, po posameznih plitvih vodnih telesih žnost cloveštva, da se prilagodi spreminjajocim z medzrnsko poroznostjo pa crpane kolicine že se okoljskim, družbenim in ekonomskim raz-presegajo 20 % obdobno razpoložljivih kolicin meram. Pregled napredka pri doseganju ciljev podzemne vode (Andjelov et al., 2016). Poleg ome­trajnostnega razvoja (SDG - Sustainable Deve-njenega pa so kar tri vodna telesa podzemne vode ocenjena s slabim kemijskim stanjem in vec kot polovica oskrbovalnih obmocij pitne vode ima v Sloveniji stalno potrebo po dezinfekciji vode (So­ vic, 2017). Zaradi tega vse bolj izstopa potreba po metodološki razširitvi dosedanjega ocenjevanja stanja voda in po nadaljnjih preverbah dosega­nja trajnostnih ciljev na podrocju crpanja in one-snaževanja podzemnih vodnih virov. Hipotezo o ucinkovitosti uporabe konceptov vodnega odtisa (Hoekstra & Hung, 2002; Hoekstra, 2003; Gleeson & Wada, 2013; Esnault et al., 2014; McDonald et al., 2014) ter odtisa sive podzemne vode (Hoekster et al., 2011; Franke et al., 2013) pri razširitvi do-sedanjega ocenjevanja stanja voda in trajnostne­ga upravljanja podzemnih voda v Sloveniji smo poskušali preveriti na najbolj obremenjenih in hkrati najbolj ranljivih vodnih telesih podzemne vode v Sloveniji. Podatki in metode Študijsko obmocje Za ocenjevanje doseganja trajnostnih ciljev z vidika upravljanja in varovanja voda v Sloveniji smo za študijsko obmocje izbrali pet aluvialnih vodonosnikov vodnih teles podzemne vode (sl. 1), odprtih vodonosnikov z medzrnsko poroznostjo in s povprecno gladino podzemne vode od nekaj metrov do najvec 25 metrov pod površjem. Za podrobnejšo preverbo doseganja trajno­stnih ciljev na podrocju crpanja in onesnaževa­nja podzemnih vodnih virov smo izbrali dva alu­ vialna vodonosnika z veliko kolicinsko in veliko kemijsko obremenitvijo: -Ljubljansko polje (69,4 km2) s povprecno 2,1 m3/s crpane podzemne vode, kar pred­stavlja okoli 6,7 % povprecno nacrpane podzemne vode v Sloveniji in -Spodnjo Savinjsko dolino (76,7 km2) s pov­precnim vnosom 42,3 kg dušika na hek-tar kmetijske obdelovalne površine v letu 2014, kar za 39 % presega povprecno obre­menitev z dušikom na vseh kmetijskih ob-delovalnih površinah v Sloveniji. Vodno telo podzemne vode VTPodV_1001 Sa­vska kotlina in Ljubljansko Barje, kamor se uvr-šca vodonosnik Ljubljanskega polja, s 21,1 % crpane razpoložljive kolicine podzemne vode v Sloveniji predstavlja povecano tveganje za do-seganje dobrega kolicinskega stanja, predvsem zaradi velikega crpanja podzemne vode iz Lju- Sl. 1. Študijska obmocja aluvialnih vodonosnikov vodnih teles podzemne vode v Sloveniji. Fig. 1. Study areas of alluvial aquifers of groundwater bodies in Slovenia. bljanskega polja (MOP, 2016). Vodno telo podze­mne vode VTPodV_1002 Savinjska kotlina je z aluvialnim vodonosnikom Spodnja Savinjska do- lina že od prvega nacrta upravljanja voda (MOP, 2009) v slabem kemijskem stanju, predvsem zara­ di preseženih vsebnosti nitrata v podzemni vodi. Koncept ocenjevanja kolicinskega stanja in kolicinskega odtisa podzemne vode S konceptom ocenjevanja kolicinskega stanja podzemnih voda je okvirna vodna direktiva (Di-rektiva 2000/60/ES) uvedla zakonodajno obvezo po poznavanju razpoložljivih kolicin vode v po­sameznih vodnih telesih podzemnih voda za vse države clanice. Primerjanje crpanih in razpo­ložljivih kolicin podzemne vode je s tem postal osnovni kazalnik kolicinskega pritiska na pod-zemne vodne vire in kazalnik vodnega stresa v razlicnih ocenjevalnih shemah (Vrba & Lippo­nen, 2007). Ocena razpoložljivih kolicin podzemnih voda izhaja iz poznavanja letnega kolicinskega obnav­ljanja podzemne vode ter ocene potrebnih koli-cin podzemnih voda za ohranjanje ekosistemov in doseganje dobrega ekološkega stanja povr­šinskih voda. Letno kolicino obnavljanja podze­mne vode v Sloveniji ocenjujemo z regionalnim vodnobilancnim modelom GROWA-SI (Andjelov et al., 2016), ki se na obmocjih kolicinsko mocno obremenjenih vodonosnikov z medzrnsko poroz­nostjo za podporo upravljanja voda dopolnjuje z rezultati šestih lokalnih modelov toka podzemne vode, ki so bili izdelani s programskim orodjem MODFLOW (Souvent et al., 2016). Letne kolicine podzemnih voda za ohranja­nje ekosistemov in doseganje dobrega ekološkega stanja površinskih voda so bile po posameznih vodnih telesih podzemnih voda celotnega ob-mocja Slovenije podana po metodologiji Janže in sodelavcev (2016), ki loceno obravnava potrebne kolicine podzemnih voda za ohranjanje: -gozdnih habitatov na aluvialnih vodonos­nikih ob pomoci locevanja modelirane re-alne evapotranspiracije v izhlapele pre­ strežene padavine, prepušcene padavine, ki izhlapevajo iz tal, in izhlapevanje preko rastlin, -habitatov dvoživk ter mehkužcev na kraških obmocjih ob uporabi locevalnih možnosti modela z obravnavo podzemnega odtoka kot vsote modeliranega podzemne­ ga in pripovršinskega odtoka ter -dobrega ekološkega stanja površinskih voda ob uporabi nemškega vodnobilancne­ ga pristopa s scenarijem petih sušnih let v zadnjem tridesetletnem obdobju (Schlter, 2006), kar je približek vrednosti dvajsete­ga centila kolicine napajanja vodonosnikov v referencnem vodnobilancnem obdobju in predpostavlja mejo slabih habitatnih recnih pogojev, pogosto umešceno v razpon od 10 do 30 % povprecnega letnega pretoka Qs (Tennant, 1976). Omenjena regionalna ocena letnih potrebnih kolicin podzemnih voda za ohranjanje ekosis­temov in doseganje dobrega ekološkega stanja površinskih voda je zelo posplošena. V prime-ru kolicinsko najbolj obremenjenih vodnih teles podzemne vode je priporocljiva ocena prispevka podzemne vode k ekološkemu pretoku reke (E) tudi preko razmerja med baznim (Q) in ce­ bazni lotnim naravnim pretokom (Q). Ob tem pa je celotni potrebno upoštevati ekološko sprejemljiv pretok (Qes) (Charchousi et al., 2018). Q bazni E =· Q Qes Q celotni Prispevek podzemne vode k ekološkemu pre­toku (E) je torej mogoce oceniti ob poznavanju celotnega in baznega pretoka oz. ob poznavanju njunega razmerja, ki ga predstavlja indeks ba­znega odtoka (BFI). Za oceno baznega odtoka smo pri modeliranju vodne bilance Slovenije za ob-dobje 1981–2010 (Andjelov et al., 2016) uporabili metodologijo izracunov, znano pod oznako MoM-LRr (Wundt, 1958; Kille, 1970; Demuth, 1993). Bazni odtok je po tej metodi vrednost mediane nizkih dnevnih pretokov v n mesecih obravnava­nega tridesetletnega obdobja 1971–2000 na pre­mici najboljšega prileganja, kjer enacba premice z zacetno vrednostjo (y0) in smernim koeficien-tom (m) izhaja iz postopne regresijske analize li­nearnega dela porazdelitvene S-krivulje: n MoMLRr = m ·+ y 20 Metodologijo izracuna vrednosti ekološko sprejemljivega pretoka (Qes) v Sloveniji doloca uredba o kriterijih za dolocitev ter nacinu spre­mljanja in porocanja ekološko sprejemljivega pretoka (Uradni list RS, 2009): Qes = f · sQnp Po omenjeni uredbi je ekološko sprejemljiv pretok odvisen od povprecja najmanjših srednjih dnevnih pretokov posameznih let obravnava­nega obdobja (sQnp) in faktorja (f), ki zavisi od vrste odvzema vode, dolžine odseka vodotoka s povratno rabo vode, kolicine odvzete vode, raz­ merja med srednjim in malim pretokom, ekolo­škega tipa vodotoka in od velikosti prispevnega obmocja. Prispevek podzemne vode k ekološko spre­jemljivemu pretoku se izkazuje kot zelo obcutljiv parameter ocenjevanja kolicinskega stanja oz. trajnostne rabe podzemnih vodnih virov in ga je priporocljivo obravnavati po razlicnih pristopih, rezultate pa primerjati preko ocenjevalne sheme kolicinskega odtisa rabe podzemne vode (Gleeson et al., 2012). Kolicinski odtis rabe podzemne vode, ki teme­lji na konceptu vodnega odtisa (Hoekstra & Hung, 2002), vkljucuje tudi princip naravnega obnav­ljanja in pokrivanja potreb ekoloških pretokov. Leta 2012 so pristop prvic uporabili na globalni ravni za oceno velikih regionalnih vodonosnikov, pomembnih za kmetijstvo. V naslednjih letih je ta koncept ocenjevanja prešel v široko uporabo in se izkazal za zelo primeren koncept ocenjevanja trenutne in predvidene rabe podzemne vode tudi na manjših vodonosnikih (Gleeson & Wada, 2013; Esnault et al., 2014; McDonald et al., 2014). V izracunu kolicinskega odtisa rabe podze­mne vode (GF) se crpane kolicine podzemne vode (C) primerjajo s kolicino letnega napajanja (R), zmanjšane za prispevek podzemne vode k eko­loškemu pretoku (E). Ob upoštevanju površine obravnavanega vodonosnika (A) z izracunom kolicinskega odtisa rabe podzemne vode lahko kvantificiramo vodni stres in nakažemo velikost obmocja vodonosnika, ki je potreben za trajno­stno rabo podzemnih vodnih virov: . C . GF = A · GF .. R - E .. Koncept ocenjevanja kemijskega stanja podzemne vode in odtisa sive podzemne vode Ocena kemijskega stanja podzemnih voda v prvem koraku temelji na primerjavi povprecne letne vrednosti državnega monitoringa s stan­dardom kakovosti oz. vrednostjo praga. V pri­meru preseganja mejnih vrednosti so predvideni razlicni preizkusi vpliva onesnaženja, oprede­ljeni z okoljskimi kriteriji in kriteriji rabe pod-zemne vode. Preizkusi se zakljucijo s t.i. splošno oceno kemijskega stanja (European Communiti­es, 2009), ki naj bi podala razmerje med delom vodnega telesa, kateremu pripadajo merilna mes-ta s preseženimi mejnimi vrednostmi ter celot­nim telesom podzemne vode. Principom preizku­sa splošne ocene kemijskega stanja sledi koncept odtisa sive vode (ang. grey water footprint), ki je indikator stopnje onesnaženosti vode in je opre­deljen kot prostornina vode, potrebne za razred- cenje bremena onesnaženja ob upoštevanju vrednosti naravnega ozadja in mejnih vrednosti (Hoekstra et al., 2011). Ob tem se pri razpršenih virih onesnaženja podzemne vode, kot je npr. nitrat, predpostavlja, da le del bremena s pronicujoco vodo doseže vod-no telo. Odtis sive podzemne vode (GWF) je tako razmerje med deležem bremena onesnaženja (L), ki lahko doseže vodno telo, ter razliko med mejno vsebnostjo onesnaževala (C max) in mejno vrednost med naravnim ozadjem in povišanimi vrednostmi nitrata (Cnat): L GWF = c - max cnat Z upoštevanjem kolicine vode, ki doseže za-siceno obmocje vodonosnika (Rinf), lahko preko odtisa sive podzemne vode (GWF) ocenimo stop-njo onesnaženja podzemne vode WPL (ang. water pollution level): GWF WPL = Rinf Za oceno povprecnega letnega napajanja smo na študijskem obmocju vodonosnika Spodnje Sa­vinjske doline uporabili vodnobilancno simula­cijo obdobja 1981–2010 z regionalnim modelom GROWA-SI (Andjelov et al., 2016). Za oceno dele­ža bremena iz bilance dušika obdobja 2007–2014 (Sušin & Verbic, 2019), ki lahko doseže vodno telo podzemne vode, je bil uporabljen regionalni mo­del toka nitrata DENUZ-WEKU (Andjelov et al., 2014; Matoz et al., 2016). Mejno vsebnost onesna­ženja podzemne vode z nitratom smo s 50 mg/l prevzeli po standardu kakovosti za oceno kemij­skega stanja po uredbi o stanju podzemnih voda (Uradni list RS, 2009). Za mejno vrednost med naravnim ozadjem in povišanimi vrednostmi ni­trata, ki so lahko posledica clovekove dejavnosti (Panno et al., 2006), smo za izracun regionalnega odtisa sive vode prevzeli vrednost srednje tocke prevoja na verjetnostnem diagramu porazdelitve modelskih vrednosti nitrata v podzemni vodi vseh rasterskih celic na aluvialnih vodonosnikih po posameznih vodnih telesih (10 mg/l). Ta vred­nost je pricakovano višja od povprecja naravnega ozadja vsebnosti nitrata (3,8 mg/l) v podzemnih vodah izvirov, vodnjakov in vrtin na celotnem obmocju Slovenije (Mezga, 2014) in je blizu vred­nosti srednje tocke prevoja verjetnostne poraz­delitve (8,3 mg/l) vseh rezultatov obsežnih te­renskih meritev vsebnosti nitrata v aluvialnem vodonosniku Spodnje Savinjske doline (Uhan, 2011). Rezultati Shema kazalnikov trajnostne rabe podzemne vode (Vrba & Lipponen, 2007) vsebinsko poe­noteno razširja pogled na dolgorocno vzdržnost rabe podzemnih vodnih virov od obravnave ko­licinskega in kemijskega stanja podzemne vode, kot ga metodološko opredeljuje evropska okvirna vodna direktiva, tudi na podrocje ranljivosti z vidika crpanja in onesnaževanja podzemne vode. Za obmocje Slovenije je ocenjeno sedem kazal­nikov (Tabela 1), ki nudijo prvi splošni pogled na trajnostno rabo podzemne vode na nacionalni ravni. Letna kolicina obnovljive podzemne vode z 2.858 m3, oz. okoli 2.200 m3 razpoložljive pod-zemne vode na prebivalca v Sloveniji, izracuna­na za obdobje 1981-2010, mocno presega splošno prepoznano mejo 1.600 m3, pod katero lahko nas­topi vodni stres in pomanjkanje vode (Turton, 2003). V ocenjevalni shemi (Tabela 1) v Sloveniji izstopata predvsem dva kazalnika, ki govorita o: - razmeroma majhnem deležu crpanih kolicin glede na razpoložljivo podzemno vodo (3,1 %) ob hkrati prevladujocem deležu podzemne vode v oskrbi prebivalstva s pitno vodo (99 %) ter - razmeroma majhnem deležu obmocja Slove­nije s slabim kemijskim stanjem podzemne vode (5,6 %) ob hkrati velikem deležu obmocja povi­šane ranljivosti na onesnaženje podzemne vode (70 %) in posledicno velikim deležem oskrboval­nih obmocij pitne vode s stalno potrebo po prip­ravi vode (60 %). Kazalniki kolicinskega stresa rabe podzemne vode Zaradi velike prostorske in casovne spremen­ljivosti kolicinskega obnavljanja podzemne vode, ocenjenega z regionalnim vodno-bilancnim mo-delom, smo pogled na trajnostno upravljanje pod-zemnih voda na najbolj obremenjenih vodonos­nikih razširili s shemo kolicinskega odtisa rabe podzemne vode glede na modelirane kolicine iz modelov toka podzemne vode in ob tem preverili razlicne pristope k ocenjevanju kolicine podze­mne vode za zagotavljanje potrebnega ekološkega pretoka. Na hidrometricnem prispevnem obmocju, vo­dozbirnem zaledju vodomerne postaje, kolicinsko najbolj obremenjenega aluvialnega vodonosnika vodnega telesa podzemne vode VTPodV_1001 Ljubljanska kotlina in Ljubljansko Barje je preko indeksa baznega odtoka (Charchousi et al., 2018) možno razmeroma zanesljivo oceniti prispevek podzemne vode k ekološkemu pretoku. Po meto­dologiji Wundta (1958), Killeja (1970) in Demutha (1993) je bazni odtok mesecna vrednost media-ne nizkih dnevnih pretokov na premici najbolj­šega prileganja, kjer enacba premice z zacetno vrednostjo (y0) in smernim koeficientom (m) iz­haja iz postopne regresijske analize linearnega dela porazdelitvene S-krivulje. Vrednosti tako dolocenega indeksa baznega toka (Q/Q) baznicelotni vodomernih postaj državnega hidrološkega mo-nitoringa na reki Savi, 3530 Medno in 3570 Šen­ Tabela 1. Trajnostno upravljanje podzemne vode v Sloveniji po prirejeni shemi kazalnikov UNESCO / IAEA / IHP (prirejeno po Vrba & Lipponen, 2007). Table 1. Groundwater sustainable management in Slovenia according to the adapted indicator scheme UNESCO / IAEA / IHP (adapted after Vrba & Lipponen, 2007). KAZALNIKI TRAJNOSTNEGA UPRAVLJANJA PODZEMNE VODE V SLOVENIJI / INDICATORS OF GROUNDWATER SUSTAINABLE MANAGEMENT IN SLOVENIA VREDNOST / VALUE K 1 Letna kolicina obnovljive podzemne vode na prebivalca (MOP, 2016) / Annual quantity of renewable groundwater per capita (MOP, 2016) 2.858 m3 K 2 Crpane kolicine podzemne vode kot delež povprecne letne obnovljive podzemne vode (MOP, 2016) / Groundwater abstraction quantities as a percentage of average annual renewable groundwater (MOP, 2016) 2,3 % K 3 Crpane kolicine podzemne vode kot delež povprecne letne razpoložljive podzemne vode (MOP, 2016) / Groundwater abstraction quantities as a percentage of average annual available groundwater (MOP, 2016) 3,1 % K 4 Podzemna voda kot delež skupne porabe pitne vode (SURS, 2017) / Groundwater as a percentage of total use of drinking water (SURS, 2017) 99 % K 5 Delež obmocja z izcrpavanjem podzemne vode / Percentage of the area with groundwater depletion ni ocenjeno / not evaluated K 6 Crpane kolicine neobnovljivih podzemnih vodnih virov kot delež skupne izkoristljive neobnovljive koli-cine podzemnih vodnih virov / Abstraction of non-renewable groundwater resources as a percentage of total exploitable non-renewable groundwater resources ni ocenjeno / not evaluated K 7 Delež obmocja povišane ranljivosti na onesnaženje podzemne vode (GeoZS, 2016) / Percentage of the area with very high vulnerability to groundwater pollution (GeoZS, 2016) 70 % K 8 Delež obmocja s slabim kemijskim stanjem podzemne vode (MOP, 2016) / Percentage of the area with low groundwater chemical status (MOP, 2016) 5,6 % K 9 Delež oskrbovalnih obmocij pitne vode s stalno potrebo po dezinfekciji vode (Sovic, 2017) / Percentage of the drinking water supply areas with permanent water disinfection need (Sovic, 2017) 60 % K 10 Odvisnost kmetijskega prebivalstva od podzemne vode / Dependence of agricultural population on groundwater ni ocenjeno / not evaluated tjakob (sl. 1), sta 0,47 in 0,54, kar sovpada z re- zultati izracunov povprecnih indeksov baznega odtoka s standardnim programom za racunanje BFI (Srebovt, 2014). Po pristopu Charchousija in sodelavcev (2018) je ob srednjih gladinah podze­mne vode njen prispevek k ekološkemu pretoku (E) 0,85 m3/s, kar presega Tennantovo (1976) mejo dobrih habitatnih recnih pogojev, t.j. 20 odstot­kov povprecnega letnega pretoka, ki je za obdob­je 1981–2010 na Savi med Mednim in Šentjako­bom ocenjeno na 0,47 m3/s (Tabela 2). Na kolicinsko obremenjenih vodonosnikih se je ocena prispevka podzemne vode k ekološkemu pretoku (E) izkazala za zelo obcutljiv parameter, ki terja podrobnejši napajalni model ob upošte­vanju podatkov o celotnem, baznem in ekološko sprejemljivem pretoku. Ocena napajanja podze­mne vode vodonosnika Ljubljanskega polja ob upoštevanju interakcije površinskih in podze­mnih voda sloni na konceptualni shemi nume­ricnega modela toka podzemne vode (Souvent et al., 2016), ocena ekološkega pretoka (Janža et al., 2016) pa je povzeta iz ocene kolicinskega stanja podzemnih voda (Andjelov et al., 2016). Ob upo­rabi scenarija petih sušnih let v zadnjem tridese­tletnem obdobju (Schlüter, 2006), kar je približek dvajsetemu centilu kolicine napajanja vodono­snikov v referencnem vodnobilancnem obdobju po vodnobilancnem modelu GROWA-SI, je pov­precni prispevek podzemne vode Ljubljanskega polja k ekološkemu pretoku 0,73 m3/s (Tabela 2). Ob srednjih gladinah podzemne vode v vodonos­niku Ljubljanskega polja s 3,11 m3/s modelirane­ga napajanja vodonosnika (Petauer & Hiti, 2017, 2018) in 1,0 m3/s crpanih kolicin podzemne vode je ob kolicinskem odtisu (GF) 29,2 km2 dosežena stopnja izkorišcenosti (GF/AA) 0,42. Stopnja izkorišcenosti podzemne vode v iz­branem casovnem obdobju med leti 2007 in 2014 z dvema hidrološkima ekstremoma zadnjih pet-desetih let (2011 in 2014) je pri ocenah za celot­na obmocja vodnih teles po pristopu Schlüterja (2006) ter Andjelova in sodelavcev (2016) najvecja na vodnih telesih podzemne vode VTPodV_3012 Dravska kotlina (0,28) ter VTPodV_1001 Savska kotlina in Ljubljansko Barje (0,20). Kot kolicin­sko najbolj ranljivo vodno telo izstopa Dravska kotlina, katere stopnja izkorišcenosti podzemne vode v suhem hidrološkem letu doseže vrednost 0,60 (Tabela 3). Povprecno gre v obdobju 2007– 2014 za stopnjo izkorišcenost podzemne vode v razponu od 0,08 v Krški kotlini do 0,28 v Dravski kotlini (Tabela 3, sl. 2). Kazalniki ranljivosti in onesnaženja podzemne vode S slabim kemijskim stanjem so v državnem nacrtu upravljanja voda (MOP, 2016) opredelje­na tri telesa podzemne vode: Savinjska, Dravska in Murska kotlina, ki skupaj predstavljajo 5,6 % površine države in 3,9 % obdobno razpoložljivih kolicin podzemne vode v Sloveniji. V nasprotju s to oceno splošni kazalniki trajnostne rabe pod-zemne vode (Tabela 1) prinašajo informacijo o razmeroma velikem deležu oskrbovalnih obmocij pitne vode s stalno potrebo po dezinfekciji vode (60 %), ki se z leti zvišuje (Sovic, 2017), visok je tudi delež obmocja Slovenije z najvišjo ranlji­vostjo na onesnaženje podzemne vode, izražene s hitrostjo toka podzemne vode (Prestor & Janža, 2016). Tudi v primeru vodonosnika Spodnje Savinj­ ske doline, študijskega obmocja enega od teles podzemne vode v slabem