GEOLOGIJA 41, 223-255 (1998), Ljubljana 1999
Contribution to the macrotectonic subdivision of the border
region between Southern Alps and External Dinarides
Prispevek k makrotektonski rajonizaciji mejnega ozemlja med
Južnimi Alpami in Zunanjimi Dinaridi
Ladislav Placer
Geološki zavod Slovenije,
Dimičeva 14, 1000 Ljubljana, Slovenija
Key words: tectonics, Eastern Alps, Southern Alps, External Dinarides, Slovenia
Ključne besede: tektonika, Vzhodne Alpe, Južne Alpe, Zunanji Dinaridi, Slovenija
Abstract
In the paper the bases for macrotectonic dismembering of the border region bet-
ween the Southern Alps and the External Dinarides are given. The gravity point lies
on problems of establishing the course of the Southalpine thrust border, or the Sou-
thalpine front west and east of the Ljubljana basin, and the relationship of the nap-
pe units of the External Dinarides to this border.
North of the Periadriatic lineament lie the Eastern Alps. South of the Periadria-
tic lineament extend the Dinarides that are subdivided into Southern Alps and Ex-
ternal and Internal Dinarides. The Southern Alps lie between the Periadriatic linea-
ment and the Southalpine front. A special position in the Southern Alps has the Pe-
riadriatic tectonic zone between the Periadriatic lineament and the Sava fault. The
Southern Alps are thrusted on the External Dinarides and the Adriatic or Apulian
foreland. Both units are declined with respect to the Southern Alps for 30-45° Ex-
ternal Dinaric front is forming the border between the Adriatic or Apulian foreland
and External Dinarides, and between the External and Internal Dinarides exists a
transitional area that is characterized as the domain of migration of the southwe-
stern border of the pelagic development of the Internal Dinarides during the Meso-
zoic. The Pannonian basin consists of terrains that were formed from parts of the
megastructural units of Alps and Dinarides. The Southalpine front passes east of
the Ljubljana basin into the Mid-Transdanubian zone.
Kratka vsebina
V članku so podane osnove makrotektonske rajonizacije ozemlja na meji med
Južnimi Alpami in Zunanjimi Dinaridi. Težišče članka je razprava o problemih do-
ločitve trase Južnoalpske narivne meje ali Južnoalpske meje zahodno in vzhodno od
Ljubljanske kotline in odnos krovnih enot Zunanjih Dinaridov do te meje.
Severno od Periadriatskega lineamenta so Vzhodne Alpe. Južno od Periadriat-
skega lineamenta so Dinaridi, ki jih delimo na Južne Alpe ter Zunanje in Notranje
Dinaride. Južne Alpe ležijo med Periadriatskim lineamentom in Južnoalpsko mejo.
Posebno mesto v Južnih Alpah ima Periadriatska tektonska cona med Periadriat-
224_Ladislav Placer
skim lineamentom in Savskim prelomom. Južne Alpe so narinjene na Zunanje Di-
naride in Jadransko ali Apulijsko predgorje. Obe enoti sta nasproti Južnim Alpam
zamaknjeni za 30o-45o. Mejo med Jadranskim ali Apulijskim predgorjem in Zuna-
njimi Dinaridi tvori Zunanjedinarska meja, med Zunanjimi in Notranjimi Dinaridi
pa obstaja prehodno območje, ki označuje predel migracije jugozahodne meje pela-
gičnega razvoja Notranjih Dinaridov tekom mezozoika. Panonski bazen je sestav-
ljen iz terranov, ki so nastali iz delov megastrukturnih enot Alp in Dinaridov.
Južnoalpska meja se vzhodno od Ljubljanske kotline nadaljuje v Srednjetransdanu-
bijsko cono.
Introduction
The formal geotectonic subdivision of the territory on the contact of Eastern Alps
and Dinarides into the Eastern Alps, Southern Alps, External and Internal Dinari-
des, Adriatic or Apulian foreland and the Pannonian basin (fig. 1) was built up gra-
dually by generations of geologists starting with the famous K o s s m a t's (1913) tre-
atise on the folded hinterland of the Adriatic Sea. The boundary between the Eastern
and the Southern Alps is not questionable since it passes along the Periadriatic linea-
ment and the Ljutomer fault as the probable extension of the Balaton lineament.
Both terms signify the same disjunctive unit that is cut by the Labot (Lavanttal) fa-
ult. Also the Pannonian subsidence does not represent an unsolvable problem altho-
ugh its limits cannot be clearly defined. Out of the embarassment helps the distribu-
tion of the Tertiary sedimentary beds; therefore the term Pannonian basin is applied.
Serious troubles arise, however, when we try to delimit the Southern Alps from the
External and Internal Dinarides, and to separate the latter two units. The proposal
for tectonic subdivision shown in fig. 1 was made by using the data of the Basic geo-
logic map of Yugoslavia 1:100,000, B u s e r's Geologic map of Slovenia 1:250,000, in
print, Geologic map of Slovenia 1:500,000 (Buser & Draksler, 1993), and the
results of recent investigations, as listed in the contents.
The methodology for the proposed tectonic dismembering is based on the nappe
structure of the Southern Alps and External Dinarides, on tectonic elements of vario-
us hierarchic levels, and on sedimentologic criteria. The nappe structure of the Sou-
thern Alps and External Dinarides is derived from the detachment plane between
competent Mesozoic, mostly carbonate rocks, and incompetent Paleozoic clastic
rocks. The latter act as a soft bed to the nappe units. The detachment plane was reco-
gnized in the Sava folds and in the Upper Savinja valley in the area of Podolševa. A
first order tectonic element is considered the Periadriatic lineament that separates
the Eastern Alps from the Dinarides and the faults bounding the Tisa unit east of the
Zagreb from the Dinarides. A second order tectonic element is the Southalpine thrust
border between the Southern Alps and the External Dinarides. This line was formed
within the originally unique sedimentation domain. The third order tectonic elements
are considered the Sava and Idrija fault and the borders of extended nappe units wi-
thin the Southern Alps and External Dinarides. The Dinaric directed faults NW-SE,
faults of the middlehungarian direction WSW-ENE and the external dinaric border
between the External Dinarides and the Adriatic, or Apulian foreland are termed the
fourth order tectonic elements. The boundary between the External and the Internal
Dinarides is depositional, and such is also the border of the Pannonian basin.
Contribution to the macrotectonic subdivision_225
Boundary between the Southern Alps and the External Dinarides
In the present work especially the boundary between the Southern Alps and the
External Dinarides will be discussed.
Only with the mapping for the Basic geologic map of Yugoslavia 1:100,000 an un-
disputed opinion on the attribution of the Blegos Mountain as part of the Poljane-Vr-
hnika range to the External Dinarides (Grad & Ferjancic, 1974, 1976;
P r e m r u , 1980) could be established. This concept was confirmed also by kinema-
tic analysis of genesis of the Blegos structure (Placer & Car, 1997) from which it
follows that Blegos was formed first by overthrusts of dinaric orientation NE-SW,
and then by extensive overthrusting of the Southern Alps from north to south. Conse-
quently, in the Blegos area the structural boundary between the Southern Alps and
the External Dinarides can be quite unequivocally defined, since it follows a thrust
plane. This boundary is, next to the Periadriatic lineament, the most important dislo-
cation of the considered region. Its course west of Blegos is relatively clearly defined:
in the north of it extend the deeper marine deposits of the Slovenian basin, and on
the southern side the carbonate beds of the Trnovo nappe. The lithologic difference of
the two units is distinctly visible in the area of Blegos westwards to Tolmin. West of
there the boundary can be followed according to structural criteria, as here are come
in contact similar rocks of the two mentioned units. This boundary was defined by
Kossmat (1913) already as the line Kobarid-Stol-Cerkno, and more in detail by
B u s e r (1986, 1987) on the sheet Tolmin and Udine (Videm). A special meaning for
proving the overthrust character of this boundary have the Ponikve and Senica tecto-
nic klippes at Tolmin. The further westward continuation of the considered thrust
plane is resumed from S 1 e j k o et al. (1986) who has drawn it to the recent tectonic
graben in the Tagliamento valley between Gemona (Gumin) and Moggio Udinese
(Muzac), and farther southwest wards. For this boundary they proposed the term Sou-
thalpine front. C a r u 11 i et al. (1990) proposed the term Periadriatic overthrust. In
this paper the older variant is used since it is more distinct.
Eastwards the Southalpine front can be followed to Kranj from where it turns
sharply towards south-southwest to east of Skofja Loka, and then eastwards to Me-
dvode along the western rim of the Ljubljana basin. Here start difficulties that need
some more extended explanations. To understand the problem properly, the Trnovo
nappe which is a part of the External Dinarides, and its relationship to Southern
Alps and to the Sava folds should be considered first. The Sava folds extend, accor-
ding to the new definition (Placer, 1998, this journal), east of the Ljubljana basin
only, while west of it they do not exist in the structural sense. The Trnovo nappe com-
prises the Trnovski gozd with Banjsice, Idrija-Ziri region and Skofja Loka-Polhov
Gradec region. It is overthrusted from NE to SW on the Hrusica nappe, whereas from
north southwards the Southern Alps are overthrusted on it along the just discussed
Southalpine front. It follows from the internal structure of the Trnovo nappe
(M 1 a k a r, 1969; Placer, 1973, 1981) that its thrust plane forms an oblique section
in the manner that the youngest rocks are developed in the ovethrusting direction in
the thrust front above the Vipava valley, where Cretaceous and Paleocene beds occur,
and the oldest Carboniferous-Permian elastics in the root of the nappe in the Skofja
Loka-Polhov Gradec region. In the latter instance, they are overthrusted on the Tri-
assic rocks of the Poljane-Vrhnika ranges that are in the larger sense a part of the
Mesozoic beds of southern Slovenia, and in the narrower sense a part of the Hrusica
nappe. In contrast to that lie the Carboniferous-Permian rocks of the Litija anticline
226 Ladislav Placer
Contribution to the macrotectonic subdivision 227
228_Ladislav Placer
Fig. 1. Sketch of macrotectonic subdivision the bordering region between Southern Alps and
External Dinarides
1 Region of the metamorphic rocks; 2 Northern Karavanke Mountains (Drava range); 3 Regions
of the periadriatic igneous rocks; 4 Košuta unit; 5 Javornik unit; 6 Julian nappe, a - Zlatna
structure; 7 „Tolmin nappe", a - Supposed Slovenian basin, P - Ponikve tectonic klippe, T.K. -
Preveški hrib tectonic klippe; 8 In tectonical sense undefined region; 9 Trnovo nappe, a - Škofja
Loka-Polhov Gradec horses; 10 H - Hrušica nappe, S -Snežnik thrust sheet, K - Komen thrust
sheet, I - Kras imbricate structure, a - Pseudozilja beds in the Blegoš region; 11 Autochthon -
Istria (Adriatic or Apulian foreland), Pc - Paleocene, E - Eocene; 12 Deeper water sedimentary
rocks of Dinaric platform in the Trnovo nappe, K2 - Upper Cretaceous, Pc - Paleocene; 13 Paleo-
gene of External Dinarides, Pc - Paleocene, E - Eocene; 14 Upper Triassic, Jurassic and Cretace-
ous pelagic sediments of the transitional region between External and Internal Dinarides; 15
Tertiary and Plioquaternary of the Pannonian basin and marginal depressions; 16 Quaternary;
17 Paleozoic, soft bed of the nappe structure of the Dinarides, isostatic and supplantic uplifted
region, a - In Southern Alps, b - In External Dinarides; 18 Periadriatic and Balaton lineaments;
19 Important fault; 20 Southalpine front; 21 Overthrust boundary in the Southern Alps region;
22 Detachment plane of the Southalpine overthrust structure; 23 Trnovo nappe boundary; 24
Nappe and overthrust boundary in the External Dinarides region; 25 Detachment plane of the
External Dinarides overthrust and nappe structure; 26 Overthrust boundary in the North Kara-
vanke Mountains unit; 27 Thrust boundary of local importance in the Sava compressive wedge;
28 Inaccurately defined or covered fault and thrust line; 29 Hypothetic fault and thrust line or
fault and thrust zone; 30 Direction of overthrusting; 31 Eastern Alps; 32 Dinarides, a -Southern
Alps, b -External Dinarides, c - Transitional region between External and Internal Dinarides;
33 Adriatic or Apulian foreland; 34 Pannonian basin
SI. 1. Skica makrotektonske rajonizacije mejnega ozemlja med Južnimi Alpami in Zunanjimi
Dinaridi
1 Območje metamorfnih kamnin; 2 Severne Karavanke (Dravski niz); 3 Območja periadriatskih
magmatskih kamnin; 4 Košutina enota; 5 Javorniška enota; 6 Julijski pokrov, a - Zlatenska
plošča; 7 „Tolminski pokrov", a - Slovenski bazen, P. - Ponikvanska tektonska krpa, T.K. - Pre-
veška tektonska krpa; 8 V narivnem smislu neopredeljeno območje; 9 Trnovski pokrov, a - Ško-
fjeloško-Polhograjske luske; 10 H - Hrušiški pokrov, S - Snežniška narivna gruda, K - Komen-
ska narivna gruda, I - Kraški naluskani prag, a - Psevdoziljske plasti na območju Blegoša; 11
Avtohton - Istra (Jadransko ali Apulijsko predgorje), Pc - paleocen, E - eocen; 12 Globljevodne
kamnine Dinarske platforme v Trnovskem pokrovu, K2 -zgornja kreda, Pc - paleocen; 13 Paleo-
gen Zunanjih Dinaridov, Pc - paleocen, E - eocen; 14 Zgornjetriasni, jurski in kredni pelagični
sedimenti prehodnega območja med Zunanjimi in Notranjimi Dinaridi; 15 Terciar in pliokvar-
tar Panonskega bazena in obrobnih depresij; 16 Kvartar; 17 Paleozoik, mehka posteljica krovne
zgradbe Dinaridov, izostatično in izrivno dvignjeno območje, a - V Južnih Alpah, b - V Zunanjih
Dinaridih; 18 Periadriatski in Balatonski lineament; 19 Pomemben prelom; 20 Južnoalpska me-
jaki Meja pokrova v Južnih Alpah; 22 Ločilna ploskev Južnih Alp; 23 Meja Trnovskega pokro-
va; 24 Meja pokrova in narivne grude v Zunanjih Dinaridih; 25 Ločilna ploskev Zunanjih Dina-
ridov; 26 Narivna meja v Severnih Karavankah; 27 Nariv krajevnega pomena znotraj Savskega
kompresijskega klina; 28 Nenatančno določena ali prekrita prelomnica in narivnica; 29 Hipote-
tična prelomnica in narivnica ali prelomna in narivna cona; 30 Smer krovnega narivanja; 31
Vzhodne Alpe; 32 Dinaridi, a - Južne Alpe, b -Zunanji Dinaridi, c - Prehodno območje med Zu-
nanjimi in Notranji Dinaridi; 33 Jadransko ali Apulijsko predgorje; 34 Panonski bazen
Contribution to the macrotectonic subdivision 229
south and east of the Ljubljana basin consistently below the Mesozoic rocks of sou-
thern Slovenia, and so without a single direct of indirect indication for a different
position. This anomaly was noticed by K o s m a t (1913) already, and he solved it by
limiting the overthrust of the Skofja Loka-Polhov Gradec region, which he did not
compare to the Trnovski gozd nappe, to the domain of Poljane-Vrhnika ranges, Lju-
bljana Moor and Golovec south of Ljubljana. This concept was adopted from him by
Winkler (1923) and R a k o v e c (1956). A new solution was proposed by M i o c
(1976, 1981) with his idea of the Sava nappe that should comprise the Idrija-Ziri and
Skofja Loka-Polhov Gradec regions and Carboniferous-Permian and Mesozoic beds
of the Sava folds, and that should have been thrusted southwards on the Mesozoic
beds of southern Slovenia. That the Carboniferous-Permian beds of the Litija anticli-
ne were overthrusted southwards was believed also by P r e m r u (1980, 1983a,
1983b) and M 1 a k a r (1987) as well as by the authors of the Structural model of Italy
(B i g i et al., 1990). In contrast did B u s e r (1978, 1979), similarly to Kossmat, Win-
kler ad Rakovec, consider that the Carboniferous-Permian beds of the Litija anticli-
ne underlie the Mesozoic beds of southern Slovenia. With our pilot investigations we
came to the same conclusion as Buser.
sw ne
Fig. 2. Idealized section through the nappe structure of northwestern part of the External Dina
rides (Modified after P 1 a c e r, 1981, fig. 7)
1 Eocene flysch; 2 Carborniferous-Permian beds; 3 Thrust plane in External Dinarides; 4 Sou-
thalpine front; 5 Detachment plane; A Autochthon - Istria (Adriatic or Apulian foreland); I Kras
imbricate structure, Thrust front of the External Dinarides; K Komen thrust sheet; S Snežnik
thrust sheet; H Hrušica nappe; T Trnovo nappe
S1. 2. Idealiziran profil krovne zgradbe severozahodnega dela Zunanjih Dinaridov (Prirejeno po
Pl a c e r j u, 1981, si. 7)
1 Eocenski fliš; 2 Karbonskopermske plasti; 3 Narivna ploskev v Zunanjih Dinaridih; 4 Južno-
alpska meja; 5 Ločilna ploskev; A Avtohton - Istra (Jadransko ali Apulijsko predgorje); I Kraški
naluskani prag, Narivno čelo Zunanjih Dinaridov; K Komenska narivna gruda; S Snežniška na-
rivna gruda; H Hrušiški pokrov; T Trnovski pokrov
230 Ladislav Placer
It follows from the position of the Carbonoferous-Permian beds west and east of
the Ljubljana basin that these beds in central Slovenia take part of two distinct tec-
tonic units. Those in the west belong to the Trnovo nappe, and those in the east lie
below the Mesozoic beds of south Slovenia, i.e. below the Hrusica nappe and the
thrusted units east of it. In order to understand the problem of structure of central
Slovenia in the sense of this concept, we should take a closer look at the nappe struc-
ture of southwest Slovenia (Placer, 1981, fig. 7a) that is shown in a simplified ver-
sion in fig. 2 and 3.
It follows from the relationship between the Trnovo and Hrusica nappes, fig. 2a,
that the Carboniferous-Permian beds of the Trnovo nappe in the northeast part of the
cross-section overlie analogous beds of the Hrusica nappe. Since the cross-section
has been constructed from data on the position, internal sructure, thickness and
length of nappe units and overthrust distance, the conclusion can be reached, as in
Fig. 3. Relationship between the Trnovo nappe and the Southalpine front
1 Southalpine front; 2 Trnovo nappe boundary; 3 Hrusica nappe and Snežnik thrust sheet boun-
dary; 4 Detachment plane in External Dinarides; 5 Direction of overthrusting; 6 Border of ac-
companying deformations at the Southalpine front; T Trnovo nappe; H Hrušica nappe; S
Snežnik thrust sheet.
SI. 3. Razmerje med Trnovskim pokrovom in Južnoalpsko mejo
1 Južnoalpska meja; 2 Meja Trnovskega pokrova; 3 Meja Hrušiškega pokrova in Snežniške na-
rivne grude; 4 Ločilna ploskev v Zunanjih Dinaridih; 5 Smer krovnega narivanja; 6 Meja sprem-
ljajočih deformacij ob Južnoalpski meji; T Trnovski pokrov; H Hrušiški pokrov; S Snežniška na-
rivna gruda.
Contribution to the macrotectonic subdivision 231
the former alinea, that the Carboniferous-Permian beds of the Skofja Loka-Polhov
Gradec region overlie the Mesozoic rocks of south Slovenia as well as the Carbonife-
rous-Permian beds of the Litija anticline east of the Ljubljana basin. These lie consi-
stently below the carbonate sedimentary nappe of southern Slovenia. Since we dedu-
ce the nappe structure of the External Dinarides from a unique detachment plane, it
is possible to conclude the very complicated shape of this plane that forms the boun-
dary between the Carboniferous-Permian of the Litija anticline that in places include
also the Val Gardena beds, and east of Kum also the Werfenian and Middle Triassic
beds, and the Mesozoic beds. Therefore it is entirely understandable that in the Sava
folds the younger beds are overthrusted on older ones, as for the detachment plane
the parallel, and not the oblique section is characteristic. This peculiarity has been
often used as the basis for an argument against the nappe, or overthrust structure of
this part of Slovenia. The detachment plane passes also within the Carboniferous-
Permian beds. Therefore its position on the border between the Paleozoic and Meso-
zoic beds in the Sava folds in fig. 1 is largely formal.
The southeastern border of the Trnovo nappe has a transversal-dinaric direction
SW-NE. In the treatise on the structure of southwestern Slovenia (Placer, 1981)
this was proved by dip of axes of large overthrust folds in the nappe front towards
southwest. However, this fact is not a sufficient reason for the anomalous direction of
Fig. 4. Two histograms of different types of thrust range in External Dinarides, a - exponential
thrust range, section in fig. 2a and section 1-1 in fig. 3, b - combined thrust range, section in
fig. 2b and section 2-2 in the fig. 3
I Karst imbricate threshold; K Komen thrust sheet; S Snežnik thrust sheet; H Hrušica nappe; T
Trnovo nappe; N Thrust unit in hinterland of Hrušica nappe
S1. 4. Dva histograma različnih tipov narivnega niza v Zunanjih Dinaridih, a - eksponencialni
narivni niz, profil na si. 2a in profil 1-1 na si. 3, b - kombiniran narivni niz, profil na si. 2b in
profil 2-2 na si. 3
I Kraški naluskani prag; K Komenska narivna gruda; S Snežniška narivna gruda; H Hrušiški
pokrov; T Trnovski pokrov; N Narivna enota v zaledju Hrušiškega pokrova
232 Ladislav Placer
Fig. 5. Map of the Moho isobaths (After C a r u 11 i et al., 1990, fig. 3), 1-1 and 2-2 sections in
figs. 2 and 3
SI. 5. Karta Mohorovicicevih izobat (po Carulliju et al., 1990, si. 3), 1-1 in 2-2 profila na si.
2 in 3
the considered border, as in the Poljane-Vrhnika ranges the Trnovo nappe is not in-
clined towards northwest anymore, but the direction of the border does not change
accordingly. It is more likely that the southeast border of the Trnovo nappe represents
the lateral border of this large nappe unit the largest part of which is covered by the
Southern Alps. The situation is schematically shown in fig. 3 where for easier orien-
tation also the Poljane-Vrhnika ranges and Blegos are also drawn. The extent of the
Trnovo nappe and the extraordinary structure of Blegos are indications of the impor-
tance of the Southalpine front. Along it a large displacement is supposed that could
be explained by substantial rotation of the External Dinarides versus the Southern
Alps, or by overthrusting without rotation, as believed e.g. by P r e m r u (1980),
Doglioni & Siorpaes (1990) and Polinski & Eisbacher (1992).
As the Trnovo nappe is of limited extent, the model in fig. 2 and its kinematic-
dynamic derivation with an exponential thrust range (fig. 4a) could be valid only for
the cross-section that passes across the Trnovo nappe (cross-section 1-1 in fig. 3),
whereas the circumstances in cross-section 2-2 (fig. 3) beyond the Trnovo nappe in
Contribution to the macrotectonic subdivision 233
Fig. 6. Crustal cross-section between Gulf of Trieste and Ljubljana basin showing the nappe
structure. Legende in fig. 2.