stanju, je delež obmocja Tabela 2. Kolicinski odtis in stopnja izkorišcenosti podzemne vode v vodonosniku Ljubljanskega polja. Table 2. Groundwater quantitative footprint and exploitation level in Ljubljansko polje aquifer. VODONOSNIK LJUBLJANSKEGA POLJA / LJUBLJANSKO POLJE AQUIFER CRPANJE PODZEMNE VODE / GROUNDWATER ABSTRACTION NAPAJANJE PODZEMNE VODE (Petauer & Hiti, 2017, 2018) / GROUNDWATER RECHARGE (Petauer & Hiti, 2017, 2018) PRISPEVEK PODZEMNE VODE K EKOLOŠKEMU PRETOKU REKE / GROUNDWATER CONTRIBUTION TO ENVIRONMENTAL STREAMFLOW KOLICINSKI ODTIS PODZEMNE VODE / GROUNDWATER QUANTITATIVE FOOTPRINT STOPNJA IZKORIŠCENOSTI PODZEMNE VODE / GROUNDWATER EXPLOITATION LEVEL C [m3/s] R [m3/s] Modflow E [m3/s] GF [km2] GF/A [-] A Povprecni hidrološki pogoji / Average hydrological conditions 0,47* 1,00 3,11 0,73** 29,2 0,42 0,85*** Opomba: * po pristopu iz Tennant (1976) / after approach from Tennant (1976) ** po pristopih iz Schlter (2006) in Andjelov in sod. (2016) / after approaches from Schlter (2006) and Andjelov et al. (2016) *** po pristopih iz Demuth (1993) in UL RS 97/09 (2009) / after approaches from Demuth (1993) and UL RS 97/09 (2009) Tabela 3. Stopnja izkorišcenosti podzemne vode v aluvialnih vodonosnikih vodnih telesih Slovenije. Table 3. Groundwater exploatation level in aluvial aquifers of groundwater bodies of Slovenia. TELO PODZEMNE VODE / GROUNDWATER BODY STOPNJA IZKORIŠCENOSTI PODZEMNE VODE / GROUNDWATER EXPLOATATION LEVEL SUHO HIDROLOŠKO LETO 2011 / DRY HYDROLOGICAL YEAR 2011 MOKRO HIDROLOŠKO LETO 2014 / WET HYDROLOGICAL YEAR 2014 OBDOBJE 2007–2014 / PERIOD 2007–2014 GF/A [-] A VTPodV_1001 Savska kotlina in Ljubljansko Barje 0,31 0,13 0,20 VTPodV_1002 Savinjska kotlina 0,17 0,04 0,10 VTPodV_1003 Krška kotlina 0,19 0,05 0,08 VTPodV_3012 Dravska kotlina 0,60 0,12 0,28 VTPodV_4016 Murska kotlina 0,37 0,07 0,17 Sl. 2. Stopnja izkorišcenosti podzemne vode po izbranih telesih podzemne vode Slovenije v obdobju 2007–2014. Fig. 2. Groundwater exploatation level for selected groundwater bodies of Slovenia in the period 2007–2014. z najvecjo ranljivostjo na onesnaženje podzemne vode z omenjeno metodo razmeroma visok: 45 %. Delež površja z najvecjo ranljivostjo pa je neko­liko nižji pri parametricni oceni splošne ranlji­vosti po metodologiji SINTACS in kot posterior- na verjetnost na nitratno onesnaženje podzemne vode po metodi teže evidenc WofE: 43 in 31 % (Uhan, 2011). Tudi odtis sive podzemne vode za onesnaženje z nitratom, razmerje med povprecnim deležem bremena onesnaženja, ki lahko doseže zasice-no obmocje vodonosnika, ter razliko med mejno vsebnostjo onesnaževala (50 mg/l) in vrednostjo tocke prevoja nad naravnim ozadjem (10 mg/l), je za celotno telo podzemne vode VTPodV_1002 Savinjska kotlina v okviru teh vrednosti. Glede na hidrološke razmere je bil odtis sive podzemne vode za onesnaženje z nitratom v VTPodV_1002 Savinjska kotlina v razponu od 0,22 v mokrem letu 2014 do 0,79 v sušnem letu 2011. V sušnem letu 2011 so odtisi sive podzemne vode za onesna­ ženje z nitratom presegali vrednost 1 kar v treh Tabela 4. Odtis sive podzemne vode v povezavi z vsebnostmi nitrata v aluvialnih vodonosnikih vodnih telesih podzemnih voda Slovenije. Table 4. Gray groundwater footprint related to nitrate concentration for alluvial aquifers of groundwater bodies of Slovenia. TELO PODZEMNE VODE / GROUNDWATER BODY STOPNJA NITRATNE ONESNAŽENOSTI PODZEMNE VODE (SUHO LETO 2011) / GROUNDWATER NITRATE POLLUTION LEVEL (DRY YEAR 2011) STOPNJA NITRATNE ONESNAŽENOSTI PODZEMNE VODE (MOKRO LETO 2014) / GROUNDWATER NITRATE POLLUTION LEVEL (WET YEAR 2014) ODTIS SIVE PODZEMNE VODE (OBDOBJE 2007-2014) / GRAY GROUNDWATER FOOTPRINT (PERIOD 2007-2014) WPL [-] VTPodV_1001 Savska kotlina in Ljubljansko Barje 0,46 0,17 0,28 VTPodV_1002 Savinjska kotlina 0,79 0,22 0,43 VTPodV_1003 Krška kotlina 1,38 0,31 0,67 VTPodV_3012 Dravska kotlina 1,81 0,35 0,75 VTPodV_4016 Murska kotlina 3,14 0,49 0,92 vodnih telesih podzemne vode: Krška kotlina (1,38), Dravska kotlina (1,81) in Murska kotlina (3,14) (Tabela 4). Regionalna analiza je pokaza-la visoke vrednosti odtisa sive podzemne vode za obremenitev z dušikom v sušnem letu 2011 tudi na nekaterih drugih obmocjih severovzhodne Slovenije (sl. 3). Razprava Sheme kazalnikov trajnostne rabe podzemne vode na nacionalni ravni, kot so jih razvili v de­lovni skupini UNESCO / IAEA / IAH (Vrba & Lipponen, 2007) (Tabela 1), sicer nudijo prvi pri­merljiv vpogled v stanje podzemnih voda ter pro-blematiko varovanja in rabe podzemnih vodnih virov, vendar lahko take ocene prekrijejo uprav­ljavsko pomembne informacije o kljucnih lokal­nih preobremenitvah. Tako lahko kljub razmeroma majhnemu dele­žu crpane kolicine razpoložljive podzemne vode za celotno Slovenijo (3,1 %), deleži v posame­znih vodnih telesih podzemnih voda predvsem v sušnih letih presegajo tudi 20 % razpoložljivih kolicin vodnega telesa, v posameznih kolicin­sko obremenjenih vodonosnikih, kot so npr. Lju­bljansko, Dravsko in Mursko polje, pa je ta delež še nekoliko višji. Ob upoštevanju kolicin iz evi­dence vodnih pravic za rabo podzemnih voda v najbolj obremenjenih vodonosnikih v Sloveniji v posameznih obdobjih že posegamo v drugo polo-vico razpoložljivih kolicin za crpanje podzemne vode (Tabela 3). Crpane kolicine podzemne vode iz aluvialnih vodonosnikov petih obravnavanih vodnih teles prestavljajo 45 % podeljenih vodnih pravic (Souvent & Cencur Curk, 2019). Ob tem pa je potrebno opozoriti na potrebo po pogloblje­ni analizi razpoložljivosti tudi lokalnih podze­mnih vodnih virov, predvsem s poudarkom na podrobnejši oceni prispevka podzemne vode za ekološki pretok. V raziskavi smo ugotovili velika odstopanja pri izracunih prispevkov podzemne vode za ekološki pretok, ki so posledica razlic­nih predpostavk in metodoloških pristopov, ob hkratnem neupoštevanju sezonske spremenlji­vosti. Zaradi tega je priporocljiva uporaba krite­rija trajnostnega upravljanja podzemnih voda, da s crpanjem podzemnih vodnih virov ne zmanjša-mo 10 % naravnega mesecnega baznega pretoka v površinskih vodotokih (Gleeson & Richter, 2017). Poznavanje hidrološkega režima oz. sezonske spremenljivosti kolicin obnovljive podzemne vode je kljucnega pomena tudi pri ocenah kemijskega stanja podzemnih voda. Kljub razmeroma stabil­ni dušikovi bilanci se vnosi dušika v vodonosnik v razlicno vodnatih hidroloških letih razlikujejo tudi za veckratnik, zato je interpretacija rezul­tatov monitoringa stanja podzemnih voda brez upoštevanja procesov v celotnem vodnem krogu lahko pomanjkljiva ali celo zavajajoca. Stopnja nitratnega onesnaženja podzemne vode je bila v analiziranem obdobju najvecja v letih 2011 in 2012, vzrokov za to pa ne najdemo v povecanem bremenu dušika, ampak v zmanjšanem napaja­nju, saj gre za najbolj sušno zaporedje dveh let zadnjega pol stoletja. Za sistematicno spremljanje doseganja trajno­stnih ciljev pri crpanju in ohranjanju kakovosti podzemnih voda priporocamo uvedbo kazalni­kov vodnega stresa in vodnega odtisa, ki zelo na­zorno pokažejo clovekove vplive na stanje narav­nih vodnih virov (Hoekstra, 2003; Hoekstra et al., 2011). Spremljanje kazalnikov se mora opreti na rezultate vodnobilancnega modeliranje in študije pritiskov in vplivov v upravljavsko primerni pro-storski in casovni skali. Sl. 3. Stopnja nitratne onesnaženosti podzemne vode v Slovenije v obdobju 2007–2014 po regionalnem modelu GROWA-SI / DENUZ-WEKU v prostorski skali 100 × 100 m. Fig. 3. Groundwater nitrate pollution level in Slovenia in the period 2007–2014 after the GROWA-SI / DENUZ-WEKU regio­ nal model in the spatial resolution 100 × 100 m. Sklep Pri ocenjevanju doseganja trajnostnih ciljev upravljanja podzemnih voda v Sloveniji smo kot kazalnik kolicinskega stresa in nitratne obreme­njenosti podzemnih voda prvic v Sloveniji upo­rabili koncept vodnega odtisa za podzemne vode, ki naj bi podpiral ucinkovitejše nacrtovanje upravljanja in strateški razvoj dolgorocnih okolj­skih politik. V študiji je bila ob uporabi rezulta­tov regionalnega bilancnega modeliranja za pli­tve vodonosnike celotnega obmocja Slovenije in modeliranja toka podzemne vode na ravninskih aluvialnih vodonosnikih preizkušena metodolo­ gija kolicinskega odtisa podzemne vode in odtisa sive podzemne vode. Rezultati izracunanih sto­penj izkorišcenosti podzemne vode na nekaterih vodonosnikih presegajo polovico razpoložljivih kolicin, stopnja nitratnega onesnaženja podze­mne vode pa že presegajo mejo trajnostnega va­rovanja. Rezultate smo primerjali z dosedanjimi oce­nami stanja voda po posameznih vodnih telesih podzemnih voda in ugotovili, da uporaba kon­cepta kolicinskega stresa in kolicinskega odtisa podzemne vode z upoštevanjem površine napa­jalnega obmocja predstavlja koristno dopolnitev dosedanje ocene kolicinskega stanja podzemnih voda, odtis sive pozemne vode pa ob upoštevanju vodne bilance in hidrokemicnega ozadja prinaša možnost povsem novega vpogleda v prostorsko in casovno shemo obremenjevanja vodnih teles podzemnih voda v Sloveniji. Koncept odtisa sive vode bi bilo v prihodnje koristno uporabiti za vse parametre monitoringa, ki ogrožajo dobro stanje podzemnih voda, in preko teh kazalnikov spre­mljati ucinke ukrepov v lokalnem in regional-nem merilu ter sprotno usmerjati prostorsko in okoljsko politiko za doseganje dobrega stanja in trajnostnega upravljanja podzemnih voda v Slo­veniji. Doseganje trajnostnih ciljev v zvezi z zagota­vljanjem dostopa do vode in sanitarne ureditve ter trajnostnim gospodarjenjem z vodnimi viri do leta 2030 bo odvisno predvsem od realiza­cije ukrepov, ki jih bo prinesel naslednji nacrt upravljanja voda. Zato naj bi nacrt upravljanja voda za obdobje 2022–2027 temeljil na oceni sta­nja po posameznih vodnih telesih, nadgrajeni z letnimi in obdobnimi bilancnimi analizami iz­korišcenosti in onesnaženosti podzemne vode na posameznih najbolj obremenjenih delih vodnih teles podzemne vode. V tem primeru bo ukrepe za doseganje ciljev okvirne direktive o vodah mogoce ucinkovito usmerjati v opredeljevanje in zmanjševanje lokalnih pritiskov in vplivov, ki ogrožajo doseganje trajnostnih ciljev na podrocju podzemnih voda v Sloveniji. Zahvala Zasnova in prvi izracuni kazalnikov doseganja trajnostnih ciljev z vidika upravljanja in varovanja podzemnih voda v Sloveniji temelji na številnih simu­lacijah regionalnih modelskih sistemov GROWA-SI in DENUZ-WEKU, ki so rezultati nemško-slovenskega raziskovalnega projekta med Agencijo RS za okolje in Forschungszentrum Jülich. Kljucno vlogo pri prenosu teh regionalnih modelskih sistemov v slovenski pros-tor sta imela nemška raziskovalca dr. Frank Wendland in dr. Ralf Kunkel. Avtorja clanka se za njuno dolgole­tno odlicno sodelovanje iskreno zahvaljujeva. Reference Andjelov, M., Kunkel, R., Uhan, J. & Wendland, F. 2014: Determination of nitrogen redu­ction levels necessary to reach groundwa­ter quality targets in Slovenia. 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CC Atribution 4.0 License https://doi.org/10.5474/geologija.2019.014 Pregled uporabe georadarja na krasu Application of ground penetrating radar in karst environments: An overview Teja CERU1 & Andrej GOSAR2,3 1Geološki zavod Slovenije, Dimiceva ul. 14, SI-1000 Ljubljana, Slovenija; e-mail: teja.ceru@geo-zs.si 2Agencija RS za okolje, Urad za seizmologijo,Vojkova cesta 1b, SI-1000 Ljubljana, Slovenija 3Univerza v Ljubljani, Naravoslovnotehniška fakulteta, Aškerceva 12, SI-1000 Ljubljana, Slovenija Prejeto / Received 4. 11. 2019; Sprejeto / Accepted 17. 12. 2019; Objavljeno na spletu / Published online 24. 12. 2019 Kljucne besede: georadar, kras, jama, pogrezanje, epikras, kraški vodonosnik, kamnolom, brezstropa jama, jamski sedimenti Key words: ground penetrating radar (GPR), karst, cave, subsidence, epikarst, karst aquifer, quarry, unroofed cave, cave sediments Izvlecek Kras kot kompleksen in heterogen sistem predstavlja za georadar velik izziv. Kljub vsemu pa lahko z dobro nacrtovanimi georadarskimi raziskavami pridobimo dodatne informacije o plitvem podpovršju, kjer se odvija vecina kraških procesov. Zaradi specificnosti kraškega površja so v uvodnem delu predstavljene nekatere ovire in prilagoditveni pristopi pri raziskavah na krasu. Analiza pregleda objavljene literature je pokazala, da se georadar v kraških okoljih najpogosteje uporablja za zaznavanje jam in obmocij pogrezanj ter pri preprecevanju nenadnih porušitev tako v urbanih obmocjih kot tudi pri gradbenih posegih v prostor. Georadar se uporablja tudi pri raziskavah kraških vodonosnikov, epikrasa in raziskavah v kamnolomih. Poleg uveljavljenih aplikacij so predstavljene nekatere še neuveljavljene aplikacije, kot je uporaba georadarja pri raziskavah brezstropih jam in jamskih sedimentov. Glavni namen clanka je prikazati in ovrednotiti možnosti uporabe georadarja v razlicnih kraških okoljih in spodbuditi njegovo uporabo za nekatere nove aplikacije in opozoriti na nujnost interdisciplinarnega pristopa v takšnih študijah. Abstract Karst as an extremely complex and heterogeneous system, that presents a great challenge for the ground penetrating radar (GPR). However, properly planed GPR surveys can provide additional information about the shallow subsurface, where most karst processes take place. Due to the specific nature of the karst terrain, the introductory part presents some obstacles and adaptive approaches to karst research. An analysis of the published literature revealed that the GPR is most commonly used for detecting caves and subsidence areas and for preventing collapses in urban areas and for construction interventions. This is followed by exploration of karst aquifers, epikarst and quarry research. Some non-established applications are also presented, such as the use of a georadar in exploration of unroofed caves and cave sediments. The main purpose of this article is to demonstrate and evaluate the possibilities of using a georadar in different karst environments, to encourage its use in some new applications, and to emphasize the necessity of an interdisciplinary approach in such studies. Uvod Kraški sistem sodi med najkompleksnejša geo­loška okolja pri hidrogeoloških, geotehnicno-in­ženirskih in okoljskih raziskavah. Zaradi hete­rogenosti in nepredvidljivosti predstavlja kraški sisitem za georadarske raziskave velik izziv, a z leti se njegova uporaba kljub vsemu veca. Z vidi­ka zašcite podzemne vode na kraških obmocjih, ter zaradi ostalih nevarnosti, ki so posledica zakrasevanja (npr. nestabilnost tal), je vse vecje zavedanje pomembnosti razumevanja kraških procesov vodilo v hiter porast raziskav v zadnjih dveh desetletjih (Gutiérrez et al., 2014). Kljuc­na prednost georadarja v primerjavi s seizmic­no refrakcijo/refleksijo in elektricno upornostno tomografijo (ERT) je visoka locljivost, ki omogo-ca natancen vpogled v strukturo podpovršja ter relativno hitre in enostavne meritve (Schrott & Sass, 2008). Medtem ko z geološkimi, hidrogeolo­škimi in geomorfološkimi metodami raziskujemo le površje krasa oz. pridobimo le tockovne infor­macije iz globine (vrtine), nudijo geofizikalne me-tode zvezen niz podatkov. Kras pokriva 12 % vsega površja Zemlje in je zaradi svoje raznolikosti in posebnosti predmet številnih študij v okviru temeljnih ali aplikativ­nih raziskav na razlicnih znanstvenih podrocjih (Andreo et al., 2010). Dejstvo, da karbonatne in evaporitne kamnine pokrivajo 20 % površja in da je cetrtina prebivalstva odvisna od oskrbe pitne vode v kraških vodonosnikih (Gutiérrez et al., 2014), je vodilo v vse vecji interes za raziskovanje tega sistema. Zaradi obcutljivosti kraškega siste-ma so v takšnih okoljih potrebne posebne metode raziskav za zašcito pred okoljsko-inženirskimi problemi kot so onesnaževanje kraških vodonos­nikov, pogrezanje tal, nastanek udornic in jam. V zadnjem casu je bilo objavljene veliko pregledne literature, ki združuje in povezuje temeljno vede­nje z aplikativnimi študijami na kraškem površju (Andreo et al., 2010; 2015; Waltham et al., 2005). Še pomembnejše so raziskave krasa na urbanih obmocjih in pri inženirsko-geotehnicnih posegih v prostor (kamnolomi, gradnja cest in predorov) za zmanjševanje geološko pogojenih nevarnosti (geohazard). V zadnjih 30 letih se je uporaba georadar­ja uveljavila na številnih podrocjih, cemur so v zadnjih 10 letih sledile objave preglednih clan-kov za razlicne aplikacije. Eden izmed prvih ce­lovitih preglednih clankov na podrocju uporabe v geologiji obravnava uporabo georadarja v sedi­mentologiji (Neal, 2004). Pregled uporabe geofizi­kalnih metod pri geomorfoloških raziskavah sta podala Schrott & Sass (2008) in poudarila pomen integracije razlicnih metod ter opisala njihove prednosti in omejitve. V zadnjih nekaj letih so bili objavljeni tudi pregledni clanki na podrocju gradbeništva (Wai-Lok Lai et al., 2018). Zajícová & Chuman (2019) sta podala pregled uporabe ge­oradarja v študijah tal, kjer obravnavata doloce­vanje vsebnosti vode, stratigrafije tal, vsebnosti soli in strukture tal, zaznavanje drevesnih ko­renin in koreninske biomase. Pregled raziskav z razlicnimi geofizikalnimi metodami na krasu so povzeli Chalikakis et al. (2011), ki so obravnavali prednosti in omejitve za nekatere najpogostejše aplikacije. Podrobnejši pregled, ki bi obravnaval razlicne aplikacije georadarja na krasu, še ni bil objavljen. Ta prispevek predstavlja krajši povzetek teo­rije in raziskav, ki so bile narejene v okviru dok­torskega dela (Ceru, 2019). V uvodnem delu so podane osnove, ki so pomembne za razumevanje delovanja georadarja ter njegove uporabe na kra­su. Sledi analiza pregleda objavljene literature v bazah Web of Science (WoS) in Scopus. Jedro clanka predstavlja pregled raziskav po razlicnih aplikacijah s primeri radargramov. Predstavljene so nekatere najbolj uveljavljene uporabe ter tudi nekatere nove možnosti, ki so bile raziskane v okviru doktorata, kot je zaznavanje brezstropih jam in jamskih sedimentov z georadarjem. Osnove delovanja georadarja Georadar oddaja kratke pulze elektromagne­tnega (EM) valovanja v podpovršje, kjer se del vpadnega valovanja odbije (refleksija) zaradi kontrasta dielektricnih lastnosti na meji razlic­nih snovi (Blindow et al., 2007). Globinski doseg georadarja je poleg elektricnih lastnosti materia-la v najvecji meri odvisen od frekvence oddajnih anten, zato se v praksi glede na ciljno problema­tiko uporabljajo georadarski sistemi razlicnih frekvenc. Za uporabo na krasu so najprimer­nejši nizkofrekvencni georadarski sistemi (25– 250 MHz), ki omogocajo vecji globinski doseg ob še sprejemljivi locljivosti. Pri plitvejših raziska­vah pa je zaželeno, da se meritve dopolnjujejo tudi z višjefrekvencnimi antenami (. 250 MHz). Metoda georadarja je po principu delovanja podobna refleksijski seizmiki in tehnikam so-narjev (Davis & Annan, 1989). Metoda temelji na penetraciji EM valov, ki jih v kratkih impulzih pošiljamo z oddajno anteno v tla (Davis & Annan, 1989). Del vpadnega valovanja se na meji razlic­nega materiala odbije zaradi razlicnih elektric­nih lastnosti (Blindow et al., 2007), kjer ga na površju zazna sprejemna antena (sl. 1). Pri tem se meri dvojni cas potovanja valov (ang. two-way travel time) od oddajne antene do mejnih ploskev (reflektorji) in nazaj do sprejemne antene. Sl. 1. Shematski prikaz delovanja georadarja. Fig. 1. Schematic principle of GPR measurement. Najpomembnejši lastnosti, ki vplivata na od­bojnost na meji razlicnih plasti in na globinski doseg valovanja, sta dielektricnost (e) in elektric­na prevodnost (s) snovi (Blindow, 2006). Na elek­tricne lastnosti nevezanega sedimenta v najvecji meri vpliva prostorninski delež vode, na spre­membe elektricnih lastnosti kamnin pa vrsta ka­mnine in delež razpok zapolnjenih z vodo in/ali zrakom. Razlike v elektricnih lastnostih materi­alov vplivajo na hitrost in dušenje ter delež odbi­tega EM valovanja. Le dovolj velik kontrast di­elektricnih lastnosti med razlicnimi snovmi in s tem sprememba v hitrosti EM valovanja povzro-ci, da pride do odboja na meji, kar omogoca raz­likovanje med razlicnimi objekti v podpovršju (Reynolds, 2011). Locljivost metode ter izguba energije in dušenje signala Ker se EM valovanje od oddajne antene širi v obliki konusnega stožca, se amplituda zaradi sfe­ricnega razširjanja valovanja z oddaljevanjem od antene zmanjšuje (Reynolds, 2011). Zato se loclji­vost in posledicno velikost objekta, ki ga lahko zaznamo, z globino spreminja. Vertikalna loclji­vost georadarskega sistema je funkcija predvsem frekvence in teoreticno velja, da je vertikalna lo­cljivosti enaka Ľ valovne dolžine (./4). V praksi je manjša od teoreticne, saj nanjo vplivajo še šte­vilni drugi dejavniki. Horizontalna locljivost pa je odvisna od frekvence in dielektricnih lastnosti snovi. V tabeli 1 so podane vrednosti za vertikal-no in horizontalno locljivost za dva razlicna ma-teriala in dve frekvenci, ki se najpogosteje upo­rabljata pri raziskavah na krasu. Vidimo, da se horizontalna locljivost z globino hitro manjša. Na izgubo energije in dušenje EM valovanja vpliva veliko dejavnikov. V prvi vrsti na zmanj­šanje amplitude vpliva sama oblika oz. geometrija georadarskega signala. Ko potuje od antene v tla, se ustvari t.i. talni spoj (ang. ground coupling), kjer pride do prvih izgub EM valovanja. Izguba je odvisna tudi od znacilnosti in kakovosti georadar­skega sistema ter frekvence, saj so višje frekvence podvržene vecjemu dušenju. Poleg tega pa na du­šenje vplivajo predvsem dielektricne, elektricne in magnetne lastnosti kamnin. Na te pa vplivajo poroznost, zrnavost, mineralna sestava, prisotnost vode, prisotnost soli in ostale znacilnosti materia-la, zato je težko vnaprej predvideti vse dejavnike, ki imajo vpliv na razširjanje EM valovanja. V praksi se na kraškem terenu izkaže, da ima na dušenje signala velik vpliv heterogenost siste-ma. Praznine, neraven in nezvezen kontakt ma­ticne podlage s tlemi z vmesnimi globokimi žepi in nehomogenosti znotraj karbonatnih kamnin povzrocajo sipanje energije in vplivajo na zmanj­šanje energije signala. Veliko omejitev na krasu predstavljajo tudi drobnozrnati sedimenti, ki za­polnjujejo depresije, jame in kraške žepe, saj zara­di svojih lastnosti pomembno vplivajo na izgubo signala. Sedimenti in tla na krasu vsebujejo pre­cejšen delež glinenih mineralov, ki bistveno vpli­vajo na dušenje signala, še posebej ob vecji pri­sotnosti vode. Kljub temu, da tla na karbonatnih tleh navadno niso debela, se je izkazalo, da je glo­binski doseg 50 MHz antene bistveno manjši (med 5–20 m, v povprecju pa med 8–15 m) v primerjavi z meritvami v kamnolomih, kjer je teren raven in na površju ni sedimentov (globinski doseg do 30 m). Na razgibanem površju prihaja do izgub energije tudi zaradi slabega stika med anteno in tlemi. Tabela 1. Teoreticna locljivost 50 in 250 MHz antene pri razlicnih vrednostih dielektricne konstante na doloceni globini. Table 1. Theoretical resolution of 50 and 250 MHz antenna with different dielectric constants at certain depth. Globina (m) Depth (m) Vertikalna locljivost (m) Vertical resolution (m) Horizontalna locljivost (m) Horizontal resolution (m) 50 MHz 250 MHz 50 MHz 250 MHz 50 MHz 250 MHz Apnenec Limestone .= 7 (v= 0,11 m/ns) 5 2 1,134 0,227 2,335 0,820 10 4 1,134 0,227 4,102 1,528 15 6 1,134 0,227 5,870 2,235 20 8 1,134 0,227 7,638 2,942 30 10 1,134 0,227 11,173 3,649 *Povprecna tla Average soil .= 16 (v= 0,075 m/ns) 5 2 0,750 0,15 1,588 0,560 10 4 0,750 0,15 2,800 1,045 15 6 0,750 0,15 4,013 1,530 20 8 0,750 0,15 5,226 2,015 30 10 0,750 0,15 7,651 2,500 *povprecna tla (average soil): Povprecna vrednost v razponu za razlicna tla (average value in the range for different soils). V tabeli 2 so strjene glavne prednosti in nekatere omejitve georadarja na krasu. Tabela 2. Prednosti in pomanjkljivosti georadarske metode. Table 2. Advantages and limitations of the GPR method. PREDNOSTI (Advantages) OMEJITVE (Limitations) • Nedestruktivnost - še posebej pomembna v urbanih okoljih • Non-destructiveness - particularly important in urban en­vironments • Globinski doseg je majhen v visoko prevodnih okoljih (sedi­menti z vecjim deležem gline, prisotnost vode) • The depth of penetration is limited in highly conductive en­vironments (clayey sediments, presence of water) • Najvecja locljivost med vsemi geofizikalnimi metodami • The highest resolution out of all geophysical methods • Zaradi stika antene s tlemi mora biti teren raven in enako­meren, kar je na kraškem površju redkost • Because the antenna must be in contact with the ground, the terrain must be level and even, which is rare in karst • Z mrežo vzporednih in precnih profilov z nadaljnjo obdela- • Interpretacija radargramov je kompleksna, sploh v vo in modeliranjem dobimo 3D modele kraškem sistemu • A network of parallel and transverse profiles with further • The interpretation of radargrams is complex, especially in processing and modelling can create 3D models the karst system • Relativno hitre in enostavne meritve v primerjavi z nekate- • Metoda ni primerna za materiale s podobnimi dielek­ rimi ostalimi geofizikalnimi metodami tricnimi lastnosti • The measurements are relatively quick and easy compared • The method has limitations if dielectric properties of mate- to other geophysical methods rials are similar • Zvezen niz podatkov v primerjavi z raziskovalnim vrtanjem • Continuous data information compared to drilling data • Uspešnost metode je odvisna od danih pogojev na terenu, pri cemer ima velik vpliv vsebnost vlage (padavine) • The success of the method depends on field conditions, where moisture content (precipitation) has a high influence • Prirocna metoda pri preliminarnih raziskavah zaradi rela- • Pri nešcitenih antenah lahko odboji od nadpovršinskih ob- tivno enostavnih in hitrih meritev jektov onemogocijo interpretacijo radargramov • A convenient method for preliminary research due to rela- • For unshielded antennas, reflections from surface objects tively simple and fast measurements may prevent the interpretation of the radargrams Izvajanje meritev na kraškem terenu Kraški teren je vecinoma neraven in težko prehoden, kar za georadarske meritve predsta­vlja precejšen omejitveni dejavnik. Pred zacet­kom meritev zato traso profilov ocistimo, kolikor je to mogoce, da omogocimo cim boljši stik ante-ne s tlemi. Ce je teren dovolj raven, se uporabljajo toge šcitene antene, s katerimi pa je premikanje po terenu polnem kamenja in škrapelj nemogoce ali pa je stik antene s tlemi preslab. Za vecino raziskav v okviru doktorata je bila zato upora­bljena georadarska oprema Mala ProEx (Šved­ska) z 50 MHz RTA (»Rough Terrain Antenna«) nešciteno (ang. unshielded) anteno. Ta se je za ge­ološke aplikacije izkazala kot zelo uspešna tako zaradi globinskega dosega kot zaradi samega sis-tema, ki omogoca meritve tudi na bolj razgiba­nih in porašcenih obmocjih. Meritve smo glede na namen in terenske pogoje dopolnjevali tudi s šciteno (ang. shielded) 250 MHz anteno. Glavna prednost RTA sistema je upogljivost cevi, ki vkljucuje oddajno in sprejemno ante-no. Takšna konfiguracija omogoca meritve na škrapljastem terenu (sl. 2a). Po drugi strani pa takšen sistem onemogoca šcitenje sevanja anten, kar pomeni, da oddajna antena EM valovanje od­daja v vse smeri in dobimo tudi nadpovršinske odboje, ki v neugodnih pogojih lahko zakrivajo reflektorje v podpovršju. Ce je mogoce, zato me-ritve nacrtujemo v mesecih, ko na drevesih ni listja in bujne podrasti ter tako zmanjšamo vpliv Sl. 2. Georadarski sistem Mala ProEx z a) nešciteno 50 MHz RTA (»Rough Terrain Antenna«) anteno; b) šciteno 250 MHz anteno. Fig. 2. GPR system Mala ProEx with a) an unshielded 50 MHz RTA (»Rough Terrain Antenna«); b) a shielded 250 MHz antenna. nadpovršinskih odbojev. Poleg tega je takrat te­ ren tudi bolj prehoden in posledicno stik antene s tlemi boljši. Izogibamo se tudi daljnovodom, og­rajam in ostalim objektom na površju, ki lahko predstavljajo izvor nadpovršinskih motenj. Za plitvejše raziskave smo meritve dopolnje­vali tudi s šciteno 250 MHz anteno (sl. 2b). Od­dajna in sprejemna antena sta šciteni v skupnem ohišju, zato antena oddaja signal samo v smeri tal. S tem je omogoceno selektivno izboljšati žele­ne signale in zmanjšati motnje. Poleg prednosti pa se možnost pojava veckratnega odbijanja signala (ang. ringing) zaradi sistema znatno poveca. Šci­tenje antene nikoli ni popolno, zato vcasih tudi pri šcitenih antenah dobimo nadpovršinske odbo­je (Annan, 2009), ki se jih lahko napacno interpre­tira. Zato je uporaba nešcitenih anten vcasih bolj­ša izbira, ce nam pogoji na terenu to omogocajo. Izbira antene in primerjava radargramov razlicnih frekvenc Ustrezna izbira frekvence antene georadar­skega sistema je kljucnega pomena pri nacrto­vanju meritev, saj frekvenca vpliva na globinski doseg in locljivost metode. Glede na kontrast fi­zikalnih lastnosti ciljne strukture (jama, vrtaca, cevi, prelom, geološka bariera…) v primerjavi z okolno kamnino, ciljno globino in velikostjo pro-ucevane strukture, se odlocimo za ustrezno fre­kvenco. Pred izbiro ustrezne antene je potrebno vedeti v kakšnih pogojih se kraške oblike pojav­ ljajo, približno kakšnih dimenzij so, ter na kateri globini pricakujemo pojav, ki ga želimo zaznati. Ce pa je le mogoce in smiselno, meritve izvedemo z vec razlicnimi frekvencami. Za primerjavo radargramov razlicnih fre­kvenc sem izbrala dva primera, izmerjena v raz­licnih terenskih pogojih. Prvi profil (sl. 3) prika­zuje obmocja povezav med segmenti brezstrope jame na otoku Krk v karbonatih (Ceru et al., 2018a). Zaradi velikega kontrasta v dielektricni konstanti med sedimenti brezstropega jamske­ga sistema in okoliškim kraškim terenom se ta obmocja jasno odražajo tako na radargramih 50 MHz kot tudi 250 MHz antene. Obmocja anomalij (A in B) se jasneje vidijo na radargramu 50 MHz antene, kjer je dušenje signala na obmocjih vec­je debeline sedimentov izrazitejše v primerjavi z 250 MHz anteno. Na radargramu 250 MHz an-tene se zaradi boljše locljivosti antene lepo vidi skledasto obliko povezav (povecan detajl slike 3). Drugi primer (sl. 4) prikazuje georadarski profil preko vrtace v pleistocenskem konglome­ratu na Kranjskem polju (Ceru et al., 2017), kjer so lepo vidne razlike med 50 MHz nešciteno in 250 MHz šciteno anteno. Pri 250 MHz anteni ne dobimo nadpovršinskih odbojev od dreves. Za­radi velike debeline tal je globinski doseg obeh anten manjši kot v primeru brezstropih jam v apnencih. Ce primerjamo radargrama obeh fre- Sl. 3. Primerjava radargramov 50 in 250 MHz antene, kjer anomaliji A in B predstavljata vecjo debelino sedimentov (povezava segmentov brezstrope jame). Radargram 250 MHz antene zaradi boljše locljivosti kaže skledasto obliko na sredini anomalije B. Fig. 3. Comparison of the 50 and 250 MHz radargrams, where interpreted anomalies A and B represent greater thickness of sediments (the connections between segments of an unroofed cave). The radargram of the 250 MHz antenna shows a bowl-sha­ ped structure in the centre of anomaly B. Sl. 4. Primerjava radargramov dveh frekvenc (50 in 250 MHz) na primeru profila cez vrtaco v konglomeratu (Ceru et al., 2017). Fig. 4. Comparison of radargrams of two frequencies (50 in 250 MHz) in the case of a profile over a doline in a conglomerate (Ceru et al., 2017). kvenc, 250 MHz antena poda bistveno manj in-formacij kot 50 MHz antena. Pedološki horizont Bt je na profilu 50 MHz antene zvezen, medtem ko pri 250 MHz anteni ni v celoti sledljiv. Prav tako niso jasni in izraziti odboji od praznin v dnu vrtace, kot je to vidno pri 50 MHz anteni. Iz obeh predstavljenih primerov vidimo, da je potrebno vsak teren obravnavati loceno, prav tako je zaželena uporaba vec frekvenc. Testne meritve pri umerjanju metode so pomembne, saj nam pokažejo, katera frekvenca je primernejša za dane terenske pogoje in cilj raziskav. Obdelava podatkov Striktna navodila za obdelavo georadarskih podatkov ne obstajajo, razen za nekatere osnovne postopke kot je odstranitev zamika signala in do-locitev nicelnega casa, ki so nujni. Izbira drugih postopkov in njihovega zaporedja pa je prilagoje­na konkretnim podatkom. Pri izbiri postopkov je zelo pomembno dobro poznavanje lastnosti pre-ucevanega obmocja. Nekateri napredni postopki obdelave lahko podajo boljše informacije, ce je Tabela 3. Zaporedje postopkov obdelave radargramov. Table 3. Processing sequence of radargrams. POSTOPKI OBDELAVE (Processing steps) • odstranitev zamika signala (»subtract mean-dewow«) • dolocitev nicelnega casa pri prvem negativnem vrhu signala s postopkom korekcije maksimalne faze (»correct max. phase«) in prestavitvijo nicelnega casa (»move start time«) • odstranitev ozadja (»background removal«) • funkcija ojacenja amplitude (»amplitude correction«): – upadanje energije (»energy decay«) – avtomatsko ojacenje amplitude (»automatic gain control–AGC«) – rocno ojacenje amplitude (»manual gain (y)«) • pasovno prepustno filtriranje (»bandpass frequency filtering«) • 2D filtriranje (»median xy filter« in »subtracting average«) ciljna struktura dobro definirana, in kjer vnap­rej poznamo velikost, obliko objekta in lastnosti podpovršja, da so postopki sploh smiselni, kar pa je pri raziskavah na krasu pogosto nemogo- ce. Zaradi slabšega globinskega dosega pri vecini raziskav, sem nekoliko vec casa namenila oja-cenju amplitude. Vsak radargram sem obdelala z razlicnimi funkcijami in nastavitvami, da sem pridobila najboljši rezultat. Vsako obmocje zahteva specificno obdelavo, a pri vecini radargramov sem uporabila zaporedje postopkov, ki so prikazani v tabeli 3. Postopki so prikazani na primeru radargrama obdelanem v programu ReflexW (sl. 5). Anomalija kaže na povezavo med dvema vecjima depresija-ma (okvir na sl. 5). Obmocje vecje debeline sedi­mentov dokazuje povezavo teh oblik v brezstrop jamski sistem. Nekateri naprednejši postopki kot je migracija in dekonvolucija so bili uporabljeni za posebne namene. Z vzporedno mrežo profilov lah­ko pridobimo 3D model podpovršja, kjer dobimo predstavo o razširjanju iskanih objektov v prosto­ru. Programska okolja poleg 3D modelov omogo-cajo tudi prikaz prerezov po globini in dolžini. Uporaba georadarja na krasu Georadar se je v zacetku uporabljal za reše­vanje razlicnih geoloških problemov, predvsem pri inženirskih in okoljskih raziskavah ter na podrocju glaciologije. Šele kasneje se je metoda uveljavila na številnih drugih podrocjih, med drugim tudi za raziskave na krasu. Za pregled uporabe georadarja na krasu sem uporabila objavljeno literaturo v podatkovnih bazah Scopus in Web of Science (WoS). Z iskal­nim vnosom (title-abs-key (gpr) or title-abs-key (ground and penetrating and radar) and title-ab-s-key (karst*)) dobimo v bazi Scopus 297 zadetkov in v bazi WoS z iskalnim vnosom, ki je ekviva­lenten iskanju v Scopus bazi (topic (title, abstra­ct, author keywors, keywords Plus): (ground Sl. 5. Zaporedje postopkov obdelave profila 50 MHz antene, ki je bil uporabljen pri vecini profilov: a) surov radargram; b) od­stranitev zamika signala; c) dolocitev nicelnega casa; d) odstranitev ozadja; e) rocno ojacenje amplitude; f) pasovno prepustno filtriranje. Vpliv postopka na izbrano sled (oznacena rdece) je prikazan desno ob profilu. Fig. 5. Sequence of processing steps for the 50 MHz antenna that was used for most profiles: a) raw radargram; b) subtract me­an-dewow; c) determination of time zero; d) background removal; e) manual amplification of amplitude; f) bandpass filtering. The impact of processing steps on the marked trace (red line) is shown to the right of the profile. penetrating radar or gpr) and topic: (karst*)), 244 zadetkov. Glavna razlika med zadetki v obeh bazah je delež prispevkov s konferenc. V bazi Scopus je zavedenih vec prispevkov s konferenc, nabor clankov pa je podoben. Po pregledu vsebin clankov in prispevkov je ocitno, da je vecina pri­spevkov na konferencah s podrocja gradbeništva in geotehnike, medtem ko so vsebine clankov bolj raznolike in obravnavajo tudi nekoliko bolj te­meljne krasoslovne tematike. 45 40 Najvecji porast objav sledimo po letu 2009, od takrat dalje je letno število prispevkov s konfe­ renc in clankov bolj ali manj konstantno (sl. 6). Graf slike 7 prikazuje število objav po drža­vah, za katere pa so znacilni razlicni interesni cilji raziskav. V ZDA prevladujejo raziskave ob-mocij pogrezanja (ang. subsidence) oz. nenadnih udorov (ang. hazardous sinkhole) in raziskave hidrogeoloških znacilnosti v kraških vodonosni­kih. Na Kitajskem je uporaba georadarja pove­ 35 31 29 29 28 30 26 25 22 18 20 17 16 13 15 12 11 10 10 9 10 6 5 0 41 37 35 35 Sl. 6. Prikaz števila objavl­jenih del po obdobjih v ba­ zah Scopus in WoS. Fig. 6. Number of published items by period in Scopus and WoS databases. Št. objavljenih del No. of published items Scopus WoS y No. of published items r r r r r r .  Sl. 7. Število objavljenih del po državah v obdobju med 1987–2019. Fig. 7. The number of published items by countries in the period 1987–2019. zana predvsem z gradbeno-inženirskimi posegi v prostor. Vecina raziskav v Španiji je osredotoce­na na preucevanje procesov zakrasevanja v eva­poritnih kamninah, kjer se georadar aplicira za zaznavanje in dolocevanje obsega obmocij pogre­zanja v sadri in anhidritu. V Italiji prevladujejo arheološke raziskave v zakraselih apnencih in študije zaznavanja plitvih jam in obmocij nesta­bilnosti. Tudi v Sloveniji je bilo do sedaj uspešno izvedenih že nekaj študij z nizkofrekvencnim ge­oradarjem za detekcijo kraških pojavov v apnen­cih. Za analizo uporabe georadarja na krasu sem v bazi Scopus posamicno pregledala in izbrala 227 relevantnih clankov in prispevkov z razlicnih konferenc. V nabor objavljenih del sem vkljucila vse raziskave, ki obravnavajo vsebine povezane s krasom, in jih uvrstila v kategorije glede na glavni Obmocjaugrezanj,udornice(subsidence,sinkholes) Jame, praznine (caves, voids) Tektonskastruktura,kamnolomi(tectonicstructure,quarries) Tla/podlaga,epikras(soil/bedrock,epikarst) Arheologija (archeology) Hidrogeologija(hydrogeology) Ostalo(other) Analiza signala,modeliranje(signalanalyses, modelling) Inženirskeraziskave(engineeringinvestigations) 100 90 80 1987-1997 2000-2005 2006-2013 2014-2019 Sl. 8. Pregled objavljenih del po obdobjih glede na glavni cilj oz. podrocje raziskave. Fig. 8. Review of published items by period according to the main objective of the research problem. Wcilj raziskave (sl. 8). Iz grafa je razvidno, da se je georadar sprva uporabljal predvsem za za­znavanje praznin in jam, strukturno tektonskih znacilnosti kamnin in pri raziskavah v kamnolo­mih ter za raziskave epikraške cone oz. za dolo- canje meje tla/podlaga. Precejšen delež raziskav je bil že v zacetku uporabe georadarja na krasu usmerjen na zaznavanje obmocij ugrezanj. Z leti je število aplikacij naraslo in pricele so se razi­skave kraških vodonosnikov in študije v okviru arheoloških raziskav, ki pa so najmanj povezane s kraškimi vsebinami. Po letu 2006 do danes pre­vladujejo georadarske raziskave pri inženirsko­geotehnicnih posegih v prostor, tovrstne študije vecinoma obsegajo zaznavanje praznin in struk­turno-tektonske znacilnosti kamnin. Poleg tega je vse vec raziskav, ki se ukvarjajo z analizo si­gnala in z modeliranjem EM valovanja. Pregled po razlicnih aplikacijah Vecina raziskav povezanih s kraškimi pojavi je aplikativnega znacaja. Georadar se uporablja za zaznavanje praznin, strukturnih znacilnosti kamnin v kamnolomih, kraških vodonosnikih, pri gradbenih posegih v prostor in tudi v arheo­logiji. Temeljne raziskave, ki bi obravnavale kra­ška vprašanja, ki niso povezana z oceno tveganj in napovedovanj nevarnosti (ang. risk assessment, hazard), so redka. Vecina študij posredno obrav­nava kraški sistem, kjer so glavni cilj raziskav posledice zakrasevanja kamnin, ki lahko povzro-cijo škodo oz. tveganje za nevarnost (pogrezanje, udiranje) oz. ranljivost kraškega sistema (kraški