SI. 6. Profil zemeljske skorje med Tržaškim zalivom in Ljubljansko kotlino z vidika krovne
zgradbe. Legenda na si. 2
fig. 2b and 3 are already different. Although the Trnovo nappe originally extended
somewhat farther southeast wards, and was later eroded, we consider its extent in
this direction not much different from the present one owing to the absence, throug-
hout south Slovenia, of tectonic klippes that would indicate the contrary. Therefore
the structure of the External Dinarides southeast of the Trnovo nappe should be de-
duced from the cross-section in fig. 2b, namely from the accumulation of nappe units
in the southwest, with the Hrusica nappe as the highest member, and in the northeast
as the separating thrust imbricated structure as established e.g. from a borehole at
Dolenjske Toplice (P r e m r u et al., 1977) where Jurassic beds are thrust over the
Cretaceous. We could hypothetically consider a nappe structure derived from the de-
tachment plane with an assumed combined thrust range (Placer, 1982) as shown in
fig. 4b.
From cross-section 1-1 in fig. 2 and 3 can further also be hypothesized that the ne-
gative anomaly of the Mohorovicic discontinuity at 45 km in fig. 5 (after C a r u 11 i
et al., 1990, fig. 3) in the relatively narrow space between the Trieste gulf and Lju-
bljana basin could be the consequence of isostatic subsidence of the territory on
which the nappe unit were stacked one above the other. The size of the anomaly in
the NW-SE direction corresponds to the position and size of the Trnovo nappe. The
map that was published by Carulli et al. was used by us owing to its better resoluti-
on with respect to the Structural map of Mohorovicic discontinuity for the territory
234_Ladislav Placer
of Yugoslavia (Dragasevic et al., 1989). On the contrast, in the root area of the
nappe units the isostatic uplift of the soft bed of incompetent Carboniferous-Permian
beds below the Mesozoic strata can be observed. The described relationship between
the nappe structure and the Mohorovicic discontinuity is illustrated by cross-section
in fig. 6 which is identical with cross-section 1-1, except for the fact that in its con-
struction the real situation from fig. 1 was taken in account but without the Idrija fa-
ult, since only the nappe structure is being considered here. The anomaly southeast of
the Trnovo nappe is here somewhat smaller (40 km), but it nevertheless clearly ex-
presses the isostatic subsidence of the overthrusted units, and the uplift in the region
of the Sava folds. The outcropping of Carboniferous-Permian beds in the Polhov
Gradec-Skofja Loka hills and in the area of the Sava folds has consequently a logic
explanation. The picture can be supplemented also by the uplift of the Sava folds wi-
thin the Sava compressive wedge (Placer, 1998, this journal).
From the discussed facts it can be concluded that the Carboniferous-Permian beds
of central Slovenia belong in their totality to the External Dinarides. This was belie-
ved already by B u s e r (1979).
In looking for the right answer about the course of the Southalpine front east of
Medvode, we are faced with a dilemma in spite of the solved question upon the attri-
bution of the Carboniferous-Permian beds to two structural units. This dilemma can-
not be adequately solved on the ground of the presently available data. Several que-
stions arise, the first considering the age of overthrusting, and the second one the in-
ternal structure of nappe units. The dinaric nappes are connected with the genesis of
Eocene flysch beds which would mean that the cycle of this overthrusting terminated
most likely at the end of the Eocene times. The southalpine nappes lie on the dinaric
nappes, so they could be only younger according to normal logic. In the Sava folds
the Mesozoic rocks take part in one or several large overthrust units that were over-
thrusted before the deposition of the Trbovlje beds (Placer, 1998, this journal; first
the Socka beds, and then the Pseudosocka beds - J e 1 e n et al., 1992) in Middle or
Late Oligocène. It would be therefore logical to compare one or several nappe units
that comprise the entire Sava folds with the dinaric nappes. However, in the facial
sense they are comparable only with rocks of the Slovenian basin and its rim west of
Skofja Loka and Kranj.
There is further the question of the age of the Julian nappe, as we named the nap-
pe of the Julian and the Kamnik-Savinja Alps. This nappe was named by G r a d &
Ferjancic (1976) the Jelovica nappe, by M i o c (1981) Julian - Savinja nappe, by
M i o c (1983) and P r e m r u (1983b) the Savinja overthrust, byJurkovsek
(1987b) the nappe of the Julian Alps, by B u s e r (1986) the Krn nappe, and by
K r y s t y n et al. (1994) in somewhat modified form the Krn, or the Pokljuka nappe.
In the present paper we accepted, regardless of the right of the first author, the name
proposed by Mioc, and we modified it to the term Julian nappe. It comprises the Juli-
an and the Kamnik-Savinja Alps. The age of the Julian nappe could be only indi-
rectly ascertained from the relation of the overthrust in the Julian Alps to the Oligo-
cène beds of the Ljubljana basin. These beds are exposed across its entire extent, and,
according to data of the Basic geologic map, sheets of Celovec (Buser & Cajhen,
1978) and Kranj (Grad & Ferjancic, 1974), below the Quaternary alluvial de-
posits the Ljubljana basin is covered almost completely with them. Therefore we co-
uld suppose Oligocène beds overlie also the thrust plane of the Julian nappe, if it
sinks below the Oligocène beds of the Ljubljana basin. The situation in the Kamnik-
Savinja Alps is at the first look different, however, and the interpretation with nap-
Contribution to the macrotectonic subdivision 235
Fig. 7. Position of Upper Triassic beds in western part of the Laško syncline
1 North limb; 2 Hinge; 3 South limb
SI. 7. Lega zgornjetriasnih plasti v zahodnem delu Laške sinklinale
1 Severno krilo; 2 Sedlo; 3 Južno krilo
pes thrusted on the Oligocène beds in sheet Celovec (Buser & Cajhen, 1978,
cross-section C-D) or sheet Ljubljana (P r e m r u, 1983a, cross-section A-B), is not
proved. Provable are only small overthrusts of post-Sarmatian, most probably post-
Middle Pliocene age that are the result of the compression within the Sava compres-
sive wedge and of the shortening of the area. Based on these data we believe that the
Kamnik-Savinja and the Julian Alps could have been overthrusted on the pelagic de-
posits of the Slovenian basin already before the Middle or Late Oligocène as one, or
possibly several nappe units in the Sava folds, and as it is valid also for the central
part of the Southern Alps (Doglioni & Bosellini, 1987). Between the end of
Eocene and the Middle to Late Oligocène there could be enough time for formation of
the Southalpine nappe structure. On the other side dis Buser (1980), P r e m r u
(1980) and Polinski & Eisbacher (1992) attribute the nappes of Juilian and
Kamnik-Savinja Alps to Neogene. The question is not simple. It could be solved only
by extensive research. The Oligocène beds at Bohinj, on Velika Planina and Kopišče
near Kamniška Bistrica river are of special importance for dating of the Julian nap-
pe. It should be noted, however, that separating the genesis of the Julian nappe from
the Southalpine front is not logical, and can be only a result of insufficient structural
factography on the region of the Julian and the Kamnik-Savinja Alps.
It was already stated with respect to the internal structure of the nappe units and
overthrusting directions that west of the Ljubljana basin the separation of the Dina-
ric and the Southalpine nappe structures can be made on the basis of dinaric (NW-
SE) and southalpine (W-E) structural elements. Therefore at the relatively short di-
stance east of the Ljubljana basin equal or at least similar situation could be expec-
ted. Yet, the structure there is different. Its dissimilarity is associated with the gene-
sis of the Sava folds within the Sava compressive wedge (Placer, 1998, this jour-
236 Ladislav Placer
nal): the Sava folds were intensely folded with axes in the W-E direction, and in this
process the dinaric nappe structures got externally effaced to a large degree. For de-
termining the course of the Southalpine front, the internal structure of the Mesozoic
beds in the Sava folds should be analyzed. Since up to the present only the wider area
of the Lasko syncline was mapped anew, the analysis of of dips of the thick bedded
Middle Triassic and Main Dolomite as well as the Dachstein Limestone was done only
Fig. 8. Course variants of the Southalpine front eastern of the Ljubljana basin
1 Southern Alps; 2 External Dinarides; 3 Tertiary; 4 Ljubljana basin and Ljubljana moor; Ex-
planation of other signs in the legend of fig. 1
SI. 8. Različici poteka Južnoalpske meje vzhodno od Ljubljanske kotline
1 Južne Alpe; 2 Zunanji Dinaridi; 3 Terciar; 4 Ljubljanska kotlina in Ljubljansko barje; Razlaga
ostalih znakov v legendi na si. 1
in this area. In thick bedded rocks the regional aspects of deformations are preserved
relatively independently of the local influences. These rocks occur west of the Kum
mountain. In the north limb of the Lasko syncline they are found at Reber above Ko-
lovrat northwest of Izlake and in the south limb between Kum and Slemsek above
Vace. In the southern limb of the syncline the beds dip generally toward west to west-
northwest, and in the northern limb towards southwest to south-southwest. It is possi-
ble to determine with a simple rotation around the W-E axis that is parallel to the axis
of folding that the poles of the beds of one and the other synclinal limbs lie in the sa-
me plane (fig. 7), while the constructed direction of the beds in the apex of the syncli-
ne is dinaric (NW-SE). Next to the structural aspect also the facial one is important.
Contribution to the macrotectonic subdivision_237
The characteristic condensed cross-section of Val Gardena and Bellerophon beds in
the highway cut at Višnja Gora (Skaberne, oral communication) was discovered also
in the Borovnik sand pit at Kisovec in the Laško syncline. This could suggest the same
depositional region. The position of the Upper Triassic beds and the development of
Permian beds could serve as an indication of the appurtenance of Mesozoic rocks in
the Sava folds, or at least those south of the Trojane anticline, to the External Dinari-
des. For confirmation of such conclusion the entire Sava folds must be analyzed. The-
refore to this observation no decisive importance could be attributed.
By considering the elements of age of the nappe thrusting and the internal structu-
re of the nappe units the clear answer about the passage of the course of the Southern
Alps east of the Ljubljana basin could not be approached. It was established, howe-
ver, that the nappe structure in the Sava folds is of pre-Middle to pre-Late Oligocene
age, that the Julian nappe is of the same, or of post-Sarmatian age, and that the Sou-
talpine front, along which the rocks of the Slovenian basin was thrusted southwards
west of the Ljubljana basin, is a temporal equivalent of the nappe strcuture of the
Sava folds; the Oligocene sedimentary beds at Medvode cover the Southalpine front.
From the said follow two variants of the passage of the Southalpine front east of the
Ljubljana basin. Each of them has its advantages and weaknesses. Both variants are
shown in fig. 8.
According to the variant 8a passes the border of the Southern Alps along the nor-
thern rim of the Carboniferous-Permian core of the Trojane anticline, and according
to variant in fig. 8b along the northern rim of the Carboniferous-Permian core of the
Litija anticline whereat also the Preveški hrib tectonic klippe (after the Preveški hrib
- hill above Polšnik, 873 m) belongs to the Southern Alps. According to the first vari-
ant the Upper Triassic, Jurassic and Cretaceous pelagic deposits of the Slovenian ba-
sin would belong to the Southern Alps, while the Triassic beds in the basement and
in limbs of the Laško syncline would belong to the highest nappe of the dinaric pro-
venience. This would be indicated also by the position of beds west of Kum. This va-
riant takes into account the strtuctural aspect of the position of beds and similarity
in development of condensed Val Gardena and Bellerophon beds at Kisovec and at
Višnja Gora, as well as the discordant position of Cretaceous deeper marine beds on
Triassic platform carbonate beds which is characteristic of the inner belt of the Ex-
ternal Dinarides. It must be borne in mind, however, that the position of beds only in
a small part of the Sava folds was analyzed, and that rather a gradual passage from
the predominant carbonate facies of Middle to Upper Triassic beds in the south to
clastic and pelagic development in the north, and not a radical tectonic discontinuity
is indicated by the development of the Mesozoic beds in this area, if the Southalpine
front would pass along the northern rim of the Trojane anticline. Therefore we took
at the present state of understanding for the working hypothesis the variant 8b
which is consistent with K o s s m a t's (1913) and W i n k 1 e r's (1923) understanding
of connection of the considered thrust plane between the western and the eastern
borders of the Ljubljana basin, but from different theoretic starting points.