vodonosniki). V nadaljevanju so po razlicnih aplikacijah predstavljene objavljene ali lastne raziskave ter podane prednosti in omejitve georadarske metode. Jame in praznine Najbolj pogosta uporaba georadarja na kra­škem površju je zaznavanje jam in praznin v po­vezavi z inženirsko-geotehnicnimi posegi v pros-tor in na obmocjih posedanj in ugrezanj. Prazen jamski prostor se navadno dobro odraža na ra­dargramih zaradi velikega kontrasta v dielek­tricni konstanti med kamnino in zrakom. Seveda je treba upoštevati, da so lahko praznine delo-ma ali popolnoma zapolnjene s sedimentom, kar nakazuje hitrost razširjanja EM valovanja, ki jo dobimo s prileganjem hiperbole. Georadar je primeren za zaznavanje jam do globine 30 m, seveda v odvisnosti od izbrane fre­kvence in terenskih pogojev. Pomembno je, da poznamo oz. predvidevamo globinski doseg pri doloceni frekvenci v danih pogojih na terenu ter vertikalno in horizontalno locljivost metode (tabela 1). Pri tem je pomembna predvsem ho- rizontalna locljivost georadarja, ki se z globino manjša, kar pomeni, da na vecjih globinah lah­ko zaznamo le vecje jame. Martínez-Moreno et al. (2013, 2014) so podali pregled raziskav z raz- licnimi geofizikalnimi metodami ter približno globino, kjer so zaznali jame. Globina detekcije podpovršinskih praznin v študijah, ki so vklju- cevale metodo georadarja, je znašala med 4–28 metri. Za raziskave globljih jam (40–80 m) se je izkazalo, da je primernejša uporaba razlicnih elektricnih metod v kombinaciji z magnetnimi in/ali gravimetricnimi metodami (Martínez-Mo­reno et al., 2013). Metoda georadarja za zaznava­ nje jam in manjših praznin je primerna vecinoma najvec do globine 30 m. Georadarske raziskave zaznavanja jam in manjših praznin ter doloca­nje geometrije in razširjanje praznih prostorov v podpovršju se najveckrat dopolnjujejo z ostalimi elektromagnetnimi in elektricnimi metodami (Brown et al., 2011; Carričre et al., 2013; El-Qady et al., 2005; Gmez-Ortiz & Martín-Crespo, 2012; Lazzari et al., 2010), redkeje z gravimetricnimi (Beres et al., 2001; Mochales et al., 2008; Leucci & De Giorgi, 2010) in seizmicnimi metodami (Car-darelli et al., 2010). V vecini naštetih raziskav je bil cilj zaznati jame in praznine, v nekaterih pa se je georadar uporabil tudi kot komplementarno metodo pri preucevanju nastanka jam in njihovih zapolnitev (Murphy et al., 2008). V arheoloških študijah so georadar uporabili tudi za zaznava­nje in lociranje jam v apnencih, znotraj katerih se lahko nahajajo sedimenti primerni za izkopava­nje (Chamberlain et al., 2000). V teoriji se jamski prostor na radargramih odraža kot hiperbolicni odboj. Takšen odboj do-bimo, ce je profil usmerjen precno na razširjanje jame in je ta v preseku polkrožne oblike. V pra­ksi se velikokrat izkaže, da so ti odboji komple­ksnejši, in zaradi nehomogenosti, kot so razlicne geološke plasti, strukturne znacilnosti (razpo­ke, prelomi), ne vedno tako ocitni. Na obliko in znacaj anomalije vpliva tudi velikost, oblika in globina jame, zapolnitev ter tudi terenski pogo-ji na površju. Poleg tega je potrebno upoštevati vse možne dejavnike, ki bi lahko na radargramih predstavljali motnjo oz. šum, npr. odboji od dre­ves, ograj in elektricnih napeljav. Lep primer anomalije nad jamo predstavlja radargram na sliki 9 posnet nad jamo Biserujko na otoku Krku. Vhodni del jame predstavlja veli­ka dvorana polkrožne oblike, kar se na radargra-mu jasno odraža z odbojem hiperbolicne oblike. V praksi je takšnih primerov malo, navadno so odboji od jam in praznin kompleksnejši. To pri­ kazuje slika 10, kjer sta prikazana dva profila nad vhodno dvorano Najdene jame pri Lazah na Planinskem polju. Na profilu 1, kjer smo meritev izvajali precno nad vhodno dvorano, se ta odra­ža z eno vecjo hiperbolo na globini 10 m (sl. 10a). Povsem drugacen radargram kaže profil 2, kjer smo merili v vzdolžni smeri nad vhodno dvora-no (sl. 10b). Celotna dolžina profila se nahaja nad jamsko dvorano, ki se odraža z manjšimi difrak­cijskimi hiperbolami po celotni dolžini. Te se na­hajajo na razlicnih globinah med 5 in 14 metri (rdece pušcice). Vhodna dvorana je zelo razgiba­ne oblike z jamskim stropom na razlicnih globi­nah, zato dobimo tako kompleksen radargram. Kljub temu, da je zaznavanje jam najbolj razširjenja in relativno enostavna uporaba ge­oradarja, je dobljen radargram lahko zelo kom­pleksen. Izdelava sinteticnih modelov in modeli­ranje je zato bistvenega pomena pri interpretaciji in inverziji georadarskih podatkov (Beres et al., 2001; Leucci & De Giorgi, 2010). Obmocja udorov in pogrezanj Na krasu zaradi procesov zakrasevanja v podpovršju prihaja do nenadnih porušitev, kar je lahko nevarno, še posebej v urbanih okoljih. Procesi, ki vodijo do nastanka udorov in pogre­zanj, so razlicni. Obstajajo številne genetske kla­sifikacije, kar pa presega namen tega prispevka. Sl. 9. Primer radargrama nad jamo Biserujko na Krku. Dvorana je velika in polkrožne oblike, zato izmerjeni precni profil nad jamo povzroci jasno hiperbolicno anomalijo. Fig. 9. Example of a radargram above the Biserujka cave on Krk. The hall is large and of a semi-circular shape, so the mea­sured transverse profile above the cave causes a clear hyperbolic anomaly. Sl. 10. Primer meritev nad Najdeno jamo, kjer je radargramski znacaj na dveh profilih razlicen glede na obliko jame in smer profila. Zaradi kompleksne oblike jame se ta odraža zelo razlicno, kot nepopolna hiperbola (profil 1, pravokotno na smer raz­širjanja vhodne dvorane) in vec manjših odbojev (profil 2, v smeri daljšega razširjanja vhodne dvorane). Omenila bi samo, da se izraz »doline« za vrtaco uporablja bolj v evropski literaturi, medtem ko se v Severni Ameriki ter v inženirsko-okoljskih raziskavah pogosteje uporablja izraz »sinkhole«, ki se nesistematicno uporablja tako za vrtace kot tudi udornice, za udornice in obmocja pogrezanj pa tudi »collapse sinkhole« in redkeje »collapse doline« (Carbonel et al., 2015; Gutiérrez et al., 2014). Na obmocjih, ki so podvržena procesom udi­ranja (ang. collapse) ali pogrezanja (ang. subsi­dence), je pomembno raziskati, kaj se dogaja v podpovršju, saj na površju pogosto ni vidnih zna­kov zakrasevanja. Ko se poruši ravnotežje, lahko pride do nenadnih udorov, ki lahko povzrocijo ogromno škode. Vecje obmocje takšnih pojavov predstavlja Florida in druga obmocja v ZDA kot so Teksas, Alabama in Pensilvanija. Drugi, poca­snejši proces, pogrezanje oz. posedanje, pa prav tako povzroca nestabilnosti, ki vplivajo na infra-strukturo urbanih obmocij. Poleg kraških pojavov v karbonatnih kamni­nah se podobni procesi odvijajo v evaporitnih kamninah kot je sadra, halit in anhidrit. Procesi zakrasevanja v evaporitnih kamninah so bistveno hitrejši od tistih v karbonatnih, zato so obmocja udorov in pogrezanj predmet številnih geofizi­kalnih raziskav. Procesi v evaporitnih kamninah se v marsikaterem pogledu precej razlikujejo od procesov v karbonatnih kamninah. Poleg hitrej­šega raztapljanja so takšne kamnine tudi mehan­sko manj odporne in stabilne ter bolj duktilnega znacaja. Georadarsko metodo so uporabili v šte­vilnih raziskavah vzdolž Mrtvega morja (Frum-kin et al., 2011; Ezersky et al., 2017; Ronen et al., 2019). V zadnjih 30 letih je bilo evidentiranih na stotine udorov vzdolž Mrtvega morja tako v Izra­elu kot v Jordaniji, pri cemer je prišlo do vec ne­srec na urbanih obmocjih (Frumkin et al., 2011). Jame oz. praznine na tem obmocju se pojavljajo vecinoma na globini 20–70 m in pod nivojem sla­ne podzemne vode, kar predstavlja glavni omejit­veni dejavnik za georadarsko metodo, zato so bile za detekcijo globljih jam uporabljene tudi druge geofizikalne metode. Integracija geofizikalnih metod z ostalimi geološkimi metodami je bistve-no izboljšala zaznavanje praznin in potencialnih obmocij za nastanek udora. Georadar se je izka­zal za najboljšo izbiro pri zaznavanju praznin v plitvem podpovršju do globine 15 m. Na sliki 11 je predstavljen takšen primer georadarskih me-ritev, kjer so z meritvami dolocili mesta poten­cialnih udorov (Ronen et al., 2019). Samo nekaj mesecev po meritvah je prišlo do udora. Odboji od praznin so vecinoma zelo kompleksni. Procese zakrasevanja v neogenskih evaporitih intenzivno preucujejo tudi na obmocju Zaragoze v Španiji (Rodriguez et al., 2014; Carbonel et al., 2015; Sevil et al., 2017). V Španiji izdanki evapo­ritnih kamnin (sadra, anhidrit, halit) neogenske, Sl. 11. Primer uporabe georadarja (šcitena 100 MHz antena) na obmocju udornic ob zahodni obali Mrtvega morja (iz Ronen et al., 2019 z dovoljenjem): a) zracni posnetek obmocja raziskav; b) shematski prikaz situacije trase profila 012; c) radargram linije 012, kjer obmocja mocnih refleksov (hiperbol) pripadajo jamam na globini med 9–13 m. Fig. 11. Example of the use of a georadar (shielded 100 MHz antenna) in the area of sinkholes along the western coast of the Dead Sea (from Ronen et al., 2019 with permission): a) an aerial view of the survey area; b) a schematic situation of the route of the profile 012; c) the radargram of line 012, where areas of strong reflections (hyperbola) belong to caves at depths between 9–13 m. paleogenske in triasne starosti predstavljajo oko­li 7 % površja (Gutiérrez et al., 2008). Zaradi hi-trega raztapljanja prihaja do hitrih sprememb na površju, ki so odraz vecinoma podzemnih pro-cesov zakrasevanja. Zaradi varnosti in visokih stroškov sanacij so ta obmocja v zadnjih 20 letih vkljucena v številne raziskave, da bi bolje razu­meli procese v evaporitnih kamninah, tok podze­ mne vode in nenazadnje, da bi preprecili tovrstne nesrece. V okviru geoloških, sedimentoloških in geomorfoloških raziskav sta bila georadar in elektricna upornostna tomografija velikokrat aplicirana. Rodriguez et al. (2014) so raziskali možnosti uporabe georadarja za karakterizacijo dveh depresij na pokritem krasu, ki sta nastali z razlicnima procesoma. Rezultati georadarskih meritev so tako omogocili zanesljivo dolocitev mej depresij, znacilnosti njihove notranje geome­trije z deformacijskimi znacilnostmi. Na podlagi pridobljenih podpovršinskih podatkov so lah­ko sklepali na mehanizem pogrezanja in ocenili magnitudo le-tega. Metoda je imela tudi nekate-re pomanjkljivosti. Zaradi prisotnosti glinenih in meljastih sedimentov znotraj vrtac je bil glo­binski doseg omejen, ponekod pa so nadpovršin- ski odboji (elektricna napeljava, zidovi, drevesa) povzrocili motnje na radargramih. V raziskavi so uporabili nešciteni 100 MHz in 50 MHz anteni ter 180 MHz šciteno anteno. Bistveno boljše rezul­tate so pridobili z nešciteno anteno. Na podlagi rezultatov nešcitene antene so naredili celovito rekonstrukcijo obmocij pogrezanja in dolocili naklon plasti. Na radargramih šcitene antene so zaznali le meje depresij. V okviru interdiscipli­ narnih raziskav rezultate geofizikalnih metod dopolnjujejo tudi z razkopi (Carbonel et al., 2014; 2015; Sevil et al., 2017). Integracija georadarja in elektricne upornostne tomografije (ERT) z razko-pi je prikazana na sliki 12. V zadnjih 15 letih so tovrstne raziskave poleg zaznavanja jam, ki so lahko povezane tudi z mes-ti udorov, najbolj razširjena uporaba georadarske metode. Študije, ki obravnavajo to problematiko so številne (Delle Rose & Leucci, 2010; Gmez-Or­tiz & Martín-Crespo, 2012; De Giorgi in Leucci, 2014; Bumpus in Kruse, 2014; Pueyo-Anchuela et al., 2015; Kaufmann et al., 2018), saj predvsem v urbanih obmocjih predstavljajo takšni pojavi eno Sl. 12. Dopolnjevanje geofizikalnih metod z razkopi in geokronološkimi metodami (iz Sevil et al., 2017 z dovoljenjem): a) in b) depresija jasno vidna na radargramu slike 100 MHz antene. Profil iz leta 2013 je bistveno boljše kvalitete kot isti izmerjen leta 2017, kar je verjetno posledica vecje vsebnosti vode v casu meritev leta 2017; c) rezultati razkopa; d) rezultati ERT, kjer obmocje pogrezanja ni vidno, je pa viden stik z maticno podlago. permission): a) and b) the sinkhole is clearly visible on the radargram of the 100 MHz antenna image. The 2013 profile is of significantly better quality than the one measured in 2017, which is probably due to the higher water content at the time of the 2017 measurements; c) results of the excavation; d) ERT results where the subsidence area is not visible but contact with the bedrock is evident. od najpogostejših oblik nevarnosti na kraškem površju zaradi cesar so takšne raziskave veli­kokrat interdisciplinarne in jih dopolnjujejo ne­ katere tudi dražje metode. S tega vidika tovrstne raziskave prinašajo informacije, ki so preverjene z razlicnimi metodami, kar prispeva k boljšemu poznavanju georadarja v razlicnih terenskih po­gojih, in imajo metodološki doprinos. Epikras in kontakt tla/maticna podlaga Georadar se pri raziskavah tal najveckrat uporablja za dolocevanje globine, lateralnega razširjanja in variabilnosti pedoloških hori­zontov, ki so znacilni za posamezne skupine tal (Doolittle, 1987; Puckett et al., 1990; Stroh et al., 2001). Georadar lahko zazna mejne horizonte, ki se dovolj razlikujejo v pedološko-mineraloških lastnostih, da meje na radargramih predstavljajo prepoznaven reflektor. Z georadarjem naceloma ne moremo zaznati majhnih sprememb v znacil­nostih tal, kot so barva, struktura in poroznost ter prehodnih pedoloških horizontov (AB, AC, BC) in zveznih sprememb znotraj posameznih horizontov (Doolittle & Butnor, 2009). Visoko amplitudne reflekse povzrocajo nena­dne spremembe na mejah med pedološkimi ho-rizonti, ki jih povzrocajo razlike v vsebnosti vla­ge, fizikalne razlike (spremembe v teksturi tal in gostoti) in/ali kemijske spremembe (prisotnost organskega materiala, kalcijevega karbonata in seskvioksidov). Eden izmed bolj znacilnih hori­zontov je argilicni horizont (Bt), ki vsebuje vecji delež glinenih mineralov in ima tudi vecjo gosto-to (Collins & Doolittle, 1987). Prav tako je jasna meja v spodicnih horizontih (Bh, Bfe) zaradi pri­sotnosti humusa in seskvioksidov, ki se kopicijo iz višje ležecih horizontov. Bt horizont smo zaznali na obmocju vrtac v konglomeratih, kjer so tla dobro razvita. Bt hori­zont je na obmocju pleistocenskih konglomeratov tudi precej debel. Na podlagi oblike Bt horizonta glede na današnjo morfologijo antropogeno spre­menjenih vrtac smo z georadarskimi meritvami pridobili informacije o obliki in globini vrtac preden so bile te obdelane (Ceru et al., 2017). Z georadarjem naceloma lahko zaznamo tudi mejo med sedimentom in maticno podlago, ce je meja nenadna in dovolj kontrastna. Navadno je ta meja prepoznavna kot visoko-amplitudni reflek-tor, ki je zvezen. Kljub vsemu pa velikokrat meja med nevezanim sedimentom in maticno podlago ni jasna in je z georadarjem ne moremo zaznati, ce prehod ni oster in raven, in ce je zanj znacil-no, da se na meji pojavljajo vecji kosi preperele maticne podlage (Doolittle & Butnor, 2009). To je znacilno za kraški sistem, kjer je meja med se­dimentom in maticno podlago neravna s pojavi kraških žepov in zveznim prehodom tal v prepe­relo maticno podlago. V takšnih okolišcinah se je izkazalo, da meje med sedimentom in karbonat- no podlago z georadarjem vecinoma ne moremo zaznati. V zacetkih uporabe georadarja na krasu je bilo objavljenih nekaj raziskav, kjer so doloceva­li mejo med tlemi in karbonatno podlago, med-tem ko se je v zadnjih 20 letih število tovrstnih raziskav bistveno zmanjšalo. Doolittle & Collins (1998) sta uporabila EM indukcijo in georadar na krasu na dveh razlicnih lokacijah, Floridi in Pensilvaniji. Ugotovila sta, da imata obe meto­di svoje pomanjkljivosti glede na lastnosti tal in specifike preucevanega terena. Interpretacija zaradi slabega globinskega dosega in locljivosti ter premajhnega kontrasta v elektricnih lastno­stih razlicnih materialov ni bila vedno jasna. Z uporabo 120 MHz antene so bile meritve na tleh v Pensilvaniji neuspešne, saj je bilo dušenje si­gnala zaradi prisotnosti argilicnega horizonta preveliko, da bi lahko zaznali mejo med tlemi in karbonatno podlago. Metoda EM indukcije pa je v primeru bolj prevodnih tal dala boljše rezulta­te. Georadar je bil uspešnejši pri dolocevanju mej med peskom in apnencem ter med peskom, glino in zakraselim apnencem (Collins et al., 1990). V Sloveniji karbonatne kamnine in depresi­je prekrivajo tla s precejšnjim deležem glinene komponente, zato je meja med tlemi in maticno podlago težje dolocljiva. Prav tako tudi debeline in kontakta med zapolnitvijo in maticno podlago v kraških depresijah na razlicnih obmocjih raz­iskav v Sloveniji vecinoma nismo zaznali. Debe­lina sedimentov je bila prevelika oz. so lastnosti sedimentov onemogocale vecji globinski doseg. V primeru raziskav vrtac v konglomeratih smo kontakt dolocili posredno. Takšen primer raziskav je predstavljajo obmocje vrtac v najmlajšem kon­glomeratnem zasipu (Podbrezje), kjer smo kontakt dolocili na podlagi pojavljanja hiperbol, ki naka­zujejo praznine oz. heterogenosti v konglomeratu. V dnu vrtace je na terenu vidna manjša poglobi­tev, kar se s pojavi veckratnih hiperbolicnih od­bojev (moder pravokotnik na sliki 13) odraža tudi na radargramu. Nekatere vrtace v konglomera­tih so nastale s sufozijskimi procesi, pri katerih se nesprijet material spira skozi razpoke v spodaj ležec zakrasel konglomerat, zato so na površju po­nekod vidni grezi ali manjše poglobitve. Poleg tipicnih kraških pojavov se je georadar izkazal kot primerna metoda tudi za karakte­ rizacijo pokritega krasa in dolocitev meje med Sl. 13. Na podlagi pojavljanja hiperbolicnih anomalij (modra barva) smo dolocili približno mejo med tlemi in konglomeratom (rdeca crtkana linija). Fig. 13. The contact between soil and conglomerate bedrock (red dashed line) was defined by occurrences of hyperbolic diffra­ctions (blue colour) related to the heterogeneities in conglomerate. epikraško cono in kompaktnejšim apnencem pod njo (Tallini et al., 2006). V raziskavi so uporabili 40 MHz nešciteno in 100 MHz nešciteno anteno. Globinski doseg je v danih pogojih znašal 12 m (40 MHz) oz. 4 m (100 MHz), zato je bila vecina meritev izvedenih s 40 MHz anteno. Tovrstne študije so zelo redke. Kraški vodonosniki Zelo pomembne so tudi raziskave kraških vodonosnikov, ki pogosto predstavljajo zelo ranljiva obmocja zajetij pitne vode. Georadar predstavlja komplementarno metodo za bolj­še razumevanje hidrodinamicnega mehanizma strukturno heterogenega kraškega hidrosiste-ma, kjer na podlagi lociranja prelomov, kraških kanalov, votlin in ostalih kraških znacilnosti lahko lažje karakteriziramo in konceptualizira-mo strukturo vodonosnika. Pri raziskavah kra­ških vodonosnikov je navadno glavni cilj locirati razpoklinske cone in kanale, prelome in jame ter dolociti geometrijo vseh teh elementov v prosto­ru in podatke iz vrtin dopolniti z georadarski-mi rezultati (Al-Fares et al., 2002). Cunningham (2004) je na podlagi rezultatov študije ugotovil, da obstaja empiricna povezava med izmerjenimi parametri iz vrtin (poroznost, hidravlicna pre­vodnost) in poroznostjo pridobljeno iz slik karo­tažnih meritev v vrtinah ter amplitude signala georadarskih podatkov. Ugotovil je, da se ampli­tuda radarskega signala zmanjšuje z vecanjem poroznosti in hidravlicne prevodnosti dolocene s podatki iz vrtin, kar omogoca kvalitativno oce­njevanje vertikalne in horizontalne porazdelitve poroznosti in hidravlicne prevodnosti. Carričre et al. (2013) so kombinirali georadar in ERT za karakterizacijo kraških kamnin in z namenom bolje razumeti prenos vode znotraj nezasicene cone vodonosnika in skladišcenja vode. Z in-tegracijo dopolnjujocih metod in poznavanjem geologije tega obmocja so uspeli podrobneje ka­rakterizirati kamnine preucevanega obmocja (sl. 14). Kombinacijo ERT metode in georadarja so uporabili tudi v raziskavi vodonosnika v Kanadi (Martel et al., 2018). Izvedena je bila multidisci­plinarna študija za boljše poznavanje podzemne dinamike toka in jamskih poti. Geofizikalne me-tode so dopolnilni s sledilnimi poskusi in vrti­nami ter radarsko interferometrijo (InSAR) za