Dilemmas connected with this question are more complex. They concern the for-
mational and structural problems (geometric and kinematic), paleomagnetism, pa-
linspastics, paleogeography and global tectonics. Thereof the need for complex ap-
proach to solving these problems in Slovenia is probably the most urgent, and should
be directly relied with the universal processing for the mapping of the geologic map
1:50,000. The vagueness is associated not only with the passage of the Southalpine
front east of the Ljubljana basin but also with the question of its global meaning.
238_Ladislav Placer
Discussion
Geotectonic subdivision of the territory of present Slovenia is based upon two me-
gadisjunctive features, the Periadriatic lineament and the Southalpine front as well
as on the internally heterogeneous and not very clearly delimited Pannonian sub-
sidence. Therefore it is simpler to talk of the Pannonian basin, although unfortuna-
telly in the term not only the geometry of the Pannonian subsidence is not reflected,
but also of the bordering territories with elements of the hereditary deformations
that are not genetically connected with the subsidence.
The aim of the present treatise is not detaiuled genetic subdivision, but moreover a
general formal tectonic subdivision of the Slovenian area and determination of the
most important tectonic units of regional importance, based upone global principles
and on nappe structure resulting from detachment tectonic geometry.
1. The Eastern Alps comprise region of the metamorphic rocks and regions of the
Mesozoic carbonate rocks (Drava range and other regions). Drava (Drau) range rea-
ches Slovenian territory as North Karavanke and their eastern relics at Mislinja and
Zrece.
2. The Dinarides are delimited from the Eastern Alps by the Periadriatic linea-
ment. They are commonly subdivided into the Southern Alps and the External and
Internal Dinarides.
2a. The Southern Alps lie between the Periadriatic lineament and the Southalpine
front. Their important structural unit is the Periadriatic tectonic zone (J e 1 e n et al.,
1997; Placer, 1998, this journal) between the Periadriatic lineament and the Sava
fault. In the present paper the question of the nappe structure of the Southern Alps is
not dealt with in any detail, but several general aspects are discussed that should be
the object of attention in the future. In spite of the shift along the Sava fault, let it be
25, 40 or 65 to 70 km (Placer, 1996b), the Julian and the Kamnik-Savinja Alps sho-
uld be considered as a single tectonic object in which the rocks of the Slovenian basin
occupy the central position. They occur, according to K r y s t y n et al. (1994), in the
Owing to insufficient state of investigation at present we cannot decide whether it
continues to the Mid-Transdanubian zone, or does it bend towards southeast. On the
ground of prevailing global views on the genesis of the Pannonian subsidence (e.g. C s
o n t o s et al., 1992; Horvath & Tari, 1998) in the present treatise the first vari-
ant, although it is only hypothetical, was used. We took orientation after the Mesozo-
ic ophiolitic melange of Kalnik and Medvednica that cannot be directly relied to the
deeper marine rocks of the Sava and Krsko hills and Gorjanci mountain, but we beli-
eve they belong in the broader sense to Internal Dinarides.
Here we should call attention to the opinion of P r e m r u (1980), Doglioni &
Siorpaes (1990) and Polinski & Eisbacher (1992) on the genesis of decli-
nation between the Southern Alps and External Dinarides, and hence follows that in
the Southern Alps relics of the dinaric oriented structural elements could be expec-
ted. Also therefore the choice of the 8b variant is at present more suitable.
Mentioned should be further the hypothesis by S 1 e j k o et al. (1986) and
C a r u 11 i et al. (1990) on the still active character of the Southalpine front west of
the Idrija fault. The concept is associated wtih the hereditary effects, and is an indi-
cation of the complexity of dating the disjunctive structures in areas in which several
tectonic phases occurred.
Contribution to the macrotectonic subdivision_239
Tolmin nappe that lies below the Julian nappe. With respect to the extension of the
latter it can be stated that it is overthrusted in the south on the rocks of the Sloveni-
an basin (Tolmin area, Baska grapa, Selce valley, Županje Njive near Kamnik, Črna
valley near Kamnik), while in the north, on sheet Ravne, it overlies the rocks of Lo-
wer to Middle Triassic age, possibly also Upper Triassic (M i o č, 1983; M i o č &
Ž n i d a r č i č , 1983). This leads to the idea that the rocks of the northern rim of the
Julian nappe form the basement, and in places also the lateral equivalent of the de-
posits of the Slovenian basin, and that they belong most probably to the Tolmin nap-
pe as well as the rocks of the Slovenian basin. Owing to the hypothetic character of
this concept we write the „Tolmin nappe" of such extent in quotation marks. On she-
et Ravne lies the Lower Triassic beds of the „Tolmin nappe" with tectonic contact on
Carboniferous elastics that represent the soft bed of the Southern Alps. This unit
comprises next to the Paleozoic beds on the sheets Celovec and Beljak with Pontebba
also the Lower and Middle Triassic beds. The thrust plane itself towards the „Tolmin
nappe", however, is most probably hidden within the same formation. The rocks that
could be attributed to the Paleozoic basement of the „Tolmin nappe" occur also south
of the Sava fault above Kranjska gora and Rateče (Jurkovšek, 1987a). Above
them are the Lower and Middle Triassic beds of the „Tolmin nappe" that exend ac-
cording to the geologic map of the Structural model of Italy (B i g i et al., 1990) in a
narrow belt along the southern side of the Fella (Bela) fault far westward. In the
Structural model the boundary of these beds with the Upper Triassic beds is normal.
We suppose, however, that here similar situation occurs as on the sheet Beljak with
Pontebba (Jurkovšek, 1987a, cross-sectioin A-B), and therefore we assume also
here the existence of the „Tolmin nappe", whereas the Paleozoic beds are exposed
only in the area of Kranjska gora and Rateče. To the „Tolmin nappe" belong also the
Mesozoic rocks of the Sava folds that were reduced by the decision about the course
of the Southalpine front along the northern rim of the Litija anticline to a single nap-
pe unit. This solution must be considered hypothetic, however.
The Paleozoic soft bed rocks of the Southern Karavanke and the Triassic Kara-
wanke belt rocks of the „Tolmin nappe" betwen Sava fault and Periadriatic linea-
ment did B u s e r (1980), M i o č (1983) and Jurkovšek (1987a) attribute to the
South Karavanke unit that ought to comprise also the Lower and Middle Triassic
beds. Owing to the importance of the Paleozoic basement we propose for it the term
Javornik unit after Javorniški Rovt above Jesenice.
With regard to the exposed starting points occur in the Southern Alps the Javornik
and the Košuta units, and the „Tolmin" and the Julian nappe. The Košuta unit is a
tectonic lens of Mesozoic rocks between the Periadriatic lineament and several faults
within the Periadriatic tectonic zone (B r e n č i č et al., 1995) that played during the
development of the latter various dynamic parts. The Javornik unit is the soft bed of
the Southern Alps. The „Tolmin nappe" and the Julian nappe are nappe units over-
thrusted generally from the north southwards on the External Dinarides. Boskovec,
Paski Kozjak, Konjiška gora, Boč and Ravna gora are structurally part of the Julian
Alps, and owing to their rock composition we tentatively attribute them to the „Tol-
min nappe". According to rocks the Košuta unit in the Karavanke mountains could
be a part od the Julian nappe that was intensely tectonically reworked within the Pe-
riadriatic zone. However, this was not taken into account in the dismembering sche-
me owing to our general starting points.
The Julian and the „Tolmin" nappes are in the direction W-E dish-like deformed
which might be connected with the regional compression. The border between the Ja-
240_Ladislav Placer
vornik unit and the „Tolmin nappe" could be identical with the plane of the Southal-
pine front. The Southalpine overthrust border is at the same time the southern border
of the „Tolmin nappe".
2b. The External Dinarides are declined with regard to the Southern Alps for 30 to
45° and underthrusted below them. They consist of three belts: a - the external para-
autochthonous belt with preserved Tertiary sedimentary rocks in cores of synform
structures (the Kras imbricate structure, the Komen thrust sheet), b - the central al-
lochthonous part in which the Tertiary sedimentary beds are only exceptionally pre-
served (Snežnik, Hrušica, Trnovo nappes and the not yet subdivided thrust structure
northeast of the Hrušica nappe), and c - of the internal allochthonous belt represen-
ting the transition region between the External and the Internal Dinarides, or the so
called slope zone (Pleničar & Premru, 1975) that by some authors is consi-
dered as the Internal Dinarides. Is characterized by the migration of pelagial through
the Upper Triassic, Jurassic and Cretaceous. A special position in the External Dina-
rides is occupied by the Trnovo nappe which is only the extreme southeast visible
part of a larger nappe that is underthrusted below the Southern Alps. Exceptional
are its position and structure, since at its northwestern rim the degradation of the Di-
naric carbonate platform was started in the Upper Cretaceous already. Since the de-
gradation appeared in the Trnovo nappe first, we believe this observation to be one of
the more important data for the study of palinspastics of the Dinarides. In fig. 1 are
drawn next to the Trnovo nappe also the thrust borders of the Hrušica nappe,
Snežnik and Komen thrust sheets and the Kras imbricated structure, as the Ćićarija
imbricated structure was more adequately named by us (P 1 a c e r, 1981). The latter
occupies the part of thrust front for the External Dinarides. The boundaries of the
overthrust units of the northeastern part of the External Dinarides are not drawn
since their courses have not been analytically studied yet.
The Carboniferous-Permian beds in the Sava folds are a part of the External Di-
narides.
2c. The transition region between the External and the Internal Dinarides. On the
territory of Slovenia, in the megatectonic sense the Internal Dinarides are absent.
There remains only the transition region between the External and the Internal Di-
narides where the Jurassic and Cretaceous pelagial sediments were deposited discor-
dantly on Triassic and older rocks of the External Dinarides, or where the Upper Tri-
assic shelf gradually passes into the pelagial (Ogorelec & Dozet, 1997) where-
fore some authors consider this transitional region as Internal Dinarides. In the regi-
on of the Sava folds the transition region between the External and the Internal Di-
narides is underthrusted below similar rocks of the Slovenian basin or of the Sou-
thern Alps. The question on the appurtenance of the basement of deep sea deposits of
Medvednica and Kalnik remains open. It most probably belongs to a distinct structu-
ral unit within the Mid-Hungarian tectonic zone, and therefore it was not tectoni-
cally considered here. Similar difficulties are connected also with the southern slope
of Ivančica, if the hypothetic Southalpine front in this area is correctly placed.
3. The Adriatic or Apulian foreland is an autochthone of the dinaric thrust and
nappe structure. It is underthrusted together with the External Dinarides below the
Southern Alps.