detekcijo premikov na stavbah na obmocjih za­polnjene depresije. Mount et al. (2014) so georadar uporabili za dolocitev porazdelitve poroznosti v vodonosni­ku in dolocitev lateralnega razširjanja kraških struktur. Na podlagi porazdelitve difrakcijskih hiperbol na radargramih so dolocili spremembe v hitrosti elektromagnetnega valovanja in iz tega je bila izracunana poroznost z uporabo petrofizi­kalnega modela CRIM (ang. complex refractive index model). Iz opisanih in prikazanih primerov je za na-men hidrogeoloških raziskav nujen multidisci­plinaren pristop, ki poleg geofizikalnih metod zajema tudi hidrogeološke in druge metode. Kamnolomi V kamnolomih karbonatnih in evaporitnih ka­mnin procesi zakrasevanja, ki vodijo do nastanka jam, kraških kanalov in udorov, povzrocajo šte­vilne težave pri eksploataciji mineralne surovine. Pogoji za georadarske meritve v odprtih površin­skih kamnolomih so pogosto dobri, saj je površina ravna, preperinskega sloja, ki bi oviral prodira­nje EM valovanja v globino ni. Poleg tega lahko rezultate georadarskih meritev vzporejamo z de­tajlnim geološko-strukturnim kartiranjem in ve­ Sl. 14. Primer integracije rezultatov georadarja in elektricne upornostne tomografije (Carričre et al., 2013 z dovoljenjem). Podatki obeh metod so skladni, hkrati pa se dobro dopolnjujejo, pri cemer georadar poda podrobnejše informacije o strukturi plitvejšega podpovršja. Medtem ko je globinski doseg georadarja znašal do 12 m oz. na obmocjih, kjer je bil prisoten glinen material, celo samo dva metra, so rezultati ERT dopolnili podatke v globino. structure of the shallower subsoil. While the depth of the georadar measurements was up to 12 m, or even just 2 metres in areas where clayey material was present, the ERT results completed the georadar data in greater depths. likokrat tudi s podatki iz vrtin. Georadarska me- toda se uporablja pri razlicnih fazah pridobivanja kamna. Lahko se uporablja v zacetnih fazah pri splošni oceni kvalitete kamnoloma oz. bodocega nahajališca mineralnih surovin ali pri podrob­nejših preiskavah, pri nacrtovanju eksploatacij­skega materiala, kjer je pomembno natancno do-lociti smeri prelomnih struktur, razpok in jam. Za karakterizacijo strukturno-geoloških in hidrogeoloških znacilnosti pri nacrtovanju ek­sploatacijskih dejavnosti v kamnolomih se je geo-radar izkazal za zelo uporabno metodo v številnih študijah. Grandjean & Gourry (1996) sta uporabi-la georadar za zaznavanje in kartiranje razpok ter drugih kraških struktur v kamnolomu marmorja. Z uporabo 300 in 900 MHz antene so pridobili in-formacije do globine 15 oz. 8 m in naredili model razpok. Grasmueck et al. (2013) so uporabili 100 in 200 MHz anteni za raziskavo sub-vertikalnih razpok in jam v zapušcenem kamnolomu kredne­ga apnenca. Z gosto mrežo vzporednih meritev in z ustreznimi naprednimi postopki obdelave (3D migracija podatkov) so naredili 3D model poteka vseh razpoklinskih con in dolocili glavne smeri prevladujocih razpok. V Sloveniji je bil georadar uporabljen v kamnolomu Rodež za zaznavanje kraških pojavov (Zajc et al., 2014). V kamnolomih se lahko uporablja tako šciten kot tudi nešciten sistem anten. Pri nešciteni an- teni lahko prihaja do odboja od stene kamnolo- ma, zato meritve izvajamo po sredini etaže. Pri podzemnem pridobivanju kamna lahko težave povzrocajo odboji od sten in stropa, seveda v od­visnosti od velikosti podzemnega pridobivalne­ga prostora. Meritve v Lipiškem kamnolomu so pokazale, da so nekateri radargrami zaradi nad­površinskih odbojev popolnoma neuporabni, pri cemer se izkaže, da so šcitene antene primernejše (sl. 15). Na obmocjih, kjer so bile stene kamnolo-ma dovolj oddaljene, dobimo na radargramih le horizontalen odboj od stropa. Brezstrope jame in jamski sedimenti Poleg omenjenih aplikacij, ki so bolj ali manj uveljavljene v georadarski stroki, v tem poglavju podajam novo uporabo georadarja. Ker so brez­strope jame oz. posamezni segmenti brezstropih jam pomemben del današnje morfologije terena, je pomembno njihovo prepoznavanje na površju. Dokazi za obstoj brezstropih jam (jamska siga, jamski sedimenti…) velikokrat niso prisotni oz. so nerazpoznavni, zato je pomembno, da lahko z geofizikalnimi metodami dokažemo speleogenet-ski nastanek kraških oblik. Obmocje obsežnejših študij brezstropih jam je bil otok Krk (Ceru et al., 2018a), jamskih sedi­mentov pa severni rob Planinskega polja (Ceru et al., 2018b). Obmocji sta bili izbrani zaradi za­ Sl. 15. Primer meritev v podzemnem pridobivalnem prostoru kamnoloma Lipica II. Pri 50 MHz nešciteni anteni nadpovršinski odboji od sten in stropa kamnoloma popolnoma prekrijejo odboje iz globine. Meritev s šciteno 250 MHz anteno razkrije manjše praznine in diskontinuitete znotraj apnenca. completely cover the GPR information with a 50 MHz unshielded antenna. Measurement with a 250 MHz shielded antenna reveals smaller voids and discontinuities within the limestone. nimivega geološkega in geomorfološkega razvoja ter zaradi raznovrstnosti kraških oblik. Rezul­tati obeh študij predstavljajo novo uspešno upo­rabo georadarja v temeljni krasoslovni znanosti. Georadar se je izkazal za zelo uporabno metodo pri karakterizaciji brezstropih jam in pri pro-storskih spremembah v znacilnostih tal v pri­meru zaznavanja jamskih sedimentov. Ceprav se brezstrope jame na obeh obmocjih površinsko odražajo zelo razlicno, smo z razlicnim interdi­sciplinarnim pristopom, kjer je georadar pred­stavljal kljucno metodo, uspeli pridobiti ustre­zne podatke za njihovo lažjo rekonstrukcijo. Na obmocju planote med Vrbnikom in Staro Baško smo z georadarskimi raziskavami dolocili mesta povezav med razlicnimi oblikami. Za ta je znacilna vecja debelina sedimentov, kar se na radargramih odraža z vecjim dušenjem signala. Poleg tega smo našli vec podzemnih nadaljevanj oz. podzemnih delov sicer vecinoma denudira­nega jamskega sistema. Definirali smo prehodno obmocje med površinskim in podpovršinskim delom brezstrope jame. Za ta obmocja so zna-cilne manjše praznine, zato smo jih opredelili kot porušne oz. prehodne cone. S pomocjo geo­radarskih meritev in terenskega ter geomorfolo­škega pregleda na podlagi podatkov daljinskega zaznavanja smo opredelili 4 km dolg brezstrop jamski sistem. Na obmocju severnega in vzhodnega obrob­ja Planinskega polja smo izvedli testne meritve za zaznavanje jamskih sedimentov. Želeli smo raziskati, kako zanesljivo lahko z georadarjem zaznamo jamske sedimente. Na obmocjih, kjer se jamski sedimenti pojavljajo skupaj z jamsko sigo, so meritve pokazale, da se ti jasno odraža­jo na radargramih z izrazitim dušenjem signala. Meritve smo nato izvedli tudi na širšem obmo- cju, kjer smo dolocili mesta jamskih sedimentov in njihovo razširjanje v prostoru (sl. 16). Da bi preverili zanesljivost metode in ugotovili, kateri dejavnik najbolj prispeva k dušenju signala, smo preucevali mineraloško-geokemicne znacilnosti jamskih sedimentov in tal. Raziskave so poka­ zale, da jamski sedimenti vsebujejo vecji delež glinenih mineralov in Fe/Al oksidov in hidroksi­dov v primerjavi s tlemi na karbonatnih tleh. Na podlagi tega smo sklepali, da je poleg debeline sedimentov kljucni dejavnik za povecano duše­nje tudi drugacen delež posameznih mineralov. Poleg tega prisotnost Fe/Al oksidov in hidroksi­ dov vpliva k vecjemu zadrževanju vode, kar razloži tudi dejstvo, da se na obmocjih jamskih sedimentov voda zadržuje tudi cez daljša sušna obdobja. Diskusija in zakljucki V prispevku smo podali pregled uporabe geo­radarja na krasu. Bistvena prednost georadarja je dobra locljivost, ki omogoca natancen vpogled v podpovršje, zato predstavlja najbolj ustrezno geofizikalno metodo pri raziskavah, kjer nas za­nimajo informacije do globine 30 m. Vecina ge­oradarskih raziskav krasa je osredotocenih na najbolj široko uveljavljene aplikacije kot je za­znavanje jam, raziskave kraških vodonosnikov in raziskave strukturnih lastnostih kamnin po­vezanih s procesi zakrasevanja. V zadnjih 20 le­tih so raziskave predvsem aplikativnega znacaja in metoda se v integraciji z ostalimi uporablja pri Sl. 16. Meritve jamskih sedimentov na obmocju severnega roba Planinskega polja z 50 in 250 MHz anteno (Ceru et al., 2018b): a) smer pravokotnih profilov 2a in 2b na obmocju jamskih sedimentov; b) na podlagi georadarskih rezultatov je bil dolocen obseg jamskih sedimentov tudi tam, kjer ti niso vidni na površju; c) obmocje jamskih sedimentov na radargramih sovpada z obmocjem na površju. GPR are limited to the area of the outcrop visible on the surface. preprecevanju nevarnosti pogojenih z zakraseva­njem. Zelo redke so temeljne raziskave, ki bi pre-ucevale osnovna krasoslovna vprašanja. V clan-ku smo predstavili pestrost uporabe metode in naredili kratek pregled po razlicnih aplikacijah, med katerimi smo izpostavili tudi nove aplikaci­je kot je zaznavanje brezstropih jam in jamskih sedimentov. Kraško površje je vecinoma težko prehodno in razgibano, kar predstavlja mocno oviro za marsi­katero geofizikalno metodo, a uporabljen sistem s 50 MHz RTA anteno omogoca meritve tudi na takšnih terenih. Omenjena antena se je izkazala za najbolj primerno za vecino kraških aplikacij, pri cemer sta glavni prednosti primeren globin-ski doseg in lažje manevriranje z RTA anteno v primerjavi s šciteno 250 MHz anteno. Vecina objavljenih raziskav je interdiscipli­narnega znacaja, kjer se rezultati geofizikalnih metod dopolnjujejo z geološkimi, hidrogeološki-mi in geomorfološkimi metodami. Uporabnost metode je zelo odvisna od lastnosti terena in kra­škega sistema. Enoznacna navodila za izvajanje georadarskih meritev na krasu niso smiselna, saj je uspešnost uporabe metode odvisna od šte­vilnih dejavnikov. Na obmocjih, kjer so prisotni sedimenti z vecjih deležem glinenih mineralov, je dušenje signala mocno, zato je globinski do-seg lahko samo nekaj metrov ali manj. Po drugi strani, pa ravno ta lastnost metode omogoca, da Tabela 4. Prednosti in nekatere omejitve georadarja pri razlicnih aplikacijah na krasu. (+ primerna, ± lahko pogojno uporabna z nekaterimi omejitvami, – ni primerna). Table 4. Advantages and some limitations for different applications of GPR in karst. (+ appropriate, ± may be used, but not necessarily the most appropriate method, – not recommended). Uporaba (Application) Možnost uporabe (Possibility of use) Prakticni nasveti, omejitve (Practical guides, limitations) Debelina kraških tal–stik z maticno karbonatno podlago Thickness of karst soil - contact with the carbon­ate bedrock Debelina kraških tal–stik s konglomeratno podlago Thickness of karst soil - contact with the con­glomerate bedrock –/ ± ± - neenakomeren prehod med tlemi in maticno podlago (neraven kontakt z vmesnimi žepi) - meja med tlemi in podlago vecinoma ni nenadna, zato kontakt ne predstavlja dobrega reflektorja - rezultate priporocljivo korelirati z razkopi, cestnimi useki - uneven transition between soils and bedrock (rough contact with cutters) - the boundary between the soil and the bedrock is rarely sudden, so the contact does not represent a good reflector - it is advisable to correlate the results with excavations, road cuts - meritve uspešne le v konglomeratnem zasipu najmlajše starosti, saj debelina tal ni prevelika - mejo med tlemi in konglomeratom smo dolocili na podlagi pojavljanja hiperbol zaradi nehomogenosti znotraj konglomerata - measurements are only successful in the youngest conglomerate fill, since the soil is not too thick - the boundary between the soil and the conglomerate was determined based on the occurrence of hyperbolas as a result of inhomogeneity within the conglomerate Zaznavanje jam in praznin Cave and cavity detection + - metoda primerna ob uporabi primerne antene glede na globinski doseg in locljivost metode - znacaj anomalije v najvecji meri odvisen od oblike jame in smeri profila glede na geometrijo jame - odboji od kompleksnejših jam so lahko zelo »netipicni« - method appropriate when using the appropriate antenna with respect to the depth range and resolution of the method - the character of the anomaly depends largely on the shape of the cave and the direction of the profile with respect to the cave geometry - reflections from more complex caves can be very “atypical” Oblika dna vrtac in debelina sedimentov - mocno dušenje signala zaradi prisotnosti sedimentov, ki vsebujejo precejšen delež znotraj vrtac –/± glinene komponente The shape of the bottom - strong attenuation of the signal due to the presence of sediments containing a of dolines and the thick- significant proportion of a clay component ness of sediments Raziskave brezstropih jam Unroofed cave research + - primerna za zaznavanje povezav med denudiranimi deli brezstropih jam - primerna za zaznavanje podzemnega nadaljevanja brezstropih jam - možno raziskovanje prehodnega obmocja med denudiranim in podzemnim delom jamskega sistema - suitable for finding links between segments of unroofed caves - suitable for detecting underground continuation of unroofed caves - it is possible to explore the transition of the transition area between the denuded and the underground parts of the cave system Jamski sedimenti Cave sediments + - metoda primerna, je pa potrebna pazljivost, da obmocij jamskih sedimentov ne zamenjamo z drugimi vecjimi debelinami sedimentov – npr. zapolnjena brezna itd. - the method is appropriate, but care must be taken not to confuse the cave sediment areas with other larger sediment thicknesses, e.g. filled shafts, etc. Pedološki horizonti Pedological horizons + - metoda primerna pri horizontih, ki se mocno razlikujejo v dielektricnih lastnostih npr. Bt horizont - metoda primerna na tleh, kjer so horizonti dobro razviti (primer tal na karbonatnih konglomeratih) - suitable for horizons that differ greatly in dielectric properties, e.g. Bt horizon - suitable in soils where horizons are well developed (for example soils on carbonate conglomerates) Jame in vrtace v konglomeratih Caves and dolines in conglomerates ± - velika debelina razvitih tal na konglomeratnih terasah starejšega in srednjega zasipa lahko predstavlja omejitev - metoda primernejša na najmlajših konglomeratnih zasipih, kjer debelina tal ne presega 3 m - excessive thickness of developed soil on the conglomerate terraces of the older and middle reaches - the method is more suitable on the youngest conglomerate backfill where the soil thickness does not exceed 3 m je primerna recimo za zaznavanje jamskih sedi­ mentov, saj se ti na radargramih jasno odražajo kot obmocja vecjega dušenja. Zaradi heteroge­nosti kraškega sistema so pogoji na terenu lahko zelo razlicni, zato v tabeli 4 podajam le nekatere usmeritve po aplikacijah. Podane so tudi neka­tere aplikacije, ki v svetu še niso široko uveljav­ljene. Tekom raziskav se je izkazalo, da je geora­dar za nekatere aplikacije bolj za nekatere manj uporaben, zato podajamo tudi nekatere omejitve, na katere smo naleteli pri razlicnih raziskavah. Z geofizikalnega vidika je kras s svojo he-terogenostjo zelo kompleksen sistem, ki ima za uporabo georadarja dolocene omejitve, ki jih moramo upoštevati pri nacrtovanju raziskav in interpretaciji podatkov. Zaradi heterogenosti sistema, v katerem se pojavljajo razlicne kraške oblike, kot so depresije in praznine, ki so lah­ko zapolnjene z zrakom ali/in sedimentom, lah­ko vcasih le z rezultati razlicnih geofizikalnih metod pridobimo glavne informacije o strukturi podpovršja. Interdisciplinarnost raziskav je kl-jucnega pomena, zato je za koncno interpretaci­jo georadarske meritve potrebno dopolnjevati z geološkimi, hidrogeološkimi in geomorfološkimi metodami. Uporaba le ene geofizikalne metode lahko vodi do napacnih interpretacij, sploh v bolj kompleksnih sistemih, kjer lahko geofizi­kalnim podatkom ustreza vec razlicnih modelov. Z razvojem tehnologije, boljšim poznavanjem teoreticnega ozadja metodologij in na podlagi prakticnih izkušenj raziskovalcev v zadnjih 15 letih, ima uporaba georadarja vse vecji poten­cial pri razlicnih vprašanjih na krasu. Zaenkrat je vecina georadarskih raziskav aplikativnega znacaja, ki pa so velikokrat zasnovana tako, da je cilj študije tudi razumevanje kraških proce­sov, ki vodijo do nastanka razlicnih kraških ob-lik. Na ta nacin imamo cedalje vec informacij in tudi znanja o kraškem podpovršju. 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CC Atribution 4.0 License https://doi.org/10.5474/geologija.2019.015 Razširjenost pesticidov v vodonosniku Dravskega polja Occurence of pesticides in Dravsko polje aquifer Anja KOROŠA & Nina MALI Geološki zavod Slovenije, Dimiceva ulica 14, SI – 1000 Ljubljana, Slovenija; e-mail: anja.korosa@geo-zs.si; nina.mali@geo-zs.si Prejeto / Received 16. 10. 2019; Sprejeto / Accepted 18. 12. 2019; Objavljeno na spletu / Published online 24. 12. 2019 Kljucne besede: podzemna voda, vodonosnik Dravsko polje, pesticidi Key words: groundwater, aquifer Dravsko polje, pesticides Izvlecek V clanku predstavljamo rezultate raziskave pojavnosti in koncentracij pesticidov v podzemni vodi Dravskega polja v obdobju 2013-2015. Na podlagi rezultatov smo ocenili prostorsko razširjenost pesticidov v podzemni vodi in jo povezali z rabo prostora. V obdobju dveh let smo odvzeli 76 vzorcev podzemne vode na 19 razlicnih lokacijah. V podzemni vodi smo dolocili 15 pesticidov z njihovimi metaboliti. Najpogosteje dolocen pesticid v podzemni vodi je še vedno atrazin in njegov razgradni produkt desetilatrazin. Sledijo mu metolaklor, terbutilazin in njegov razgradni produkt desetilterbutilazin. Pesticidi alaklor, dimetenamid, metazaklor in terbutrin niso bili doloceni. Analiza zaznanih pesticidov z rabo prostora kaže na višje vrednosti na obmocjih z intenzivno kmetijsko dejavnostjo. V severnem delu Dravskega polja, južnem robu mesta Maribor, so koncentracije pesticidov manjše, povišane vrednosti pesticidov pa se pojavljajo v južnem delu Dravskega polja, kar sovpada tudi z intenzivnejšo kmetijsko rabo tal na tem obmocju. Z vrednotenjem razmerij med razgradnim produktom in primarnim pesticidom iz naslova atrazina in terbutilazina (DAR in DTA/TBA) smo ocenili »starosti« onesnaženja. Presenetljiva je visoka pojavnost atrazina, ki je lahko posledica starih bremen, pocasne razgradnje in hidrogeoloških pogojev ali pa uporabe atrazina po uveljavitvi prepovedi uporabe. Abstract The article presents the results of a research on the occurrence and concentration of pesticides in the groundwater of the Dravsko polje aquifer in the period from 2013 to 2015. Based on the results, the evaluation of spatial distribution of pesticides in groundwater and the relation to land use was performed. In different hydrogeological periods, 76 groundwater samples were collected at 19 different locations. 15 pesticides with their metabolites in groundwater were identified. Despite the prohibition of use, atrazine and its degradation product desethylatrazine still remain the most commonly detected pesticides in groundwater. They are followed by metolachlor, desethylterbutylazine and terbutylazine. The pesticides alachlor, dimetamide, metazachlor and terbutrin were not detected. The analysis of detected pesticides by land use indicates higher values in areas with intensive agricultural activity. In the northern part of the Dravsko polje, where the city of Maribor is located, pesticide concentrations are lower. Increased pesticide values occur in the southern part of the Dravsko polje, which coincides with more intensive agricultural land use of the area. The coefficient of degradation product / primary pesticide ratio (DAR and DTA/ TBA) was used to estimate the "age" of contamination from atrazine and terbutilazine. Surprising is the high incidence of atrazine, which may result from old burdens, slow decomposition and hydrogeological conditions, or the use of atrazine after the enactment of the ban. Uvod Pesticidi so snovi, ki se predvsem v kmetij­stvu, pa tudi v gospodinjstvu, uporabljajo za zatiranje škodljivcev, plevelov in rastlinskih bo­lezni (Koroša & Mali, 2012). Uporabljajo jih tudi v gozdarstvu, lesarstvu, ladjedelništvu, itd. Po svojem nastanku so lahko naravne snovi, izoli­rane iz rastlin, ali sinteticno pridobljene s sinte­zo. Po svoji naravi so te spojine biološko aktiv­ne, nekatere so celo strupene. V podzemni vodi se pojavljajo tako primarne spojine, kot njihovi produkti razpadanja. Raziskave v Veliki Brita-niji so pokazale, da so v podzemni vodi odkrili višje koncentracije produktov razgradnje (meta­bolitov) v primerjavi s koncentracijami maticnih spojin (Kolpin et al., 2004; Lapworth & Gooddy, 2006). V okolje najpogosteje pridejo zaradi upora-be v kmetijstvu. Pesticide razdelimo na šest skupin: fungici­de (kaptan, benomil, triadimefon, folpet, man-kozeb), insekticide (DDT, metidation, metomil, lindan, heptaklor), herbicide (atrazin, alaklor, si­mazin, propazin, metolaklor, terbutilazin), aka-ricide (dikofol, propargit, klorfentazin), roden­ticide (endrin, varfarin, cinkfosfid) in limacide (metaldehid, metiokarb) (Yadav & Devi, 2017). Onesnaženje podzemne vode s pesticidi je sve­tovni problem. Ostanke pesticidov najdemo v vo­donosnikih širom po svetu (Ĺkesson et al., 2013; Kolpin et al., 1998). Gre za kompleksno proble­matiko zaradi razširjene uporabe pesticidov pri predelavi hrane in zaradi njihove širitve in aku­mulacije v okolju (Tadeo, 2008). Globalna pro-dukcija in uporaba pesticidov s casom narašca (Bernhardt et al., 2017; Sjerps et al., 2017). Pe­sticidni pripravki lahko vsebujejo eno ali vec ak­tivnih snovi, ki lahko z izpiranjem iz kmetijskih površin prehaja v površinsko in podzemno vodo (González-Rodríguez et al., 2011; Heuvelink et al., 2010; van Eerdt et al., 2014). Te emisije lahko predstavljajo tveganje za ekosisteme ali zdravje ljudi (Kim et al., 2017; Munz et al., 2017; Nien­stedt et al., 2012; Shelton et al., 2014; Stehle and Schulz, 2015). Seznami dovoljenih aktivnih snovi za uporabo se spreminjajo. Na podlagi novih spoznanj je mo­goce dolocene aktivne snovi prepovedati, lahko pa se prepoznajo nove, kot možne nadomestne snovi, ki so dovoljene (Sjerps et al., 2017). V Evropi so pe­sticidi regulirani in dovoljeni v skladu z Uredbo o fitofarmacevtskih sredstvih 1107/2009. Standard Evropske unije za pitno vodo iz Evropske direk­tive o pitni vodi (Uradni list EU, št. 98/83/ES) in standard kakovosti vode za telesa podzemne vode po direktivi o podzemni vodi (Direktiva 2006/118/ ES) dolocata najvišjo koncentracijo posameznega pesticida na 0,1 µg/l in vsoto merjenih pesticidov na 0,5 µg/l. Za oceno stanja oz. obremenitev pod-zemne vode so pomembne tako primarne spojine, kot tudi njihovi razgradni produkti. Porocanja o obsegu onesnaženja podzemne vode s pesticidi so v svetu zelo razlicna in so odvisna od osvešcenosti ljudi, stopnje raziska­nosti, kvalitete monitoringov ter nacina in in-tenzivnosti uporabe pesticidov (McManus et al., 2017). Na obmocju Dravskega polja so že v osem­desetih letih prejšnjega stoletja zaznali zelo visoke vrednosti pesticidov v podzemni vodi. Študije v letih 1982-1989 so pokazale, da so bile razmere na Dravskem polju glede onesnaženosti s pesticidi izjemno slabe (Brumen et al., 1990). Zanemarjanje prvih signalov je ob specificnih razmerah privedlo do izrazitega povišanja kon­centracij pesticidov v podzemni vodi, predvsem zaradi gramoznic, kjer so bili odloženi tudi os­tanki pesticidov (Brumen et al., 1990). Izredno povecanje koncentracije pesticidov na crpališcih v zacetku poletja 1989 je pripeljalo do zaprtja treh vecjih vodovodov. Sprejet je bil republiški interventni zakon za izvedbo oskrbe s kvalite­tno pitno vodo in za sanacijo podzemne vode na Dravskem polju. Nekatere zasute gramoznice so bile tudi sanirane (Knez & Regent, 1993; Fliser et al., 1991). Na obmocju Dravskega polja je uporaba pe­sticidov regulirana med drugim tudi z Uredbo o vodovarstvenem obmocju za vodno telo vodo­nosnikov Dravsko-ptujskega polja (Uradni list RS, 2007). Uredba prepoveduje uporabo fitofar­macevtskih sredstev za zatiranje škodljivih or- ganizmov na kmetijskih zemljišcih na najožjih vodovarstvenih obmocjih. Kakovost podzemne vode na Dravskem polju se kontrolira v okviru državnega monitoringa voda. Kemijsko stanje vodonosnika glede na pesticide je bilo v l. 2000 slabo. V obdobju 1993-2000 so bile presežene mejne vrednosti (Uradni list RS, 2002) za meto­laklor, atrazin, njegova razgradna produkta de­setilatrazin in desizopropilatrazin, prometrin in vsota pesticidov, ceprav so bili že opazni trendi padanja koncentracij (ARSO, 2004). Tudi v ob-dobju 2012-2018 je bilo kemijsko stanje podzemne vode za telo podzemne vode Dravska kotlina, kateremu pripada vodonosnik Dravskega polja, prepoznano kot slabo. Ceprav nekatere vrednosti pesticidov presegajo standarde kakovosti, pa dol­ gorocno trendi vsebnosti pesticidov padajo, tudi najbolj kriticnih kot sta atrazin in desetilatrazin (ARSO, 2019). Glede na pretekle velike obremenitve podzemne vode s pesticidi, je bil namen raziskave preveriti trenutno stanje prisotnosti pesticidov v podzem­ni vodi aluvialnega vodonosnika Dravskega po­ lja. V clanku predstavljamo rezultate raziskave v obdobju 2013-2015. Cilji raziskave so bili (1) ugotoviti stanje prisotnost izbranih pesticidov in njihove koncentracije, (2) oceniti njihovo prostor­sko razširjenost ter (3) povezati rabo prostora z njihovo prisotnostjo v podzemni vodi. Obmocje raziskav Dravsko polje leži v severovzhodnem delu Slovenije in pripada telesu podzemne vode »Dra­vska kotlina (3012)« (Uradni list RS, 2005). Dra­vsko polje predstavlja ravnino med Slovenskimi goricami, Pohorjem, Dravinjskimi goricami in Halozami. Na vzhodu se nadaljuje v Ptujsko po­lje. Obmocje Dravskega polja pokriva 293,2 km2. Hidrološka mreža je v osrednjem delu redka in ni razvejana, ob robu ravnine pa je gostejša (Urbanc et al., 2014). Najvišji predeli Dravskega polja le­žijo ob vznožju Pohorja (290 m n.m.v), najnižji pa pri sotocju Drave in Dravinje v jugozahodnem delu (207 m n.m.v) (Petauer, 1980). Glavni vodo­tok je reka Drava, ki tece v smeri severozahod--jugovzhod. Manjši vodotoki in potoki so Dravi­nja, Polskava, Kamenišcica, Reka, Trojšnica in Devina. Recni režim Drave je izrazito fluviogla­cialen, za katerega je znacilno, da ima najvišje povprecne mesecne pretoke maja in junija, naj­nižje pa januarja in februarja. Ostali vodotoki tega obmocja imajo vecinoma dežno-snežni recni režim z najvišjimi povprecnimi pretoki marca in aprila ter najnižjimi avgusta. Obmocje pripada zmernemu celinskemu podnebju osrednje Slove­nije za katerega je znacilen celinski padavinski režim z povprecno letno kolicino padavin od 1200 do 1300 mm. Povprecna letna temperatura zraka je med 8 °C in 12 °C (ARSO, 2017). Potencialno evapotranspiracijo na Dravskem polju sta oceni-la Kolbezen in Pristov (1998) po Penmanu med 650 in 700 mm/leto. Prestor in Janža (2006) sta po metodi Kennessya ocenila infiltracijo na obrav­navanem obmocju Dravskega polja na od 300 do 400 mm/leto. Na Dravskem polju imamo opraviti s tremi ti- picnimi vodonosniki: prvi (aluvialni) vodonosnik (do 32 m globine), drugi (terciarni) vodonosnik (od 40 – 200 m globine) in tretji (termalni) vodo­nosnik (do 1000 m globine). Najbližje površju in najbolj ranljiv je aluvialni vodonosnik, kateri je bil predmet naših raziskav. Voda v njem se hitro obnavlja, in sicer pretežno iz padavin ter s poni­kanjem površinskih vod. Drugi vodonosnik nima neposrednih povezav s površinskimi vodami in le na dolocenih mestih s prvim vodonosnikom, zato se kolicinsko obnavlja veliko pocasneje (v 1.000 letih). Tretji termalni vodonosnik se nahaja v globljih terciarnih sedimentih in predterciarni podlagi (ARSO, 2009). Prodni (aluvialni) zasip Dravskega polja pred­stavlja dobro prepusten odprt vodonosnik s ko­eficientom hidravlicne prepustnosti od 5·10-4 do 6·10-3 m/s (Urbanc et al., 2014). Povprecna debe­lina vodonosnika je ocenjena na 20 m (Urbanc et al., 2014). Na podlagi suhe prostorninske teže materiala je ocenjena ucinkovita poroznost vo­donosnika približno 0,25, na podlagi prostor­ninske teže naravno vlažnega materiala pa na najmanj 0,15 (Žlebnik, 1982). Povprecna debelina nenasicene cone je ocenjena na podlagi izdelane­ga modela na 8,35 m (Urbanc et al., 2014, Mali & Koroša, 2016), povprecna debelina zasicene cone je 12,05 m (Urbanc et al., 2014), glede na podatke iz leta 1999 pa od 15 do 17 m (Žlebnik & Drobne, 1998). Podzemna voda se v kvartarnem vodonos­niku Dravskega polja pretaka v generalni smeri od zahoda proti vzhodu. Gre za odprti vodono­snik, ki napaja z infiltracijo padavin in s poni­kanjem pohorskih potokov na zahodnem delu Dravskega polja. Smer toka podzemne vode kaže lokalno manjša odstopanja od generalne smeri toka podzemne vode od zahoda proti vzhodu. Vo­donosnik Dravsko polje je eden od glavnih virov pitne vode za obcino Maribor in okoliške obcine. Glede na podatke državnega monitoringa podzemnih vod, je kemijsko stanje vodnega te­lesa Dravska kotlina slabo zaradi vsebnosti ni­tratov in pesticidov (ARSO, 2019). Vzroki so predvsem v intenzivnem kmetijstvu, ki je najbolj prisotno v južnem delu raziskovalnega prostora in manj v severnem delu, kjer leži mesto Maribor. Kmetijstvo je usmerjeno predvsem v živinorejo, med drugim tudi v vzrejo perutnine. Živinoreja je poleg dušika tudi vir za organska onesnaže­vala, na primer farmakološko aktivne snovi, ki se uporabljajo pri vzreji živali. Kmetijstvo je zato osnovni vir slabega stanja podzemne vode zaradi gnojenja poljedelskih površin in obdelave s pesti­cidnimi pripravki. Poleg kmetijske rabe tal na okolje vplivajo ur­bana obmocja z urejeno oz. neurejeno kanaliza­cijsko infrastrukturo. Na obmocjih, kjer ni zgra­jenih kanalizacijskih sistemov, gospodinjstva in stanovanjski objekti uporabljajo greznice. Glede na bazo podatkov Evidence hišnih številk (EHIŠ) lahko ocenimo, da je na celotnem Dravskem polju okoli 130.095 prebivalcev. Kanalizacijsko najbolj urejeno obmocje je severno obmocje, najslabše pa osrednji del Dravskega polja. Na obravnavanem raziskovalnem obmocju je 7 cistilnih naprav. Eden od virov organskih onesnaževal v podze­mni vodi so IED zavezanci (to so zavezanci, ki morajo pridobiti okoljevarstveno dovoljenje v skladu z Direktivo o industrijskih emisijah (In­dustry Emissions Directive), med katere spadajo industrijski obrati, bencinske crpalke, odlaga­lišca, itd. Pri zavezancih IED poznamo razlicne tipe izpustov. To so komunalne odpadne vode, avtopralnice, hladilne vode, odpadne vode iz ke­ micnih cistilnic, tehnološke vode, odpadne vode iz kotlovnic, raznih pralnic, proizvodenj teksti- la, kozmetike, itd. Obmocje Dravskega polja ima dobro razvito prometno infrastrukturo. Od avto­ cest, lokalnih cest, železnic pa tudi letališce. V kategorijo odlagališc na Dravskem polju spadajo komunalna odlagališca ter divja odlagališca, ki so nenadzorovana in še toliko bolj škodljiva za okolje. Na raziskovalnem obmocju Dravskega polja sta dve odlagališci komunalnih odpadkov. Zacasno odlagališce Dogoše in odlagališce na obmocju mesta Maribor - Pobrežje. Obe odlaga­lišci imata status zaprtih odlagališc. Na obmocju Kidricevega sta tudi dve industrijski odlagališci odpadkov, ki sta nastali pri proizvodnji glinice in aluminija. Za podatkovno bazo divjih odlagališc skrbi društvo Ekologi brez meja (2019). V bazi imajo fizicne osebe in organizacije kot registri­rani uporabniki omogocen pregled in vnos loka­cij divjih odlagališc. Po razpoložljivih podatkih registra divjih odlagališc je na Dravskem polju še 416 razlicnih divjih odlagališc. Klasificirana so glede na tip odpadkov (organski, gradbeni, komunalni, kosovni, pnevmatike, motorna vozi- la, salonitne plošce, nevarni odpadki ter sodi z nevarnimi odpadki). Od teh je 268 odlagališc s komunalnimi odpadki, 202 odlagališci z gradbe­nimi odpadki, 160 odlagališc s kosovnimi odpad­ki, 136 odlagališc z biološkimi odpadki, 123 od­lagališc z nevarnimi odpadki, 71 odlagališc, kjer je odložen salonit, 17 odlagališc s pnevmatikami in tri avtomobilska odlagališca. Hidrogeološke razmere na Dravskem polju v casu raziskav Smer toka podzemne vode, na podlagi meritev gladin, kaže lokalno manjša odstopanja od gene-ralne smeri toka podzemne vode od zahoda pro-ti vzhodu (sl. 1). Najmanjša debelina nenasicene cone je v južnem delu vodonosnika na obmocju merilnih mest VP-4, OP-2 in V-25. Najdebelejša nenasicena cona se nahaja na obmocju merilnih mest PAC-5, PAC-2 in PCI-2 v severnem delu vodonosnika. Debelina nasicene plasti je najde­belejša v južnem, spodnjem, delu vodonosnika, medtem ko je nasicena plast najtanjša v severnem delu, ob pobocju Pohorja (Urbanc et al., 2014). Ne glede na vodno stanje smo meritve (vzorcenje) iz­vedli v oktobru (2013, 2014) in aprilu (2014, 2015). V obdobju meritev je bila na Dravskem polju za­beležena najnižja gladina podzemne vode v ok­tobru 2013 (224,13 m n.m.v.), oktobra 2014 pa je bila zabeležena najvišja gladina podzemne vode (256,93 m n.m.v.). V sklopu opravljenih raziskav na Dravskem polju smo ob vsakem vzorcenju podzemne vode izmerili tudi nivo podzemne vode, T, pH, elek­tricno prevodnost (EC) ter oksidacijsko-reduk­cijski potencial (Eh). V casu naših raziskav dolo-canja prisotnosti pesticidov v podzemni vodi so bile dolocene vrednosti pH podzemne vode Dra­vskega polja od 6,64 do 7,82 ter EC med 483 in 1031 µS/cm. Vrednosti EC so v osrednjem in juž­nem delu Dravskega polja višje od 700 µS/cm. Na dolocenih mestih tako na južnem kot severnem delu dosegajo celo vrednosti višje od 900 µS/cm. Vrednosti oksidacijsko-redukcijskega potenciala (Eh) nihajo med 11 in 323 mV. Izmerjene vred­nosti temperature (T) nihajo med 11,1 in 15,8 °C. Izbor pesticidov in njihovo obnašanje Transport pesticidov je odvisen od njihovih fizikalno-kemijskih lastnosti in lastnosti okolja, v katerem potujejo. Zadnja desetletja se je po­ vecalo razumevanje vpliva lastnosti in procesov prisotnosti in razporejanja pesticidov v zemlji­ nah in sedimentih z razlicnimi pedološkimi in geološkimi lastnostmi. Spoznanja temeljijo na podlagi laboratorijskih raziskav (Clausen et al., 2004), terenskih eksperimentov (Boesten and van der Pas, 2000; Funari et al., 1998), regionalnih in nacionalnih programov monitoringov ter študija znacilnosti med stopnjo onesnaženja, razlicnimi hidrogeološkimi znacilnostmi in rabo prostora v zaledju vodnih virov (Gaw et al., 2008; Steele et al., 2008; Worrall and Kolpin, 2004). Razgradnja pesticidov je odvisna od pogojev v okolju, pred­vsem vremenskih razmer (temperature, soncne­ga sevanja, kolicine padavin, drugo), lastnosti tal in sedimentov (aktivnost mikroorganizmov, pedoloških in geoloških znacilnosti). Lastnosti pesticidov, zadrževalni casi podzemne vode, re-doks pogoji in celotna obremenitev so faktorji, ki dolocajo transportne poti in dinamiko pesticidov v vodonosniku. Pesticidi, ki so bili odloženi na površje, migrirajo skozi tla (Oppel et al., 2004; Scheytt et al., 2004) in nenasiceno cono v nasi-ceno cono vodonosnika (Snyder, 2004; Zuehlke et al., 2004). Glavni procesi, ki kontrolirajo organ­ ska onesnaževala med transportom, so sorpcija, ionska izmenjava v vodonosniku in njihova mi-krobiološka razgradnja (Lapworth et al., 2012). Migracija aktivnih snovi in njihovih razgradnih produktov je dolocena s topnostjo v vodi (Water solubility, Sw), hidrofobnostjo oz. hidrofilnostjo (izraženo s porazdelitvenim koeficientom, Kow oz. logKow), koeficientom odvisnim od pH (Dow), koeficientom adsorpcije/desorpcije (izražen kot Koc) ter kislostjo (izraženo s pKa) in hlapnostjo iz vode (izraženo s Henryjevo konstanto). Za boljšo oceno okoljskega tveganja zaradi uporabe pesti­cidov so se razvili razlicni indikatorji ocene tve­ganja (Gutsche & Rossberg, 1997; Padovani et al., 2004; Reus and Leendertse, 2000; Sorensen et al., 2015; van der Werf and Zimmer, 1998) in modeli obnašanja pesticidov v podzemni vodi (Carsel et al., 1985; Jarvis et al., 1991; Tiktak et al., 2004). Za analizo pesticidov v podzemni vodi Dra­vskega polja smo izbrali 15 pesticidov in njiho­vih razgradnih produktov (2,6-diklorobenzamid, alaklor, atrazin, desetilatrazin, desizopropilatra­zin, terbutilazin, desetilterbutilazin, dimetena-mid, klorotoluron, metazaklor, metolaklor, pro-metrin, propazin, simazin in terbutrin) (Tabela 1). V program preiskav je vkljucenih 15 spojin, od tega 11 maticnih spojin in štirje razgradni produkti. Le za šest spojin - terbutilazin, meto­laklor, metazaklor, dimetenamid, klortoluron, je raba pesticidnih pripravkov dovoljena. Ostali so prepovedani oz. so se pa uporabljali v preteklosti. Glede na Seznam registriranih fitofarmacevt­skih sredstev na dan 25.9.2019 (MKGP, 2019) je terbutilazin selektivni herbicid in se skupaj z dimetenamidom uporablja za pridelavo koruze. Po prepovedi uporabe atrazina v EU je terbuti­lazin njegov nadomestek. Desetilterbutilazin je razgradni produkt terbutilazina. Najdemo ga lahko na kmetijskih obdelovalnih obmocjih, v sedimentih ter površinskih in podzemnih vodah. Metolaklor je prav tako herbicid, ki se uporablja za zatiranje nekaterih plevelov v kmetijstvu, ob cestah in pri vzgoji okrasnih rastlin. V zemlji se razgrajuje hitreje, v vodi pocasneje. Klorotoluron se skupaj z ostalimi aktivnimi snovmi uporablja pri zatiranju plevelov ter drugih rastlin, ki mo-tijo rast pšenice, rži ter jecmena (MKGP, 2019). Metazaklor se uporablja pri pridelavi brsticnega ohrovta, gorjušica, oljna ogršcica ter drugih po­dobnih ter okrasnih rastlin (MKGP, 2019). Med Tabela 1. Pesticidi, ki so bili vkljuceni v analizo podzemne vode na Dravskem polju. Table 1. Pesticides included in the analysis of groundwater in the Drava field. 2,6-diklorobenzamid 2008-58-4 razgradni produkt herbicida diklobenila Prepovedan Alaklor 15972-60-8 herbicid Prepovedan Atrazin 1912-24-9 herbicid Prepovedan Desetilatrazin 6190-65-4 razgradni produkt herbicida atrazina Prepovedan Desetilterbutilazin 30125-63-4 razgradni produkt herbicida terbutilazina Dovoljen Desizopropilatrazin 1007-28-9 razgradni produkt herbicida atrazina Prepovedan Dimetenamid 87674-68-8 herbicid Dovoljen Klortoluron 15545-48-9 herbicid Dovoljen Metazaklor 67129-08-2 herbicid Prepovedan Metolaklor 51218-45-2 herbicid Dovoljen Prometrin 7287-19-6 herbicid Prepovedan Propazin 139-40-2 herbicid Prepovedan Simazin 122-34-9 herbicid Prepovedan Terbutilazin 5915-41-3 herbicid Dovoljen Terbutrin 886-50-0 herbicid Prepovedan *CAS št. / CAS no. - registrska številka CAS / CAS ( Chemical Abstracts Service) Registry Number Sl. 1. Karta merilnih mest, hidroizohips in smeri toka podzemne vode na Dravskem polju (april 2014). Fig. 1. Map of the measuring points, hydroisohips and groundwater flow direction in the Drava field (April 2014). najveckrat detektiranimi, tudi v najvišjih kon­centracijah, še vedno najdemo atrazin ter njego­ve razgradne produkte. Atrazin je herbicid, ki se je uporabljal za zatiranje plevela. V Sloveniji je v celoti prepovedan od leta 2003. Razgradna produkta atrazina sta desetilatrazin in desizo­propilatrazin. Zanju veljajo enaki toksikološki zakljucki in enake zahteve, kot za atrazin. Med prepovedanimi sta tudi simazin in propazin. Simazin prištevamo med herbicide iz skupine triazinov. Uporabljal se je za odstranjevanje ple-vela, podobno kot atrazin je sedaj prepovedan v Evropski uniji Direktiva (91/414/EGS). Propazin je herbicid, ki se je uporabljal v obliki škropila, ob ali po sajenju raznih kultur. Stabilen je v nev­tralnih rahlo kislih ali alkalnih medijih. Med prepovedanimi so še diklobenil, alaklor, prome­trin in terbutrin. 