4. The Pannonian basin is a heterogenous tectonic unit. Its basement consists of
the eastern, or better the east-northeastern extensions of the eastern alpine and dina-
ric geotectonic units that occur subsided under the Tertiary sedimentary beds of
Paratethys. After Haas et al. (1995) these units form extensive central alpine terra-
Contribution to the macrotectonic subdivision_241
nes that consist prevailingly of continental crust: the Easternalpine of metamorphic
rocks, Transdanubian of rocks of the Drava range or the Northern Karawanke moun-
tains, Mid-Transdanubian of rocks of Southern Alps, and the Tisza terrane consisting
of the rocks with European faunistic elements. It follows from the interpretation of
the Transdanubian and Mid-Transdanubian terranes that the boundary between
them is formed by the Balaton lineament which is a continuation of the Periadriatic
lineament east of the Labot (Lavanttal) fault. In the territory of Slovenia the Balaton
lineament is marked as the Ljutomer fault. The boundary between the Transdanubi-
an and the Eastern Alpine terrane is represented by the Raba fault (Haas et al.,
1995; Horvath & Tari, 1998) that should have been also the source structure of
the North Karavanke overthrust. On the map in fig. 1 the Raba fault is not drawn be-
cause of the uncertainty of its course in the considered teritory on the Basic geologic
map (sheets Goricko and Leibnitz, Maribor, Cakovec and Rogatec).
The structure of the Periadriatic tectonic zone is reflected in distinct development
of the Tertiary beds north and south of this zone as well as within it (J e 1 e n et al.,
1992, 1997). This diversity is an expression of its tectogenesis that was studied in de-
tail by F o d o r et al. (1998).
Conclusions
The proposed scheme of macrotectonic dismembering has the character of a wor-
king hypothesis, and is presented as basis for discussion of tectonic structure of Slo-
venia. With it we tried to submit those elements of global and the overthrust tecto-
nics of the territory at the crossing of three megastructures that shed light on the pro-
posed scheme. The most important of them are as follows:
1. Paleozoic beds occur in structurally the most uplifted parts for which we sup-
plied kinematic and dynamic explanation: a - in the isostatically strongly uplifted ro-
ot of the Trnovo nappe, b - in the intensely compressed and extruded Periadriatic
tectonic zone, and c - in the isostatically uplifted Sava folds that were, the same as
the Periadriatic tectonic zone, in the framework of the Sava compressive wedge
uplifted above the neighboring structures.
2. The characteristic structure of the External Dinarides and extension of the Tr-
novo nappe are confirmed by the negative anomaly of the Mohorovicic discontinuity
at the mark of 45 km.
3. The importance of the Southalpine front becomes integrally evident only when
being considered in the broader circumadriatic region. Lying at the contact between
the Southern Alps and the External Dinarides this front can be traced according to
the position of the Trnovo nappe and the peculiar double overthrust structure of Ble-
gos.
4. Difficulties in determining the course of the Southalpine front east of the Lju-
bljana basin are connected with deformations within the Sava compressive wedge
and with structurally insufficient geologic coverage on the scale of 1:100,000.
The questions that remained open are important for the palinspastic reconstructi-
on of genesis of the Dinarides and the Pannonian basin. Such is for example 1. the
question of the course of the Southalpine front east of the Ljubljana basin. It is not
unimportant for the palinspastics of this region whether its course is bent at the nor-
thern rim of the Litija anticline towards east-northeast, or towards southeast. De-
pending upon this is, however, the final selection between the variants 8a or 8b (fig.
242_Ladislav Placer
8), or some other. 2. The question of the course of this border is important also for un-
derstanding of the role of Pseudozilja beds in the area of Blegoš in the Poljane-Vrhni-
ka ranges and in the northern flank of the Laško syncline in the Sava folds, which is
one of the enigmas of the border territory between the Southern Alps and the Exter-
nal Dinarides.
Finally remains the comparison between several interpretations of the structure of
Slovenian territory as they were made on the basis of mapping for the Basic geologic
map. Here especially Mioč's idea on the Sava nappe and the structure of the transiti-
on teritory between the Eastern and the Southern Alps are meant as well as Premru's
interpretation of central Slovenia, although this was already the object of discussion
(Placer, 1998, this journal). Since the subdivision scheme presented in this paper
has the working character no detailed analysis of differences shall be given. We shall
limit ourselves to starting points of individual hypotheses only that are essentially
different, as are different also the interpretations. Mioč introduced in his works two
novelties, the Sava nappe (Mioč, 1976, 1981) and the idea of a unique overthrust
structure of the Southern and Northern Karavanke (Mioč, 1986, 1997). We already
said of the Sava nappe that it should include the Paleozoic and Mesozoic beds of the
Sava folds and of the Škofja Loka-Polhov Gradec and Žiri regions. It should have
been thrusted southwards on the carbonate shelf of the External Dinarides. We also
wrote that the Carboniferous-Permian beds of the Škofja Loka-Polhov Gradec region
that overlie the Mesozoic beds of Inner and Lower Carniola, or of the so called carbo-
nate shelf, and the same beds that underlie the mentioned Mesozoic beds, cannot be
considered equal. Owing to these facts well founded by observations the idea on the
Sava nappe has been entirely rejected by us. The concept that the North Karavanke
overthrust could be connected with the overthrust of the Paleozoic beds in the Sou-
thern Karavanke, the so called Southkaravanke overthrust, moved from south north-
wards on the Košuta unit, is based on the idea byFrisch(1978) who believed that
after the collision of the Adriatic plate with the Eastern Alps the first was overthru-
sted on the second. This idea was resumed also by the authors of the geologic structu-
re of Austria (Oberhauser, 1980). It would be possible to discuss this subject ar-
gumentatively when investigations in the North Karavanke region and the Periadria-
tic tectonic zone will be acomplished. The obtained results are alreadly partly pu-
blished by P 1 a c e r (1996a), by J e 1 e n et al. (1997) and by F o d o r et al. (1998).
P r e m r u (1974, 1975, 1980, 1983a, 1983b) treated in his works, and especially in
the treatise on the structure of central Slovenia (1980), the most delicate part of the
territory east and west of the Ljubljana basin, as it is considered also in the present
paper. His kinematic starting point for the structure of the Sava folds is entirely dif-
ferent from ours, and it has been critically discussed in the treatise on the Sava folds
(Placer, 1998, this journal). Therefore its analysis will not be repeated here. The
major shortcoming of Premru's concept is the negation of hard facts of the structural
elements in their essential parts, to which attention was drawn already by K u š č e r
(1975). Therefore his overthrust interpretation must be rejected. It should be stressed,
however, that Premru was the first to study in detail on the basis of the data of the
Basic geologic map of Yugoslavia the contact between the Southern Alps and the Ex-
ternal Dinarides in the region of central Slovenia, that he in this region as the first
applied the structuro-facial analysis, and that he as the first draw attention to the
importance of transform faults in interpreting the genesis of paleosedimentation re-
gions in the Dinarides, and their place in the present structure. The transform faults
were not considered in the present paper, although they are, also in the light of our
Contribution to the macrotectonic subdivision_243
studies, an essential element for understanding the structure of the Alpine, Dinaric
and Pannonian regions.
Prispevek k makrotektonski rajonizaciji mejnega ozemlja
med Južnimi Alpami in Zunanjimi Dinaridi
Uvod
Formalno geotektonsko rajonizacijo ozemlja na stiku Vzhodnih Alp in Dinaridov
na Vzhodne Alpe, Južne Alpe, Zunanje in Notranje Dinaride, Jadransko ali Apulijsko
predgorje ter Panonski bazen (si. 1) so postopoma izoblikovale generacije geologov
vse od znamenite Kossmatove (1913) razprave o nagubanem zaledju Jadranske-
ga morja. Meja med Vzhodnimi in Južnimi Alpami ni sporna, ker poteka po Periadri-
atskem lineamentu in Ljutomerskem prelomu, ki verjetno predstavlja podaljšek Ba-
latonskega lineamenta. Oba termina označujeta isto disjunktivno enoto razmejeno z
Labotskim prelomom. Tudi Panonska udorina ne predstavlja nerešljivega problema,
čeprav ne moremo jasno določiti njenih meja. Iz zadrege si pomagamo z razprostra-
njenostjo njenih terciarnih sedimentov, zato govorimo o Panonskem bazenu. Resne
težave nastopijo pravzaprav šele pri razmejitvi Južnih Alp od Zunanjih in Notranjih
Dinaridov, ter pri ločevanju slednjih dveh enot. Predlog tektonske rajonizacije na si.
1 je narejen na podlagi podatkov Osnovne geološke karte Jugoslavije 1:100.000,
Buserjeve Geološke karte Slovenije 1:250.000 v tisku, Geološke karte Slovenije
1:500.000 (Buser & Draksler, 1993) in rezultatov novejših raziskav, kot je ra-
zvidno iz vsebine.
Metodologija predlagane tektonske rajonizacije temelji na krovni zgradbi Južnih
Alp in Zunanjih Dinaridov, na tektonskih elementih različnih hierarhičnih stopenj in
sedimentoloških kriterijih. Krovna zgradba Južnih Alp in Zunanjih Dinaridov je iz-
peljana iz ločilne ploskve (detachment) med kompetentnimi mezozojskimi pretežno
karbonatnimi kamninami in nekompetentnimi paleozojskimi klastiti, ki igrajo vlogo
mehke posteljice krovnih enot. Ločilna ploskev je bila ugotovljena v Posavskih gubah
in v Zgornjesavinjski dolini na območju Podolševe. Tektonski elementi prvega reda
so Periadriatski lineament, ki razmejuje Vzhodne Alpe od Dinaridov in preloma, ki
omejujeta enoto Tisa vzhodno od Zagreba od Dinaridov. Tektonski element drugega
reda je Južnoalpska narivna meja med Južnimi Alpami in Zunanjimi Dinaridi. Ta je
nastala znotraj prvotno enotnega sedimentacijskega prostora. Tretjega reda so Savski
in Idrijski prelom ter meje obsežnih krovnih enot znotraj Južnih Alp in Zunanjih Di-
naridov, medtem ko so prelomi dinarske smeri NW-SE in srednjemadžarske smeri
WSW-ENE ter Zunanjedinarska meja med Zunanjimi Dinaridi in Jadranskim ali
Apulijskim predgorjem četrtega reda. Meja med Zunanjimi in Notranjimi Dinaridi je
sedimentacijska, tako kot meja Panonskega bazena.
Meja med Južnimi Alpami in Zunanjimi Dinaridi
V tem prispevku bomo razpravljali predvsem o meji med Južnimi Alpami in Zuna-
njimi ter Notranjimi Dinaridi.
Šele s kartiranjem za Osnovno geološko karto Jugoslavije 1:100.000 se je izobliko-
244_Ladislav Placer
valo enotno mnenje, da spada Blegoš kot del Poljansko-Vrhniških nizov k Zunanjim
Dinaridom (Grad & Ferjančič, 1974, 1976; P r e m r u, 1980). To je bilo doka-
zano tudi s kinematsko analizo geneze blegoške strukture (Placer & Čar, 1997),
iz katere je razvidno, da so Blegoš izoblikovali najprej dinarsko usmerjeni narivi od
NE proti SW, nato pa obsežno narivanje Južnih Alp od severa proti jugu. Na območju
Blegoša je potemtakem mogoče povsem nedvoumno določiti strukturno mejo med
Zunanjimi Dinaridi in Južnimi Alpami, ki je narivna ploskev in poleg Periadriatske-
ga lineamenta najpomembnejša dislokacija obravnavanega prostora. Njen potek za-
hodno od Blegoša je sorazmerno jasen, saj se na severni strani nahajajo globljemor-
ske kamnine Slovenskega bazena, na južni strani pa karbonatne kamnine Trnovskega
pokrova. Litološka raznolikost obeh enot je na območju Blegoša in proti zahodu ja-
sno vidna do Tolmina, zahodno od tod pa je mejo mogoče slediti po strukturnih krite-
rijih, čeprav se tu stikajo podobne kamnine obeh imenovanih enot. To mejo je defini-
ral že K o s s m a t (1913) kot linijo Kobariški Stol - Cerkno, natančneje pa B u s e r
(1986, 1987) na listu Tolmin in Videm. Poseben pomen pri dokazovanju krovnega
značaja te meje imata Ponikvanska in Seniška tektonska krpa pri Tolminu. Nadaljnji
potek obravnavane narivne ploskve proti zahodu je povzet po S 1 e j k u et al. (1986),
ki jo vlečejo do recentnega tektonskega jarka po dolini Tilmenta med Guminom in
Mužacem ter naprej proti jugozahodu. Za opisano mejo predlagajo termin „Southal-
pine front", ki ga prevajamo kot Južnoalpska meja, oziroma meja Južnih Alp ali
Južnoalpska narivna meja. C a r u 11 i et al. (1990) pa so predlagali termin „Periadri-
atic overthrust" oziroma Periadriatski nariv. V tem prispevku smo uporabili starejšo
varianto, ker je bolj določna.
Proti vzhodu je Južnoalpsko mejo mogoče slediti do Kranja in nato ostro proti ju-
go-jugozahodu, vzhodno od Škofje Loke pa ponovno proti vzhodu do Medvod ob za-
hodnem robu Ljubljanske kotline, nakar se pričenjajo težave, ki zahtevajo obširnejšo
razlago. Da bi vprašanje pravilno razumeli, si najprej oglejmo Trnovski pokrov, ki je
del Zunanjih Dinaridov in njegov odnos do Južnih Alp in Posavskih gub. Le-te se po
novi definiciji (Placer, 1998, ta revija) razprostirajo le vzhodno od Ljubljanske ko-
tline, zahodno od tod pa v strukturnem smislu ne obstojajo. Trnovski pokrov obsega
Trnovski gozd z Banjšicami, Idrijsko-Žirovsko ozemlje in Škofjeloško-Polhograjsko
ozemlje. Narinjen je od NE proti SW na Hrušiški pokrov, nanj pa so od severa proti
jugu narinjene Južne Alpe ob pravkar omenjeni Južnoalpski meji. Iz notranje zgrad-
be Trnovskega pokrova sledi (Mlakar, 1969; Placer, 1973, 1981), da tvori njegova
narivna ploskev poševni rez tako, da so najmlajše kamnine v smeri narivanja razvite
v čelu pokrova nad Vipavsko dolino, kjer nastopajo kredne in paleocenske plasti, naj-
starejši karbonskopermski klastiti pa v korenu pokrova na Škofjeloško-Polhograj-
skem ozemlju. Tukaj so le-ti narinjeni na triasne kamnine Poljansko-Vrhniških nizov,
ki so v širšem smislu del mezozojskih kamnin južne Slovenije, v ožjem pa del
Hrušiškega pokrova. Nasprotno pa ležijo karbonskopermske kamnine Litijske anti-
klinale južno in vzhodno od Ljubljanske kotline dosledno pod mezozojskimi kamni-
nami južne Slovenije in ni nobenega posrednega ali neposrednega dokaza, da bi bilo
kako drugače. Anomalijo je opazil že K o s s m a t (1913) in jo rešil tako, da je nariv
Škofjeloško-Polhograjskega ozemlja, ki ga pa ni vzporejal z narivom Trnovskega
gozda, omejil na območje Poljansko-Vrhniških nizov, Ljubljanskega barja in Golovca
južno od Ljubljane. Enako sta za njim povzela Winkler (1923) in Rakovec
(1956). Novo rešitev je posredoval Mioč (1976, 1981) z idejo o Savskem pokrovu, ki
naj bi zajemal Idrijsko-Žirovsko in Škofjeloško-Polhograjsko ozemlje ter karbonsko-
permske in mezozojske plasti Posavskih gub in bil porinjen proti jugu na mezozojske
Contribution to the macrotectonic subdivision_245
plasti južne Slovenije. Da so karbonskopermske plasti Litijske antiklinale narinjene
proti jugu sta menila tudi P r e m r u (1980, 1983a, 1983b) in M 1 a k a r (1987) ter av-
torji Strukturnega modela Italije (B i g i et al., 1990). Nasprotno pa je B u s e r (1978,
1979) tako kot Kossmat, Winkler in Rakovec menil, da ležijo karbonskopermske pla-
sti Litijske antiklinale pod mezozojskimi skladi južne Slovenije. S pilotskimi razi-
skavami smo prišli do enakega sklepa kot Buser.
Iz lege karbonskopermskih skladov zahodno in vzhodno od Ljubljanske kotline to-
rej sledi, da ležijo te plasti v osrednji Sloveniji v dveh različnih tektonskih enotah.
Tiste na zahodu pripadajo Trnovskemu pokrovu, tiste na vzhodu pa ležijo pod mezo-
zojskimi skladi južne Slovenije oziroma pod Hrušiškim pokrovom in narivnimi eno-
tami vzhodno od le-tega. Da bi v smislu te ugotovitve razumeli problem zgradbe
osrednje Slovenije, si moramo pobliže ogledati krovno zgradbo jugozahodne Sloveni-
je (P 1 a c e r 1981, si. 7a), ki jo poenostavljeno podajamo v dveh profilih na si. 2 in na
si. 3.
Iz odnosa med Trnovskim in Hrušiškim pokrovom na si. 2a je razvidno, da karbon-
skopermske plasti Trnovskega pokrova v severovzhodnem delu profila prekrivajo
enake plasti Hrušiškega pokrova. Ker je profil narejen po faktografskih podatkih o
legi, notranji zgradbi, debelini in dolžini krovnih enot ter dolžini narivanja, za-
ključujemo tako kot v prejšnjem odstavku, da ležijo karbonskopermske plasti Škof je-
loško-Polhograjskega ozemlja hkrati na mezozojskih kamninah južne Slovenije in na
karbonskopermskih plasteh Litijske antiklinale vzhodno od Ljubljanske kotline. Te
pa ležijo dosledno pod karbonatnim sedimentnim pokrovom južne Slovenije. Glede
na to, da izvajamo krovno zgradbo Zunanjih Dinaridov iz enotne ločilne ploskve (de-
collement, detachment), je mogoče skleniti, da predstavlja meja med karbonskoper-
mskimi skladi Litijske antiklinale, ki ponekod vključujejo tudi grodenske plasti,
vzhodno od Kuma pa tudi werfenske in srednjetriasne plasti, nasproti mezozojskim
plastem komplicirano zgrajeno ločilno ploskev. Zaradi tega je povsem razumljivo, da
imamo v Posavskih gubah mlajše plasti narinjene na starejše, saj je za ločilno ploskev
značilen vzporedni ne pa poševni rez. Ta posebnost pogosto predstavlja osnovo za
ugovor proti ideji o krovni ali narivni zgradbi tega dela Slovenije. Ločilna ploskev
poteka tudi znotraj karbonskopermskih plasti, zato je njena lega na meji med paleol-
zojskimi in mezozojskimi plastmi v Posavskih gubah na si. 1 v pretežni meri formal-
na.
Jugovzhodna meja Trnovskega pokrova ima prečnodinarsko smer SW-NE. V raz-
pravi o zgradbi jugozahodne Slovenije (Placer, 1981) smo to utemeljevali z vpadom
osi velikih narivnih gub v čelu pokrova proti severozahodu. Vendar to dejstvo ni za-
dosten razlog za anomalno smer obravnavane meje, saj na območju Poljansko-Vr-
hniških nizov Trnovski pokrov ne visi več proti severozahodu, smer te meje pa se za-
radi tega ne spremeni. Bolj verjetno je, da predstavlja jugovzhodna meja Trnovskega
pokrova bočno mejo te obsežne krovne enote, katere pretežni del je prekrit z Južnimi
Alpami. Stanje je shematsko prikazano na si. 3, na kateri so zaradi lažje orientacije
narisani tudi Poljansko-Vrhniški nizi in Blegoš. Obseg Trnovskega pokrova in izje-
mna struktura Blegoša kažeta na velik pomen Južnoalpske meje. Ob njej domnevamo
velik premik, ki bi ga lahko razložili z obsežno rotacijo Zunanjih Dinaridov nasproti
Južnim Alpam ali pa s prekrilnim narivanjem brez rotacije kot menijo npr. P r e m r u
(1980), Doglioni & Siorpaes (1990) terPolinski & Eisbacher (1992).
Ker ima Trnovski pokrov omejen obseg, velja model na si. 2a in njegova kinemat-
sko-dinamska izpeljava z eksponencialnim narivnim nizom (si. 4a) le za profil, ki po-
teka preko Trnovskega pokrova (profil 1-1 na si. 3), medtem ko so razmere v profilu
246_        Ladislav Placer
2-2 (si. 3) izven Trnovskega pokrova na slikah 2b in 3 nekoliko drugačne. Čeprav je
Trnovski pokrov prvotno segal verjetno nekoliko dlje proti jugovzhodu in bil pozneje
erodiran, menimo, da njegov obseg v tej smeri ni mogel biti bistveno večji od da-
našnjega, saj nikjer v južni Sloveniji ne najdemo tektonskih krp, ki bi dokazovale
nasprotno. Zato je treba zgradbo Zunanjih Dinaridov jugovzhodno od Trnovskega
pokrova izvajati iz profila na si. 2b, in sicer kot kopičenje krovnih enot na jugozaho-
du katerih najvišji člen je Hrušiški pokrov, na severovzhodu pa kot ločilno narivno
luskasto strukturo, ki je bila ugotovljena npr. z vrtino v Dolenjskih Toplicah
(P r e m r u et al., 1977), kjer so jurske plasti narinjene na kredne. Lahko bi torej hi-
potetično govorili o krovni zgradbi izhajajoči iz ločilne ploskve z domnevnim kombi-
niranim narivnim nizom (P 1 a c e r, 1982), kot je prikazan na si. 4b.
Iz profila 1-1 na si. 2 in 3 je mogoče tudi sklepati, da je negativna anomalija Moho-
rovičičeve diskontinuitete 45 km na si. 5 (povzeto poCarulliju et al., 1990, si. 3)
na razmeroma ozkem prostoru med Tržaškim zalivom in Ljubljansko kotlino, nastala
zaradi izostatičnega ugrezanja območja, kjer so krovne enote nakopičene ena vrh
druge. Obseg anomalije v smeri NW-SE pa ustreza legi in razprostranjenosti Trnov-
skega pokrova. Karto, ki jo podajajo Carulli et al. smo uporabili zato, ker je bolj gra-
duirana od Strukturne karte Mohorovičičeve diskontinuitete (D r a g a š e v i č et al.,
1989) za območje Jugoslavije. V korenu krovnih enot pa nasprotno opažamo izosta-
tični dvig mehke posteljice iz nekompetentnih karbonskopermskih plasti pod mezo-
zojskimi skladi. Opisani odnos med krovno zgradbo in Mohorovičičevo diskontinui-
teto je ponazorjen na profilu na si. 6, ki je istoveten s profilom 1-1, le da smo pri nje-
govi konstrukciji uporabili realno stanje s si. 1, vendar brez Idrijskega preloma, saj
obravnavamo le krovno zgradbo. Anomalija jugovzhodno od Trnovskega pokrova je
sicer nekoliko blažja (40 km), vendar še vedno poudarjeno izraža izostatični ugrezek
narinjenih enot in dvig na območju Posavskih gub. Izdanjanje karbonskopermskih
plasti v Polhograjsko-Škofjeloškem hribovju in na območju Posavskih gub ima torej
logično razlago. Dopolnimo jo lahko tudi z dvigom Posavskih gub znotraj Savskega
kompresijskega klina (P 1 a c e r, 1998, ta revija).
Iz navedenega moremo sklepati, da pripadajo karbonskopermske plasti osrednje
Slovenije v celoti Zunanjim Dinaridom. Tako je menil že B u s e r (1979).