2,6-diklorobenzamid je razgra­dni produkt diklobenila, ki se je uporabljal za zatiranje plevelov v sadovnjakih, vinogradih, na­sadih okrasnega grmovja, itd., med drugim tudi ob železniških tirih in postajah. Materiali in metode Dolocitev merilnih mest Ocena reprezentativnosti merilnih mest je na­rejena na osnovi navodil ISO standarda za vzor-cenje podzemne vode (SIST ISO 5667-11:2010). Izbrana merilna mesta so piezometri s podob­nimi lastnostmi, ki lahko vplivajo na ustreznost vzorcenja (globina objekta, vgrajeni materiali, dostopnost, itd.). Merilna mesta so bila dolocena na podlagi razpoložljivih podatkov arhiva Geo-loškega zavoda Slovenije o lokacijah, o litološki zgradbi, tehnicni izvedbi vrtin (globina, premer, lokacija filtrov, itd.), meritvah gladin podzemne vode (GPV), crpalnih poskusih ter o kemijskih analizah vode. V mrežo merilnih mest je bilo vkljucenih 19 merilnih mest, od tega tudi dve mesti, ki sta vkljuceni v državni program monitoringa kemij­skega stanja podzemne vode (LP -1 in P-1). Loka­cije merilnih mest so prikazane na sliki 1. Analiza rabe tal Klasifikacijo rabe prostora smo izvedli z upo­rabo podatkov CORINE 2012 (Corine land cover – CLC) za rabo zemljišc za Evropo (ARSO, 2016) za celotno obmocje Dravskega polja ter za vsako merilno mesto posebej. Na osnovi baze pokrov­nosti tal CLC 2012 in prostorske analize smo do-locili deleže površine posamezne enote pokrov­nosti tal. Razrede pokrovnosti tal smo združili v 4 vecje enote: kmetijske površine (45,65 %), gozd (22,84 %), urbana obmocja (19,65 %) in industrij-ska obmocja (2,26 %), ostalo predstavljajo vod­ne površine (reke, jezera, itd.). Urbana obmocja predstavljajo naselja in zaselki ter vsa infra-struktura, ki služi opravljanju clovekovih dejav­nosti. V kategorijo »industrijskih površin« smo uvrstili industrijske obrate, cestno in železniško omrežje, letališce, kamnolome in odlagališca. V kategorijo kmetijskih zemljišc spadajo njivske površine ter mešane kmetijske površine. Enota gozd združuje vse vrste od listnatega, mešanega in iglastega gozda ter grmicasti gozd. Obdelavo podatkov in izracune smo izvedli z uporabo pro-gramske opreme Statistica (Stat Soft Inc., 2012), prostorsko analizo pa z uporabo ArcMap (ESRI Inc., 2004). Napajalna zaledja merilnih mest Karakteristike napajalnega zaledja vrtin smo dolocili za vsako vrtino glede na hidrogeološke znacilnosti vodonosnika, izražene s hitrostjo in smerjo toka podzemne vode (Koroša, 2019). Pre­tok podzemne vode smo izracunali po Darcyjevi enacbi. Koeficient prepustnosti (K) smo za vsa­ko vzorcno mesto ocenili na podlagi predhodnih raziskav crpalnih poskusov in drugih raziskav (Krivic et al., 2012; Brencic & Ratej 2006; Urbanc et al., 2014; Brencic, 1998; Brencic, 2004). Gradi­ent je bil dolocen na podlagi izrisanih hidroizo-hips. Razdaljo obmocja napajanja smo dolocili na podlagi izracuna hitrosti toka podzemne vode v smeri gorvodno v obdobju enega leta v pravoko­tni smeri na hidroizohipse. Ker ne gre za stalno crpanje vode iz vzorcevanih objektov, smo napa­jalno obmocje omejili na kot 30°, kot doloca meto­dologija v Pravilniku o kriterijih za dolocitev vo­dovarstvenega obmocja (Uradni list RS, 2004b). Za vsako merilno mesto so bili doloceni podatki o rabi tal ter potencialnih onesnaževalcih. Vzorcenje Za dolocitev pesticidov v podzemni vodi Dra­vskega polja smo izpeljali štiri vzorcenja v letih 2013-2015, in sicer v jesenskem (oktober 2013, 2014) in pomladnem (april 2014, 2015) obdobju. Na obravnavanem obmocju smo odvzeli vzorce pod-zemne vode za kvantitativno kemijsko analizo podzemne vode za pesticide in njihove razgradne produkte na devetnajstih merilnih mestih. Vzor-cenje podzemne vode smo izvedli skladno z do-locili standarda SIST ISO 5667-11:2010. Z vzorci podzemne vode smo ravnali skladno z dolocili standarda SIST ISO 5667-3. Vzorcenje podzemne vode je potekalo s crpalko Grundfos MP-1TM, katere pretok je bil 0,2 l/s, na globini od 3 m do 16 m, glede na gladino podzemne vode v meril­nem mestu. Za kvantitativno kemijsko analizo pesticidov smo odvzeli 1 l vode v rjavo stekleni- co z zamaški s PTFE linerjem. Pri vzorcenju smo uporabili zašcitne rokavice za enkratno uporabo, ki se po vsakem vzorcenju zavržejo. Vsi vzorci so bili dostavljeni v laboratorij v najvec 6 urah, ter nadalje obdelani po postopkih dolocenih z meril-no metodo. Skupno smo odvzeli 76 vzorcev vode. Analizne metode Kvantitativne kemijske analize pesticidov v podzemni vodi so bile izvedene v laboratoriju JP VO-KA d.o.o. Uporabljena je bila modificira­na metoda EPA 525.2, ki temelji na ekstrakciji na trdno fazo (SPE) in uporabi metode sklopitve plinske kromatografije in masne spektrometrije (GC-MS). Podrobneje so metodo opisali Auer­sperger et al. (2005). Uporabljena merilna metoda je validirana. Vrednotenje razmerij pesticidov in njihovih razgradnih produktov Razmerje DAR, ki sta ga prvic predstavi-la Adams & Thurman (1991), pojasnjuje vseb­nosti razgradnega produkta (desetilatrazin) in primarne spojine (atrazin). DAR je uporaben za namen dolocitve »starosti« onesnaženja. Z DAR smo izracunali razmerje med desetilatrazinom in atrazinom, za razdelitev tockovnih in razpršenih virov onesnaženja v podzemni vodi. Majhno raz­merje DAR pomeni, da je prisotnega vec atrazi­na v primerjavi z desetilatrazinom, kar nakazuje na »sveže« onesnaženje in je lahko tudi kazalnik tockovnega vira onesnaženja. Na osnovi rezulta­tov vsebnosti terbutilazina in desetilterbutilazi­na, lahko tako kot razmerje DAR, izracunamo tudi razmerje med desetilterbutilazinom in ter­butilazinom (DTA/TBA). Milan et al. (2015) so razmerje DTA/TBA uporabili v podzemni vodi za analizo interakcije med herbicidom in tlemi. Razmerje, manjše od 1, kaže na tockovni vir one-snaženja, saj desetilterbutilazin pocasneje izgi­nja v nenasiceni coni kot terbutilazin. Tabela 2. Statisticna analiza meritev pesticidov v podzemni vodi Dravskega polja. Table 2. Statistical analysis of pesticide measurements in the Drava field groundwater. 2,6-diklorobenzamid 0,002 0,0067 3 0,01 0,01 0,01 0,01 0 Alaklor 0,002 0,0067 - Atrazin 0,002 0,0067 76 0,07 0,05 0,01 0,23 0,06 Desetilatrazin 0,002 0,0067 76 0,08 0,06 0,01 0,21 0,06 Desetilterbutilazin 0,002 0,0067 34 0,01 0,01 0,01 0,03 0,01 Desizopropilatrazin 0,01 0,0033 1 0,04 0,04 0,04 0,04 - Dimetenamid 0,002 0,0067 - Klortoluron 0,002 0,0067 3 0,01 0,01 0,01 0,01 0 Metazaklor 0,005 0,017 - Metolaklor 0,002 0,0067 40 0,02 0,01 0,01 0,07 0,02 Prometrin 0,002 0,0067 8 0,03 0,02 0,01 0,05 0,02 Propazin 0,002 0,0067 4 0,01 0,01 0,01 0,01 0 Simazin 0,002 0,0067 21 0,01 0,01 0,01 0,03 0,01 Terbutilazin 0,001 0,0033 24 0,01 0,01 0,01 0,05 0,01 Terbutrin 0,005 0,017 - *LOD - meja detekcije/Limit of detection; LOQ - meja dolocljivosti/Limit of quantification; N – št. dolocenih vzorcev nad LOQ/No. of samples above the LOQ; Povp. - povprecna vrednost/Average value; Md – mediana/Median; Min. – najmanjša vrednost/Minimum value; Max. – najvecja vrednost/Maximum value; Std.Dev. – standardna deviacija/Standard deviation Rezultati in diskusija Atrazin in njegov razgradni produkt desetila- Prisotnost pesticidov v podzemni vodi trazin sta bila dolocena v vseh vzorcih (76) pod- zemne vode (sl. 2). Sledijo jima metolaklor (40), Rezultati prisotnosti in statistika meritev razgradni produkt desetilterbutilazin (34), ter­pesticidov v podzemni vodi Dravskega polja je butilazin (24), simazin (21), prometrin (8), propa­prikazana v tabeli 2. Nekateri od preiskovanih zin (4), razgradni produkt 2,6-diklorobenzamid pesticidov niso bili zaznani niti enkrat. Takšni in klorotoluron (3) ter razgradni produkt desizo­pesticidi, ki niso bili doloceni nad spodnjo mejo propilatrazin (1). Izmerjena vsebnost navedenih dolocljivosti (LOQ) ali mejo zaznavanja upo-spojin je bila nad LOQ. Izmerjena vsebnost osta­rabljene merilne metode za posamezno spojino lih spojin ne presega vrednosti LOQ za posame-(LOD) so: alaklor, dimetenamid, metazaklor, ter-zno spojino (sl. 2). butrin (Tabela 2). Sl. 2. Pogostost pojavljanja pesticidov v podzemni vodi Dravskega polja. Fig. 2. Frequency of pesti­cide occurrence in Dravsko polje groundwater. Sl. 3. Koncentracije izmerje­nih pesticidov v podzemni vodi Dravskega polja. Fig. 3. Concentrations of mea­sured pesticides in Dravsko polje groundwater. 2,6-diklorobenzamidAtrazinDesetilatrazinDesetilterbutilazinDesizopropilatrazinKlortoluronMetolaklor PrometrinPropazinSimazinTerbutilazin Mediana / Median 25%-75% n = Št. detekcij / No. of detections Na sliki 3 so predstavljene minimalne, pov­precne in maksimalne vrednosti izbranih pesti­cidov v podzemni vodi Dravskega polja. Tisti, ki niso bili niti enkrat doloceni nad mejo LOQ, niso prikazani. Visoke koncentracije dosegata pesticid atrazin (maks. 0,23 µg/l; min. 0,01 µg/l; povpr. 0,07 µg/l) in njegov razgradni produkt de­setilatrazin (max. 0,21 µg/l; min. 0,01 µg/l; povpr. 0,08 µg/l), ki mestoma presegata mejno vrednost doloceno s Uredbo o stanju podzemnih voda (Uradni list RS, 2009), 0,1 µg/l. Ostale preiskova­ne spojine niso bile zaznane v povišanih koncen­tracijah, nad mejno vrednostjo 0,1 µg/l (Tabela 2). Nekateri pesticidi so se pojavili samo na enem merilnem mestu. Razgradni produkt 2,6-dikloro­benzamid se je trikrat pojavil na merilnem mes-tu V-25. Pojav 2,6-diklorobenzamida na meril­nem mestu V-25 je glede na zaledje najverjetneje kmetijskega izvora. Klorotoluron je bil zaznan trikrat samo na merilnem mestu GPP-3, ki ima v svojem širokem zaledju veliko kmetijskih po­vršin, kljub temu, da je njegova lokacija v gozdu. Glede na to, da je zaznan samo na tem merilnem mestu, je možen izvor tudi v nelegalnih zasutih jamah in odloženih materialih v gozdu. Prepove­dan pesticid propazin je bil zaznan v vseh štirih vzorcenjih samo na merilnem mestu HP-3. Tudi to merilno mesto, ni tipicno kmetijsko, leži ob prometnici. V njegovem širšem zaledju pa najde-mo tudi kmetijske površine (Tabela 3). Glede na to, da so bili ti trije pesticidi zaznani samo na teh merilnih mestih, lahko recemo, da gre v teh pri­merih verjetno za tockovna onesnaženja. Prostorska in casovna porazdelitev pesticidov v podzemni vodi glede na rabo prostora Za namen prostorskega prikaza prisotnosti pesticidov v obdobju naših raziskav so na sliki 4 prikazane komulativne vrednosti (vsota) štirih vzorcenj izmerjenih vsebnostih šestih spojin, atrazina, desetilatrazina in simazina, (sl. 4a) ter terbutilazina, desetilterbutilazina, metolaklora, (sl. 4b), ki so bili najveckrat zaznani v podzemni vodi Dravskega polja. Izmerjene vsebnosti pesti­cidov, ki so prepovedani za uporabo so prikazane na sliki 4a. Najvecje vrednosti atrazina in dese­tilatrazina so prisotne na obmocju južnega dela Dravskega polja, kjer je kmetijstvo sedaj in je bilo tudi v preteklosti najbolj intenzivno. Sima­zin se pojavlja le tockovno (sl. 4a). Vsote izmer­jenih vsebnosti pesticidov, katerih raba je dovo­ljena, so prikazane na sliki 4b. Vsote izmerjenih vsebnosti terbutilazina, desetilterbutilazina in metolaklora kažejo drugacno razporeditev po vodonosniku. Terbutilazin in desetilterbutilazin se pojavljata po celem vodonosniku, izmerjene vsebnosti metolaklora so vecje v zahodnem delu vodonosnika. Najvišje vrednosti metolaklora so se pojavile na merilnem mestu P-1 (0,072 µg/l). Sl. 4. Prostorski prikaz komulativnih vrednosti (vsota): a) atrazina, desetilatrazina in simazina; b) terbutilazina, desetilter­ butilazina in metolaklora. Fig. 4. Spatial representation of the cumulative values (sum) of: a) atrazine, desethylatrazine and simazine b) terbuthylazine, desethylterbuthylazine and metolachlor. Tabela 3. Podatki o zaledju posamenega merilnega mesta na Dravskem polju. Table 3. Background data of each measuring point in the Dravsko polje. DP-3 6656 5944 GPP-1 963 0 GPP-2 3144 0 GPP-3 1860 0 HP-3 8609 5791 PAC-2 8375 9218 PAC-5 6011 12222 PBA-3 8022 6839 PCI-2 7456 8307 LP-1 1387 0 OP-10 3996 486 OP-2 1297 510 OP-5 6382 3399 OP-6 7597 3908 P-0 2363 686 P-1 4537 3821 P-3 3934 1891 V-25 2141 0 VP-4 10455 5520 0 0 0 0 8 557 3821 0 2839 0 0 0 0 858 0 0 467 0 0 848 0 0 0 1094 779 28 100 25 0 115 74 159 813 131 466 74 0 858 63,54 96,46 99,25 0 10,43 39,61 77,2 14,07 86,46 89,68 92,01 94,71 58,59 37,21 96,6 89,2 29,92 93,13 54,67 31,72 0 0 0 31,59 38,94 0 11,87 2,49 0 7,99 5,29 12,75 43,24 3,4 3,74 0 0,18 40,07 4,61 0 0 0 1,76 12,95 22,79 6,02 8,77 7,29 0 0 0 0 0 0 22,28 6,69 0 0,130 0 3,540 0 0,750 0 100 0 3 56,22 0 1 8,5 2 0 0,01 2 0 68,04 4 9 2,28 1 0 3,03 0 1 00 0 00 3 28,66 0 0 19,55 0 2 00 1 7,060 0 47,80 4 00 5 5,26 0 1 63,7 100,0 100,0 100,0 66,7 48,1 77,2 82,1 88,8 92,7 92,0 94,7 87,3 56,8 96,6 96,3 77,7 93,1 59,9 36,3 0,0 0,0 0,0 33,4 51,9 22,8 17,9 11,3 7,3 8,0 5,3 12,8 43,2 3,4 3,7 22,3 6,9 40,1 Podatki za dolocitev prispevnega oz. napa­jalnega obmocja za posamezno merilno mesto so zbrani v tabeli 3. Na podlagi povprecnega koefi­cienta prepustnosti (3,5·10-3 m/s) in povprecnega gradienta (0,004), smo izracunali povprecno po­vršino zaledja za posamezno merilno mesto za obdobje enega leta. Povprecna površina zaledja meri 1,14 km2. Na osnovi baze pokrovnosti tal CLC 2012 in prostorske analize smo dolocili de­leže posamezne enote pokrovnosti tal za zaledje vsakega merilnega mesta. Merilna mesta z izra­zito kmetijskim zaledjem (nad 80 %) so GPP-1, GPP-2, PCI-2, LP-1, OP-10, OP-2, P-0, P-1 in V-25. Vrtina, pri kateri v zaledju prevladuje gozd (nad 80 %), je GPP-3. 52 % urbanega in industrij­skega zaledja skupaj predstavlja zaledje pri vrti­ni PAC-2. Pri ostalih vrtinah je zaledje mešano (Tabela 3). Za prikaz prisotnosti pesticidov v podzem­ni vodi na Dravskem polju smo uporabili vsote povprecnih vrednosti vseh pesticidov za merilno mesto. Prostorski prikaz vsote pesticidov s po­datki o rabi tal v zaledju merilnih mest je pri­kazan na sliki 5. Podzemna voda Dravskega po­lja v delu južneje od merilnega mesta OP-5 kaže vecjo obremenjenost s pesticidi, kot v severnem delu, kjer se nahajajo urbana obmocja in mesto Maribor. Vsota pesticidov na dolocenih mestih v južnem delu presega mejo dovoljenega glede na Pravilnik o pitni vodi (Uradni list RS, 2004a) Pro-storska porazdeljenost vsote pesticidov sovpada z zaledjem vrtin. V južnem delu vodonosnika je intenzivnejša kmetijska raba prostora. To se od­ raža tudi v koncentracijah pesticidov v podzemni vodi (sl. 5). Iz analize prostora zaledja merilnih mest je razvidno, da gre v veliki meri za mešano rabo prostora. Zaradi tega smo združili rabo prosto­ra samo v dve kategoriji: v skupino I kmetijska obmocja in gozd ter v skupino II urbana in in-dustrijska obmocja (Tabela 3). Iz diagrama rabe prostora in skupne vsote pesticidov (sl. 6) je razvi­dno, da v severnem delu Dravskega polja, kjer je v zaledju merilnih mest vec ko 10 % urbanih po­vršin, povprecne vrednosti skupnih pesticidov ne presegajo 0,15 µg/l. V osrednjem in južnem delu, kjer je zaledje merilnih mest 90 % kmetijskih po­vršin, so povprecne vrednosti skupnih pesticidov do 0,45 ug/l. Na južnem delu Dravskega polja iz­stopajo merilna mesta VP-4, HP-3 in P-3, gre za Sl. 5. Prostorska porazdelitev povprecne vsote pesticidov v podzemni vodi Dravskega polja. Fig. 5. Spatial distribution of the sum of pesticides in Dravsko polje aquifer. merilna mesta, ki imajo v svojem ožjem zaledju vecji delež urbane in industrijske rabe tal, širše gledano pa so na obmocju kmetijskih površin in gozda, ki jim pripisujemo vpliv na prisotnost pe­ sticidov v vodi. Za vsa merilna mesta je znacilna tudi neposredna bližina ceste, bodisi lokalne ces­te ali avtoceste ter prisotnost divjih odlagališc v zaledju (Tabela 3). Razmerje pesticidov in njihovih razgradnih produktov V podzemni vodi Dravskega polja se pojav­ljata pesticida atrazin in terbutilazin in njuni razgradni produkti desetilatrazin, deizopropila­trazin in desetilterbutilazin. Prisotnost atrazina v povecanih koncentracijah v podzemni vodi na nekaterih mestih lahko razložimo kot rezultat njegove uporabe v preteklosti in njegove obstoj­nosti v okolju. Razmerje DAR smo uporabili pri dolocitvi »starosti« onesnaženja z atrazinom in njegovim razgradnim produktom desetilatrazi­nom. Majhno razmerje DAR kaže na »sveže« one-snaženje in je lahko kazalnik tockovnega vira onesnaženja. Pri vseh 76 vzorcih podzemne vode Dravskega polja smo izracunali koeficient DAR od 0,54 (P-0) do 3,18 (VP-4). Najmanjše vrednosti so bile dolocene v tocki P-0 (0,54 – okt. 2013, 0,55 –apr. 2014). Povprecne vrednosti koeficient DAR so nizke v tockah PBA-3 (0,62), GPP-3 (0,75), HP-3 (0,76), OP-10 (0,81), PAC-5 (0,93), in GPP-2 (0,96). Na skoraj polovico merilnih mest so vred­ nosti DAR nižje od 1, kar je presenetljivo glede na to, da je prepoved uporabe atrazina v veljavi že dalj casa. Visoka pojavnost atrazina je lahko posledica starih bremen in zasutih gramoznic, zaradi pocasne razgradnje in hidrogeoloških po­gojev ali pa uporabe v kmetijstvu po uveljavitvi prepovedi. Na osnovi rezultatov vsebnosti terbutilazina in desetilterbutilazina smo izracunali tudi raz­merje med desetilterbutilazinom in terbutilazi­nom (DTA/TBA) (sl. 8). Razmerje, manjše od 1, kaže na tockovni vir onesnaženja, saj desetilter­butilazin pocasneje izginja v nenasiceni coni kot terbutilazin. Razmerja DTA/TBA ni bilo mož-no izracunati za vsa merjenja na vseh merilnih mestih, saj so bile koncentracije terbutilazina in/ ali desetilterbutilazina na nekaterih mestih pod LOD. V našem primeru smo lahko DTA/TBA iz­racunali na štirih razlicnih tockah (sl. 9). Najniže je bil izracunan na tocki VP-4 (0,24 – apr. 2015), najviše pa v tocki P-0 (2,97 – okt. 2014). Na meril­nih mestih OP-2 in P-0 se terbutilazin in desetil­terbutilazin skupaj pojavita v vseh štirih vzorce­njih. Na ostalih mestih se pojavita le v dolocenih serijah. Glede na dejstvo, da je atrazin po prepove­di uporabe zamenjal terbutilazin, je na sliki 9 prikazano razmerje med vrednostmi DAR in vrednostmi DTA/TBA za merilna mesta P-0, V-25, OP-2 in VP-4. Iz grafa (sl. 9) vidimo, da je na merilnem mestu VP-4 DAR najvišji, medtem, ko je DTB/TBA najnižji. Obratno je na merilnem mestu P-0. Merilno mesto VP-4 spada med me-rilna mesta, ki imajo v svojem ožjem zaledju zna-cilen delež urbane in industrijske rabe tal, kar 3,50 3,00 2,50 2,00 1,50 1,00 0,50 0,00 VP-4 PAC-2 PCI-2 P-3 LP-1 OP-5 V-25 OP-2 DP-3 P-1 OP-6 GPP-1 P-0 GPP-2 PAC-5 OP-10 HP-3 GPP-3 PBA-3 DAR DTA/TBA DAR 2,50 2,00 1,50 1,00 0,50 0,00 3,50 3,00 VP-4 2,50 2,00 1,50 1,00 P-0 y = -0,9742x + 2,9439 R˛ = 0,8004 0,50 0,00 0,00 0,50 1,00 1,50 2,00 2,50 DTB/TBA Sl. 7. Povprecno razmerje DAR. Fig. 7. Average ratio DAR. Sl. 8. Razmerje DTA/TBA po posameznih merilnih mestih. Fig. 8. DTA/TBA ratio. Sl. 9. Razmerje med vrednostmi DAR in vrednostmi DTA/TBA. Fig. 9. Relationship between DAR values and DTA / TBA values. lahko pojasni nizko razmerje med vrednostmi DAR in DTA/TBA in kaže na sveže onesnaženje z terbutilazinom. Vrednosti nakazujejo, da je na merilnem mestu, kjer je DAR visok, vec razgra­dnega produkta desetilatrazina, kar pomeni, da atrazin ni bil v uporabi že nekaj casa, hkrati pa je na istem merilnem mestu, vecja koncentraci­ja terbutilazina v primerjavi z desetilterbutila­zinom, kar nakazuje na uporabo le tega. Iz tega lahko sklepamo, da je bila uporaba atrazina že pred nekaj casa opušcena, ter nadomešcena z uporabo terbutilazina. Medtem, ko bi lahko na merilnih mestih z obratnimi vrednostmi sklepali nasprotno. Kljub temu, pa je pri takšni interpre­taciji potrebno pogledati široko, ter upoštevati tudi razlicne hidrogeološke parametre, ki lahko vplivajo na koncentracijo pesticidov v podzemni vodi. Ena od teh je debelina nenasicene cone, ki je na merilnem mestu VP-4 manjša v primerjavi z drugimi. Glede na to, da so pa vrednosti DTB/ TBA nižje od 1, lahko sklepamo tudi na tockovno onesnaženje. Zakljucki Vodonosnik Dravskega polja je zaradi rabe prostora in dejavnosti podvržen razlicnim vpli­vom iz kmetijstva, urbanega okolja, industrije, itd. Najvecji delež rabe prostora predstavljajo kmetijske površine, ki so tudi glavni vir pestici­dov v okolju in podzemni vodi. V naši raziskavi smo prišli do naslednjih zakljuckov: Po celotnem Dravskem polju smo potrdili po­gosto pojavljanje pesticidov, kateri lahko doseže­jo tudi koncentracije, ki lahko predstavljajo tudi tveganja za zdravje ljudi (WHO, 2017). Atrazin in njegov metabolit desetilatrazin sta še vedno, kljub vec desetletni prepovedi uporabe fitofarmacevtskih sredstev na osnovi atrazina, najpogosteje in v najvišjih koncentracijah zazna­ni spojini v podzemni vodi Dravskega polja. 