Pri iskanju pravega odgovora na vprašanje o poteku Južnoalpske meje vzhodno od
Medvod, stojimo kljub razrešitvi vprašanja o pripadnosti karbonskopermskih plasti
dvema strukturnima enotama pred dilemo, ki je na podlagi danes znanih podatkov še
ne moremo zadovoljivo rešiti. Pojavlja se več vprašanj, prvo se dotika starosti krov-
nega narivanja, drugo pa notranje zgradbe krovnih enot. Dinarski pokrovi so poveza-
ni z genezo eocenskih flišnih plasti, torej se je ciklus tega narivanja verjetno zaključil
konec eocenske dobe. Južnoalpski pokrovi prekrivajo dinarske in so po normalni lo-
giki lahko le mlajši. V Posavskih gubah tvorijo mezozojske kamnine eno ali več ob-
sežnih krovnih enot, ki so bile narinjene pred odložitvijo trboveljskih plasti (Plac-
e r, 1998, ta revija; prvotno soteske plasti, nato psevdosoteške plasti -Jelen et al.,
1992) v srednjem ali zgornjem oligocenu. Logično bi torej bilo, da bi eno ali več krov-
nih enot, ki obsegajo celotne Posavske gube vzporejali z dinarskimi pokrovi, vendar
jih v facialnem smislu lahko primerjamo le s kamninami Slovenskega bazena in nje-
govega obrobja zahodno od Škofje Loke in Kranja.
Nadalje obstaja vprašanje starosti Julijskega pokrova kot smo poimenovali pokrov
Julijskih in Kamniško-Savinjskih Alp. Le-tega sta Grad & Ferjančič(1976)
imenovala Jelovški pokrov, M i o č (1981) Julijsko-Savinjski pokrov, M i o č (1983) in
P r e m r u (1983b) Savinjski nariv, Jurkovšek (1987b) pokrov Julijskih Alp,
Contribution to the macrotectonic subdivision_247
B u s e r (1986) Krnski pokrov, K r y s t y n et al. (1994) v nekoliko modificirani obli-
ki pa Krnski oziroma Pokljuški pokrov. V tem prispevku smo kljub pravici prvega
prevzeli Miočev predlog in ga modificirali v Julijski pokrov, ki obsega Julijske in Ka-
mniško-Savinjske Alpe. Na starost Julijskega pokrova lahko le posredno sklepamo
po odnosu krovnega nariva v Julijskih Alpah do oligocenskih plasti Ljubljanske ko-
tline, ki izdanjajo na njenem celotnem območju in jo po podatkih Osnovne geološke
karte, listov Celovec (Buser & Cajhen, 1978) in Kranj (Grad &
F e r j a n č i č , 1974) pod kvartarnimi naplavinami prekrivajo skoraj v celoti. Zato
bi lahko sklepali, da je z oligocenskimi plastmi prekrita tudi narivna ploskev Julij-
skega pokrova, če se spusti pod oligocenske plasti Ljubljanske kotline. Razmere v
Kamniško-Savinjskih Alpah so na prvi pogled drugačne, vendar interpretacija s
krovnimi narivi na oligocenske plasti na listu Celovec (Buser & Cajhen, 1978,
profil C-D) ali na listu Ljubljana (P r e m r u 1983a, profil A-B) ni dokazana. Doka-
zljivi so le manjši narivi postsarmatske, po vsej verjetnosti postsrednjepliocenske sta-
rosti, ki so posledica kompresije znotraj Savskega kompresijskega klina in krčenja
prostora. Na podlagi teh ugotovitev menimo, da bi se Kamniško-Savinjske in Julijske
Alpe lahko narinile na pelagične sedimente Slovenskega bazena že pred srednjim,
oziroma zgornjim oligocenom tako kot ena ali več krovnih enot v Posavskih gubah in
kot velja tudi za osrednji del Južnih Alp (Doglioni & Bosellini, 1987). Med
koncem eocena in srednjim do zgornjim oligocenom bi bilo lahko dovolj časa za for-
miranje Južnoalpske krovne zgradbe. Po drugi strani pa B u s e r (1980), P r e m r u
(1980) terPolinski & Eisbacher (1992) uvrščajo pokrove Julijskih in Ka-
mniško-Savinjskih Alp v neogen. Vprašanje ni preprosto. Rešiti ga bo mogoče le z ob-
sežnimi raziskavami. Vsekakor imajo oligocenske plasti pri Bohinju, na Veliki Plani-
ni in na Kopišču ob Kamniški Bistrici za ugotavljanje starosti Julijskega pokrova ve-
lik pomen. Pripomniti pa velja, da je ločevanje nastanka Julijskega pokrova od
Južnoalpske meje nelogično in izvira iz pomanjkljive strukturne faktografije
območja Julijskih in Kamniško-Savinjskih Alp.
Glede notranje zgradbe krovnih enot in smeri narivanja smo že dejali, da je zaho-
dno od Ljubljanske kotline mogoče na podlagi južnoalpskih (W-E) in dinarskih (NW-
SE) elementov strukture ločiti dinarsko od južnoalpske krovne zgradbe. Zato bi
pričakovali, da so na sorazmerno kratki razdalji vzhodno od Ljubljanske kotline ra-
zmere enake ali vsaj podobne. Vendar je struktura drugačna. Njena drugačnost je po-
vezana z genezo Posavskih gub znotraj Savskega kompresijskega klina (P 1 a c e r,
1998, ta revija), zaradi česar so se le-te močno nagubale v smeri W-E, pri čemer so se
dinarske krovne strukture navzven močno zabrisale. Da bi lahko ugotovili potek
Južnoalpske meje, bi morali analizirati notranjo strukturo mezozojskih kamnin na
območju Posavskih gub. Ker smo na novo skartirali le širše območje Laške sinklinale,
smo opravili le analizo vpadov debeloplastnatega srednjetriasnega in glavnega dolo-
mita ter dachsteinskega apnenca na tem območju, saj se v debeloplastnatih kamni-
nah odražajo regionalni vidiki deformiranja razmeroma neodvisno od krajevnih vpli-
vov. Te kamnine nastopajo zahodno od Kuma. V severnem krilu Laške sinklinale jih
najdemo na Rebri nad Kolovratom severozahodno od Izlak, v južnem krilu pa med
Kumom in Slemškom nad Vačami. V južnem krilu sinklinale vpadajo plasti generalno
proti zahodu do zahodu-severozahodu, v severnem krilu pa proti jugozahodu do ju-
go-jugozahodu. S preprosto rotacijo okoli osi W-E, ki je vzporedna osi gubanja, je
mogoče ugotoviti, da ležijo poli plasti enega in drugega krila sinklinale v isti ravnini
(si. 7), smer plasti v temenu sinklinale, ki je konstruirana pa je dinarska (NW-SE).
Poleg strukturnega obstoja tudi facialni vidik. Značilni kondenzirani profil groden-
248_Ladislav Placer
skih in belerofonskih plasti v useku avtoceste pri Višnji Gori (Skaberne, ustna izjava)
smo odkrili tudi v Borovniškem peskokopu v Kisovcu v Laški sinklinali, kar bi kaza-
lo na isti sedimentacijski prostor. Lega zgornjetriasnih plasti in razvoj permskih pla-
sti bi lahko služila za dokaz, da pripadajo mezozojske kamnine v Posavskih gubah,
ali vsaj del južno od Trojanske antiklinale, Zunanjim Dinaridom. Za potrditev takega
sklepa pa bi morali analizirati celotne Posavske gube. Zato temu podatku ne moremo
pripisovati odločilnega pomena.
Z upoštevanjem elementov starosti krovnega narivanja in notranje zgradbe krov-
nih enot, se še nismo približali jasnemu odgovoru o poteku meje Južnih Alp vzhodno
od Ljubljanske kotline. Ugotovili pa smo, da je krovna zgradba v Posavskih gubah
predsrednje do predzgornjeoligocenske starosti, da je Julijski pokrov enake ali pa
postsarmatijske starosti in da je Južnoalpska narivna meja ob kateri so se kamnine
Slovenskega bazena narinile proti jugu zahodno od Ljubljanske kotline časovni ekvi-
valent krovne zgradbe Posavskih gub, saj oligocenski sedimenti v okolici Medvod
prekrivajo Južnoalpsko mejo. Glede na povedano obstojata o poteku Južnoalpske
meje vzhodno od Ljubljanske kotline dve varianti, od katerih ima vsaka nekaj pre-
dnosti in nekaj slabosti. Obe sta prikazani na si. 8.
Po varianti 8a poteka meja Južnih Alp po severnem robu karbonskopermskega je-
dra Trojanske antiklinale, po varianti na si. 8b pa po severnem robu karbonskoper-
mskega jedra Litijske antiklinale, pri čemer je v Južne Alpe vključena tudi Preveška
tektonska krpa (po Preveškem hribu nad Polšnikom, 873 m). Po prvi varianti bi k
Južnim Alpam spadali zgornjetriasni, jurski in kredni pelagični sedimenti Slovenske-
ga bazena, medtem ko naj bi triasne kamnine v podlagi in krilih Laške sinklinale pri-
padale najvišjemu pokrovu dinarske provenience. Na to bi kazala lega plasti zahodno
od Kuma. Ta varianta sicer upošteva strukturni vidik lege plasti in podoben razvoj
kondenziranih grodenskih in belerofonskih plasti v Kisovcu in pri Višnji Gori, pa tu-
di diskordantno lego krednih globljemorskih plasti na triasnih platformnih karbona-
tih, kar je značilno za notranji pas Zunanjih Dinaridov. Vendar ne smemo zanemariti
pomanjkljivosti, da smo analizirali lego plasti na majhnem delu Posavskih gub, in da
kaže razvoj mezozojskih plasti na tem območju bolj na postopen prehod od pretežno
karbonatnega faciesa srednje in zgornjetriasnih plasti na jugu do klastičnega in pela-
gičnega razvoja na severu kot pa na obsežno tektonsko prekinitev, če bi Južnoalpska
meja potekala po severnem robu Trojanske antiklinale. Zato smo se pri tem stanju
raziskanosti odločili za varianto 8b kot delovno hipotezo, ki je sicer skladna s
Kossmatovim (1913) inWinklerjevim (1923) razumevanjem povezave
obravnavane narivne ploskve med zahodnim in vzhodnim obrobjem Ljubljanske ko-
tline, vendar iz različnih teoretskih izhodišč.
Dileme v zvezi z obravnavanim vprašanjem so širše. Tičejo se formacijskih in
strukturnih vprašanj (geometrijskih in kinematskih), paleomagnetizma, palinspasti-
ke, paleogeografije in globalne tektonike. Zato je potreba po kompleksnem pristopu
k reševanju te problematike na Slovenskem morda najbolj akutna in bi morala biti
neposredno povezana z vsestransko obdelavo v okviru geološke karte 1:50.000. Neja-
snost ni povezana samo s potekom Južnoalpske meje vzhodno od Ljubljanske kotline,
temveč tudi z vprašanjem njenega globalnega pomena. Danes zaradi nezadostne razi-
skanosti ne moremo ugotoviti ali se nadaljuje v Srednjetransdanubijsko cono ali pa
zavije proti jugovzhodu. Na podlagi prevladujočih globalnih pogledov na genezo Pa-
nonske udorine (npr. Csontos et al., 1992; H o r v a t h & Tari, 1998), smo v tej
razpravi uporabili prvo varianto, ki pa je zgolj hipotetična. Orientirali smo se po me-
zozojskem ofiolitnem melanžu Kalnika in Medvednice, ki ju sicer ne moremo nepo-
Contribution to the macrotectonic subdivision_249
sredno povezovati z globljemorskimi kamninami Posavskega in Krškega hribovja ter
Gorjancev, menimo pa, da pripadajo v širšem smislu Notranjim Dinaridom.