2,6-diklorobenzamid (razgradni produkt diklobenila), klorotoluron, metolaklor, propazin, prometrin, simazin, terbutilazin in desetilterbu­tilazin (razgradni produkt terbutilazina), so bili doloceni v vsebnostih, katere so pod mejo dovo­ljenega, glede na pravilnik o pitni vodi (Uradni list RS, 2004a). Alaklor, dimetenamid, metazaklor in ter­butrin niso bili zaznani v podzemni vodi Dra­vskega polja. Pojav pesticidov klorotolurona, propazina in razgradnega produkta diklobenila 2,6- dikloro­benzamida na posameznih merilnih mestih na­kazuje na lokalno onesnaženje omejenega obmo-cja. Rezultati potrjujejo, da je pojavnost pesticidov v podzemni vodi povezana z rabo prostora v za­ledju. Povišane vrednosti pesticidov se pojavljajo v južnem delu Dravskega polja, kar sovpada z in-tenzivnejšo kmetijsko rabo tal na tem obmocju. V severnem delu, z vecjim deležem urbanih in in-dustrijskih površin (skupina II) so koncentracije pesticidov manjše. Izmed vseh merilnih mest izstopajo tri (VP­ 4, HP-3 in P-3), ki imajo v svojem ožjem zaledju urbano in industrijsko rabo tal, širše gledano pa so na obmocju kmetijskih površin in gozda, kar verjetno vpliva na višje zaznane koncentracije pesticidov v podzemni vodi. Metodologijo vrednotenja razmerij med raz­gradnim produktom in primarnim pesticidom (DAR in DTA/TBA) se je izkazala za uporabno pri dolocitvi »starosti« onesnaženja iz naslova atrazin in terbutilazina. Na skoraj polovici merilnih mest so vrednosti DAR nižje od 1, kar je presenetljivo glede na to, da je prepoved uporabe atrazina v veljavi že dalj casa. Visoka pojavnost atrazina je lahko posle­dica starih bremen zaradi pocasne razgradnje in hidrogeoloških pogojev ali pa uporabe po uvelja­vitvi prepovedi. Pojav pesticidov z naslova prepovedanih fito­farmacevtskih pripravkov kaže na možnost pre­povedane uporabe na kmetijskih površinah ali na vir »na crno« odloženih v zasutih gramozni­cah. Te snovi se lahko tudi dalj casa akumulirajo (zadržujejo) v nenasiceni coni. Zahvala Raziskava je bila narejena v okviru Programa usposabljanja mladih raziskovalcev ter v okviru Raziskovalnega programa P1-0020, ki se izvajata na Geološkem zavodu Slovenije in ju financira Javna agencija za raziskovalno dejavnost. Raziskave so bile narejene tudi v okvirih projekta GeoERA (Hover), ki prejel sredstva raziskovalnega in inovacijskega pro-grama Evropske unije Obzorje 2020 (v skladu s spora­zumom št. 731166). Literatura Adams, C.D. & Thurman, E.M. 1991: Formation and transport of desethylatrazine in the soil and vadose zone. 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Pest management science, 70: 1840-1849. https:// doi.org/10.1002/ps.3729 WHO, World Health Organization 2017: SZO ­Guidelines for Drinking – water Quality. https://apps.who.int/iris/bitstream/han­ d le/10665/254637/9789241549950 -eng. pdf;jsessionid=3D049E809F7CD80889A­ 604FA649BE1CD?sequence=1 (17.12.2019) Worrall, F., Kolpin, D.W. 2004: Aquifer vulnera­bility to pesticide pollution–combining soil, land-use and aquifer properties with mo­lecular descriptors. Journal of Hydrology, 293: 191-204. https://doi.org/10.1016/j. jhydrol.2004.01.013 Zuehlke, S., Duennbier, U., Heberer, T. & Fritz, B. 2004: Analysis of Endocrine Disrupting Steroids: Investigation of Their Release into the Environment and Their Behavior During Bank Filtration. Ground Water Monitoring & Remediation; 24: 78-85. https://doi. org/10.1111/j.1745-6592.2004.tb00715.x Žlebnik, L. 1982. Hidrogeološke razmere na Dravskem polju. Geologija, 25/1: 151–164. https://doi.org/10.5474/geologija.1991.008 Žlebnik, L. & Drobne, F. 1998. Pliocenski vodo­nosniki – pomemben vir neoporecne pitne vode za ptujsko – ormoško regijo. Geologija, 41: 339–354. https://doi.org/10.5474/ geologija.1998.017 Yadav, I.C. & Devi NL 2017: Pesticides classificati­on and its impact on human and environment. Environmental Science and Engineering, 140 –158. Navodila avtorjem GEOLOGIJA objavlja znanstvene in strokovne clanke s podrocja geologije in sorodnih ved. Revija izhaja dvakrat letno. Clanke recenzirajo domaci in tuji strokovnjaki z obravnavanega podrocja. Ob oddaji clankov avtorji predlagajo tri recenzente, uredništvo si pridržuje pravico do izbire recenzentov po lastni presoji. Avtorji morajo clanek popraviti v skladu z recenzentskimi pripombami ali utemeljiti zakaj se z njimi ne strinjajo. Avtorstvo: Za izvirnost podatkov, predvsem pa mnenj, idej, sklepov in citirano literaturo so odgovorni avtorji. Z objavo v GEOLOGIJI se tudi obvežejo, da ne bodo drugje objavili prispevka z isto vsebino. Avtorji z objavo prispevka v GEOLOGIJI potrjujejo, da se strinjajo, da je njihov prispevek odprto dostopen z izbrano licenco CC-BY. Jezik: Clanki naj bodo napisani v angleškem, izjemoma v slovenskem jeziku, vsi pa morajo imeti slovenski in angleški izvlecek. Za prevod poskrbijo avtorji prispevkov sami. Vrste prispevkov: Izvirni znanstveni clanek Izvirni znanstveni clanek je prva objava originalnih razisko­ valnih rezultatov v takšni obliki, da se raziskava lahko ponovi, ugotovitve pa preverijo. Praviloma je organiziran po shemi IMRAD (Introduction, Methods, Results, And Discussion). Pregledni znanstveni clanek Pregledni znanstveni clanek je pregled najnovejših del o dolocenem predmetnem podrocju, del posameznega razisko­ valca ali skupine raziskovalcev z namenom povzemati, analizirati, evalvirati ali sintetizirati informacije, ki so že bile publicirane. Prinaša nove sinteze, ki vkljucujejo tudi rezultate lastnega raziskovanja avtorja. Strokovni clanek Strokovni clanek je predstavitev že znanega, s poudarkom na uporabnosti rezultatov izvirnih raziskav in širjenju znanja. Diskusija in polemika Prispevek, v katerem avtor ocenjuje ali komentira neko delo, objavljeno v GEOLOGIJI, ali z avtorjem strokovno polemizira. Recenzija, prikaz knjige Prispevek, v katerem avtor predstavlja vsebino nove knjige. Oblika prispevka: Besedilo pripravite v urejevalniku Micro­soft Word. Prispevki naj praviloma ne bodo daljši od 20 strani formata A4, v kar so vštete tudi slike, tabele in table. Le v izjemnih primerih je možno, ob predhodnem dogovoru z uredništvom, tiskati tudi daljše prispevke. Clanek oddajte uredništvu vkljucno z vsemi slikami, tabelami in tablami v elektronski obliki po naslednjem sistemu: - Naslov clanka (do 12 besed) - Avtorji (ime in priimek, poštni in elektronski naslov) - Kljucne besede (do 7 besed) - Izvlecek (do 300 besed) - Besedilo - Literatura - Podnaslovi slik in tabel - Tabele, Slike, Table Citiranje: V literaturi naj avtorji prispevkov praviloma upoštevajo le objavljene vire. Porocila in rokopise naj navajajo le v izjemnih primerih, z navedbo kje so shranjeni. V seznamu literature naj bodo navedena samo v clanku omenjena dela. Citirana dela, ki imajo DOI identifikator (angl. Digital Object Identifier), morajo imeti ta identifikator izpisan na koncu citata. Za citiranje revije uporabljamo standardno okrajšavo naslova revije. Med besedilom prispevka citirajte samo avtorjev priimek, v oklepaju pa navajajte letnico izida navedenega dela in po potrebi tudi stran. Ce navajate delo dveh avtorjev, izpišite med tekstom prispevka oba priimka (npr. Plenicar & Buser, 1967), pri treh ali vec avtorjih pa napišite samo prvo ime in dodajte et al. z letnico (npr. Mlakar et al., 1992). Citiranje virov z medmrežja v primeru, kjer avtor ni poznan, zapišemo (Internet 1). V seznamu literaturo navajajte po abecednem redu avtorjev. Imena fosilov (rod in vrsta) naj bodo napisana poševno, imena višjih taksonomskih enot (družina, razred, itn.) pa normalno. Imena avtorjev taksonov naj bodo prav tako napisana normalno, npr. Clypeaster pyramidalis Michelin, Galeanella tollmanni (Kristan), Echinoidea. Primeri citiranja clanka: Mali, N., Urbanc, J. & Leis, A. 2007: Tracing of water movement through the unsaturated zone of a coarse gravel aquifer by means of dye and deuterated water. Environ. geol., 51/8: 1401–1412. https://doi.org/10.1007/s00254-006-0437-4 Plenicar, M. 1993: Apricardia pachiniana Sirna from lower part of Liburnian beds at Divaca (Triest-Komen Plateau). Geologija, 35: 65–68 Primer citirane knjige: Flel, E. 2004: Mikrofacies of Carbonate Rocks. Springer Verlag, Berlin: 976 p. Jurkovšek, B., Toman, M., Ogorelec, B., Šribar, L., Drobne, K., Poljak, M. & Šribar, Lj. 1996: Formacijska geološka karta južnega dela Tržaško-komenske planote – Kredne in paleogenske kamnine 1: 50.000 = Geological map of the southern part of the Trieste-Komen plateau – Cretaceous and Paleogene carbonate rocks. Geološki zavod Slovenije, Ljubljana: 143 p., incl. Pls. 23, 1 geol. map. Primer citiranja poglavja iz knjige: Turnšek, D. & Drobne, K. 1998: Paleocene corals from the northern Adriatic platform. In: Hottinger, L. & Drobne, K. (eds.): Paleogene Shallow Benthos of the Tethys. Dela SAZU, IV. Razreda, 34/2: 129–154, incl. 10 Pls. Primer citiranja virov z medmrežja: Ce sta znana avtor in naslov citirane enote zapišemo: Carman, M. 2009: Priporocila lastnikom objektov, zgrajenih na nestabilnih obmocjih. Internet: http://www.geo-zs. si/UserFiles/1/File/Nasveti_lastnikom_objektov_na_ nestabilnih_tleh.pdf (17. 1. 2010) Ce avtor ni poznan zapišemo tako: Internet: http://www.geo-zs.si/ (22. 10. 2009) Ce se navaja vec enot z medmrežja, jim dodamo še številko: Internet 1: http://www.geo-zs.si/ (15. 11. 2000) Internet 2: http://www.geo-zs.si/ (10. 12. 2009) Slike, tabele in table: Slike (ilustracije in fotografije), tabele in table morajo biti zaporedno oštevilcene in oznacene kot sl. 1, sl. 2 itn., oddane v formatu TIFF, JPG, EPS ali PDF z locljivostjo 300 dpi. Le izjemoma je možno objaviti tudi barvne slike, vendar samo po predhodnem dogovoru z uredništvom. Ce avtorji oddajo barvne slike bodo te v barvah objavljene samo v spletni razlicici clanka. Pazite, da bo tudi slika tiskana v sivi tehniki berljiva. Graficni materiali naj bodo usklajeni z zrcalom revije, kar pomeni, da so široki najvec 172 mm (ena stran) ali 83 mm (pol strani, en stolpec) in visoki najvec 235 mm. Vecjih formatov od omenjenega zrcala GEOLOGIJE ne tiskamo na zgib, je pa možno, da vecje oziroma daljše slike natisnemo na dveh straneh (skupaj na levi in desni strani) z vmesnim "rezom". V besedilu prispevka morate omeniti vsako sliko po številcnem vrstnem redu. Dovoljenja za objavo slikovnega gradiva iz drugih revij, publikacij in knjig, si pridobijo avtorji sami. Ce je clanek napisan v slovenskem jeziku, mora imeti celotno besedilo, ki je na slikah in tabelah tudi v angleškem jeziku. Podnaslovi naj bodo cim krajši. Korekture: Avtorji prejmejo po elektronski pošti clanek v avtorski pregled. Popravijo lahko samo tiskarske napake. Krajši dodatki ali spremembe pri korekturah so možne samo na avtorjeve stroške. Prispevki so prosto dostopni na spletnem mestu: http://www. geologija-revija.si/ Oddaja prispevkov: Avtorje prosimo, da prispevke oddajo v elektronski obliki na naslov uredni{tva: GEOLOGIJA Geolo{ki zavod Slovenije Dimi~eva ulica 14, SI-1000 Ljubljana bernarda.bole.geo-zs.si ali urednik.geologija-revija.si Uredni{tvo Geologije Instructions for authors Scope of the journal: GEOLOGIJA publishes scientific papers which contribute to understanding of the geology of Slovenia or to general understanding of all fields of geology. Some shorter contributions on technical or conceptual issues are also welcome. Occasionally, a collection of symposia papers is also published. All submitted manuscripts are peer-reviewed. When submitting paper, authors should recommend at least three reviewers. Note that the editorial office retains the sole right to decide whether or not the suggested reviewers are used. Authors should correct their papers according to the instructions given by the reviewers. Should you disagree with any part of the reviews, please explain why. Revised manuscript will be reconsidered for publication. Author’s declaration: Submission of a paper for publication in GEOLOGIJA implies that the work described has not been published previously, that it is not under consideration for publication elsewhere and that, if accepted, it will not be published elsewhere. Authors agree that their contributions published in GEOLOGIJA are open access under the licence CC-BY. Language: Papers should be written in English or Slovene, and should have both English and Slovene abstracts. Types of papers: Original scientific paper In an original scientific paper, original research results are published for the first time and in such a form that the research can be repeated and the results checked. It should be organised according to the IMRAD scheme (Introduction, Methods, Results, And Discussion). Review scientific paper In a review scientific paper the newest published works on specific research field or works of a single researcher or a group of researchers are presented in order to summarise, analyse, evaluate or synthesise previously published information. However, it should contain new information and/or new interpretations. Professional paper Technical papers give information on research results that have already been published and emphasise their applicability. Discussion paper A discussion gives an evaluation of another paper, or parts of it, published in GEOLOGIJA or discusses its ideas. Book review This is a contribution that presents a content of a new book in the field of geology. Style guide: Submitted manuscripts should not exceed 20 pages of A4 format including figures, tables and plates. Only exceptionally and in agreement with the editorial board longer contributions can also be accepted. Manuscripts submitted to the editorial office should include figures, tables and plates in electronic format organized according to the following scheme: - Title (maximum 12 words) - Authors (full name and family name, postal address and e-mail address) - Key words (maximum 7 words) - Abstract (maximum 300 words) - Text - References - Figure and Table Captions - Tables, Figures, Plates References: References should be cited in the text as follows: (Flügel, 2004) for a single author, (Plenicar & Buser, 1967) for two authors and (Mlakar et al., 1992) for multiple authors. Pages and figures should be cited as follows: (Plenicar, 1993, p. 67) and (Plenicar, 1993, fig. 1). Anonymous internet resources should be cited as (Internet 1). Only published references should be cited. Manuscripts should be cited only in some special cases in which it also has to be stated where they are kept. Cited reference list should include only publications that are mentioned in the paper. Authors should be listed alphabetically. Journal titles should be given in a standard abbreviated form. A DOI identifier, if there is any, should be placed at the end as shown in the first case below. Taxonomic names should be in italics, while names of the authors of taxonomic names should be in normal, such as Clypeaster pyramidalis Michelin, Galeanella tollmanni (Kristan), Echinoidea. Articles should be listed as follows: Mali, N., Urbanc, J. & Leis, A. 2007: Tracing of water movement through the unsaturated zone of a coarse gravel aquifer by means of dye and deuterated water. Environ. geol., 51/8: 1401–1412. https://doi.org/10.1007/s00254-006-0437-4 Plenicar, M. 1993: Apricardia pachiniana Sirna from lower part of Liburnian beds at Divaca (Triest-Komen Plateau). Geologija, 35: 65–68. Books should be listed as follows: Flel, E. 2004: Mikrofacies of Carbonate Rocks. Springer Verlag, Berlin: 976 p.Jurkovšek, B., Toman, M., Ogorelec, B., Šribar, L., Drobne,K., Poljak, M. & Šribar, Lj. 1996: Formacijska geološka karta južnega dela Tržaško-komenske planote – Kredne in paleogenske kamnine 1: 50.000 = Geological map of the southern part of the Trieste-Komen plateau – Cretaceous and Paleogene carbonate rocks. Geološki zavod Slovenije, Ljubljana: 143 p., incl. Pls. 23, 1 geol. map. Book chapters should be listed as follows: Turnšek, D. & Drobne, K. 1998: Paleocene corals from the northern Adriatic platform. In: Hottinger, L. & Drobne, K. (eds.): Paleogene Shallow Benthos of the Tethys. Dela SAZU, IV. Razreda, 34/2: 129–154, incl. 10 Pls. Internet sources should be listed as follows: Known author and title: Carman, M. 2009: Priporocila lastnikom objektov, zgrajenih na nestabilnih obmocjih. Internet: http://www.geo-zs. si/UserFiles/1/File/Nasveti_lastnikom_objektov_na_ nestabilnih_tleh.pdf (17. 1. 2010) Unknown authors and title: Internet: http://www.geo-zs.si/ (22.10.2009) When more than one unit from the internet are cited they should be numbered: Internet 1: http://www.geo-zs.si/ (15.11. 2000) Internet 2: http://www.geo-zs.si/ (10.12. 2009) Figures, tables and plates: Figures (illustrations and photographs), tables and plates should be numbered consecutively and marked as Fig. 1, Fig. 2 etc., and saved as TIFF, JPG, EPS or PDF files and submitted at 300 dpi. Colour pictures will be published only on the basis of previous agreement with the editorial office. If, together with the article, you submit colour figures then these figures will appear in colour only in the Website version of the article. Be careful that the grey scale printed version is also readable. Graphic materials should be adapted to the journal’s format. They should be up to 172 mm (one page) or 83 mm wide (half page, one column), and up to 235 mm high. Larger formats can only be printed as a double-sided illustration (left and right) with a cut in the middle. All graphic materials should be referred to in the text and numbered in the sequence in which they are cited. The approval for using illustrations previously published in other journals or books should be obtained by each author. When a paper is written in Slovene it has to have the entire text which accompanies illustrations and tables written both in Slovene and English. Figure and table captions should be kept as short as possible. Proofs: Proofs (in pdf format) will be sent by e-mail to the corresponding author. Corrections are made by the authors. They should correct only typographical errors. Short additions and changes are possible, but they will be charged to the authors. GEOLOGIJA is an open access journal; all pdfs can be downloaded from the website: http://www.geologija-revija.si/ en/ Submission: Authors should submit their papers in electronic form to the address of the GEOLOGIJA editorial office: GEOLOGIJA Geological Survey of Slovenia Dimi~eva ulica 14, SI-1000 Ljubljana, Slovenia bernarda.bole.geo-zs.si or urednik.geologija-revija.si The Editorial Office GEOLOGIJA št.: 62/2, 2019 www.geologija-revija.si Gale, L., Kolar-Jurkovšek, T., Karnicnik, B., Celarc, B., Gorican, Š. & Rožic, B. 153 Triassic deep water sedimentation in the Bled Basin, eastern Julian Alps, Slovenia Miler, M., Mašera, T., Zupancic, N. & Jarc, S. 175 Characteristics of minerals in Slovenian marbles Mencin Gale, E., Jamšek Rupnik, P., Trajanova, M., Gale, L., Bavec, M., Anselmetti, F. S. & Šmuc, A. 189 Provenance and morphostratigraphy of the Pliocene Quaternary sediments in the Celje and Drava-Ptuj Basins (eastern Slovenia) Kanduc, T., Verbovšek, T., Novak, R. & Jacimovic, R. 219 Multielemental composition of some Slovenian coals determined with k0-INAA method and comparison with ICP-MS methods Koren, K. & Janža, M. 237 Risk assessment for open loop geothermal systems, in relation to groundwater chemical composition (Ljubljana pilot area, Slovenia) Adrinek, S. & Brencic, M. 251 Statistical analysis of groundwater drought on Dravsko-Ptujsko polje Uhan, J. & Andjelov, M. 267 Ocena doseganja trajnostnih ciljev z vidika upravljanja in varovanja podzemnih voda v Sloveniji Ceru, T. & Gosar, A. 279 Pregled uporabe georadarja na krasu Koroša, A. & Mali, N. 301 Razširjenost pesticidov v vodonosniku Dravskega polja ISSN 0016-7789