Ob tej priliki bi opozorili na mnenje P r e m r u j a (1980), Doglionija &
Siorpaesa (1990) terPolinskega & Eisbacherja (1992) o genezi zami-
ka med Južnimi Alpami in Zunanjimi Dinaridi iz česar izhaja, da v Južnih Alpah lah-
ko pričakujemo relikte dinarsko usmerjenih elementov strukture. Zaradi tega je izbi-
ra variante 8b v tem trenutku primernejša.
Omeniti pa velja še domnevo S 1 e j k a et al. (1986) in C a r u 11 i j a et al. (1990),
da je Južnoalpska meja zahodno od Idrijskega preloma še aktivna. Misel je povezana
z nasledstvenimi učinki in kaže na kompleksnost ugotavljanja starosti disjunktivnih
struktur na prostoru, ki je prestal več tektonskih faz.
Diskusija
Geotektonska rajonizacija slovenskega ozemlja temelji na dveh megadisjunktivnih
strukturah, Periadriatskem lineamentu in Južnoalpski meji ter na notranje heteroge-
ni in ne povsem jasno zamejeni Panonski udorini. Zaradi tega je enostavneje govoriti
o Panonskem bazenu, čeprav se na žalost v njem ne odraža le geometrija Panonske
udorine, temveč tudi mejnih ozemelj z elementi nasledstvenih deformacij, ki z udori-
no niso genetsko povezane.
Cilj pričujoče razprave ni podrobna genetska, temveč generalna formalna tekton-
ska rajonizacija Slovenije in določitev najpomembnejših tektonskih enot regionalne-
ga pomena, ki temeljijo na globalnih principih in na krovni zgradbi izhajajoči iz geo-
metrije ločilne (detachment) tektonike.
1. Vzhodne Alpe obsegajo območje metamorfnih kamnin in območja mezozojskih
karbonatnih kamnin (Dravski niz in ostalo). Dravski niz sega na naše ozemlje kot Se-
verne Karavanke in njihovi vzhodni relikti pri Mislinji in Zrečah.
2. Dinaridi so od Vzhodnih Alp razmejeni s Periadriatskim lineamentom. Delimo
jih na Južne Alpe ter Zunanje in Notranje Dinaride.
2a. Južne Alpe ležijo med Periadriatskim lineamentom in Južnoalpsko mejo. Nji-
hova pomembna strukturna enota je Periadriatska tektonska cona (Jelen et al.,
1997; P 1 a c e r, 1998, ta revija) med Periadriatskim lineamentom in Savskim prelo-
mom. V tem članku se ne ukvarjamo poglobljeno z vprašanjem krovne zgradbe
Južnih Alp, podajamo pa nekaj splošnih izhodišč, ki bi jim morali v bodoče posvetiti
vso pozornost. Kljub premiku ob Savskem prelomu najsi je 25, 40 ali 65-70 km
(Placer, 1996b), moramo Julijske in Kamniško-Savinjske Alpe obravnavati kot
enoten tektonski objekt v katerem zavzemajo osrednje mesto kamnine Slovenskega
bazena. Te po K r y s t y n u et al. (1994) nastopajo v Tolminskem pokrovu, ki leži
pod Julijskim pokrovom. Glede na razprostranjenost slednjega ugotavljamo, da je ta
na jugu narinjen na kamnine Slovenskega bazena (Tolminsko, Baška grapa, Selška
dolina, Županje Njive pri Kamniku, dolina Črne pri Kamniku), na severu na območju
lista Ravne pa leži na kamninah spodnje do srednjetriasne starosti, morda tudi zgor-
njetriasne (Mioč, 1983; Mioč & Žnidarčič, 1983). To navaja na misel, da tvo-
rijo kamnine s severnega obrobja Julijskega pokrova podlago, ponekod pa tudi bočni
ekvivalent sedimentov Slovenskega bazena in pripadajo verjetno Tolminskemu po-
krovu tako kot kamnine Slovenskega bazena. Zaradi hipotetičnosti te domneve nava-
jamo „Tolminski pokrov" v takem obsegu v narekovajih. Na listu Ravne ležijo na
območju Podolševe spodnjetriasne kamnine „Tolminskega pokrova" tektonsko na
250_Ladislav Placer
karbonskih klastitih, ki predstavljajo mehko posteljico Južnih Alp. Ta enota poleg
paleozojskih zajema na listih Celovec ter Beljak in Ponteba tudi spodnje in srednje-
triasne plasti, sama narivna ploskev nasproti „Tolminskemu pokrovu" pa je verjetno
skrita znotraj iste formacije. Kamnine, ki bi jih lahko prištevali k paleozojski podlagi
„Tolminskega pokrova", se nahajajo tudi južno od Savskega preloma nad Kranjsko
goro in Ratečami (Jurkovšek, 1987a) nad njimi pa nastopajo spodnje in srednje-
triasne plasti „Tolminskega pokrova", ki se po geološki karti s Strukturnega modela
Italije (B i g i et al., 1990) vlečejo v ozkem pasu ob južni strani Belškega preloma da-
leč proti zahodu. Na Strukturnem modelu je meja teh plasti nasproti zgornjetriasnim
normalna, vendar domnevamo, da obstojajo tu enake razmere kot na listu Beljak in
Ponteba (Jurkovšek, 1987a, profil A-B), zato tudi tu predvidevamo obstoj „Tol-
minskega pokrova", medtem ko se paleozojske plasti pojavljajo le na območju Kran-
jske gore in Rateč. K „Tolminskemu pokrovu" spadajo tudi mezozojske kamnine Po-
savskih gub, ki smo jih z določitvijo poteka Južnoalpske meje po severnem robu Li-
tijske antiklinale reducirali na eno krovno enoto. Vendar moramo tako rešitev obrav-
navati hipotetično.
Paleozojske kamnine mehke posteljice južnih Karavank in triasne kamnine kara-
vanškega pasu „Tolminskega pokrova" med Savskim prelomom in Periadriatskim li-
neamentom so B u s e r (1980), M i o č (1983) in Jurkovšek (1987a) uvrstili v
Južnokaravanško enoto, ki naj bi zajemala tudi spodnje in srednjetriasne plasti. Gle-
de na pomen paleozojske podlage predlagamo zanjo termin Javorniška enota po Ja-
vorniškem Rovtu nad Jesenicami.
Glede na predstavljena izhodišča nastopajo v Južnih Alpah Javorniška in Košuti-
na enota ter „Tolminski" in Julijski pokrov. Javorniška enota je mehka posteljica
Južnih Alp. Košutina enota je tektonska leča iz mezozojskih kamnin med Periadriat-
skim lineamentom in več prelomi znotraj Periadriatske tektonske cone (B r e n č i č
et al., 1995), ki so imeli tekom razvoja slednje različno dinamsko vlogo. „Tolminski"
in Julijski pokrov sta krovni enoti narinjeni generalno od severa proti jugu na Zuna-
nje Dinaride. Boskovec, Paški Kozjak, Konjiška gora, Boč in Ravna gora so struktur-
no del Južnih Alp, po kamninski sestavi smo jih hipotetično uvrstili v „Tolminski po-
krov". Po kamninski sestavi bi bila Košutina enota v Karavankah lahko del Julijske-
ga pokrova, ki je znotraj Periadriatske tektonske cone močno tektonsko preoblikova-
na. Vendar tega v shemi rajonizacije zaradi hipotetičnosti nismo upoštevali.
Julijski in „Tolminski" pokrov sta v smeri W-E skledasto usločena, kar je mogoče
povezati z regionalno komprimacijo. Meja med Javorniško enoto in „Tolminskim po-
krovom" bi lahko bila istovetna z narivno ploskvijo Južnoalpske meje. Južnoalpska
narivna meja je hkrati tudi južna meja „Tolminskega pokrova".
2b. Zunanji Dinaridi so nasproti južnim Alpam zamaknjeni za 30° do 45° in pod
slednje podrinjeni. Sestavljeni so iz treh pasov: a - iz zunanjega paravtohtonega z
ohranjenimi terciarnimi sedimenti v jedrih sinformnih struktur (Kraški naluskani
prag, Komenska narivna gruda), b - iz osrednjega alohtonega dela, kjer so terciarni
sedimenti le izjemoma ohranjeni (Snežniški, Hrušiški, Trnovski pokrov ter nerazčle-
njena narivna zgradba severovzhodno od Hrušiškega pokrova), in c - iz notranjega
alohtonega pasu, ki predstavlja prehodno območje med Zunanjimi in Notranjimi Di-
naridi oziroma t.i. pregibno zono (Pleničar & Premru, 1975), ki jo nekateri
avtorji uvrščajo v Notranje Dinaride. Zanjo je značilna migracija pelagiala skozi
zgornji trias, juro in kredo. Posebno lego v Zunanjih Dinaridih ima Trnovski pokrov,
ki je le skrajni jugovzhodni vidni del večjega pokrova, podrinjenega pod Južne Alpe.
Izjemna je njegova lega in zgradba, saj se na njegovem severozahodnem robu prične
Contribution to the macrotectonic subdivision_251
degradacija dinarske karbonatne platforme že v zgornji kredi. Ker se degradacija po-
javlja najprej v Trnovskem pokrovu sodimo, da je ta podatek eden pomembnejših za
študij palinspastike Dinaridov. Na si. 1 so poleg Trnovskega pokrova izrisane tudi
narivne meje Hrušiškega pokrova, Snežniške in Komenske narivne grude ter Kraške-
ga naluskanega praga, kot smo ustrezneje preimenovali Čičarijsko naluskano zgrad-
bo (P 1 a c e r, 1981). Slednja ima vlogo narivnega čela Zunanjih Dinaridov. Meje na-
rivnih enot severovzhodnega dela Zunanjih Dinaridov niso izrisane, ker njihov potek
še ni analitično proučen.
Karbonskopermske plasti v Posavskih gubah so del Zunanjih Dinaridov.
2c. Prehodno območje med Zunanjimi in Notranjimi Dinaridi. Na območju Slove-
nije v megatektonskem smislu ni Notranjih Dinaridov. Obstaja le prehodno območje
med Zunanjimi in Notranjimi Dinridi, kjer so jurski in kredni pelagični sedimenti
odloženi diskordantno na triasnih in starejših kamninah Zunanjih Dinaridov ali pa
zgornjetriasni šelf polagoma prehaja v pelagial (Ogorelec & Doze t, 1997), za-
radi česar nekateri prehodno območje uvrščajo v Notranje Dinaride. Na območju Po-
savskih gub je prehodno območje med Notranjimi in Zunanjimi Dinaridi podrinjeno
pod podobne kamnine Slovenskega bazena oziroma Južnih Alp. Odprto ostaja
vprašanje pripadnosti podlage globokomorskih sedimentov Medvednice in Kalnika,
saj po vsej verjetnosti pripada posebni strukturni enoti znotraj Srednjemadžarske
tektonske cone, zato ju v tektonskem smislu nismo uvrstili. Podobne težave povzroča
južno pobočje Ivančice, če je hipotetična Južnoalpska meja na tem mestu postavljena
pravilno.
Južnoalpska narivna meja loči podobne ali enake kamnine Trnovskega pokrova in
prehodnega območja med Notranjimi in Zunanjimi Dinaridi od Slovenskega bazena.
V času nastajanja so bile te kamnine bolj ali manj daleč narazen. Razdaljo med pale-
ogeografskimi enotami v času sedimentacije bo mogoče oceniti po palinspastični re-
konstrukciji tektogeneze Dinaridov, po detajlni kinematski in dinamski analizi me-
gastrukturnih enot in po detajlni analizi faciesov.
3. Jadransko ali Apulijsko predgorje je avtohton dinarske narivne in krovne
zgradbe. Skupaj z Zunanjimi Dinaridi je podrejeno pod Južne Alpe.
4. Panonski bazen je heterogena tektonska enota. Njegovo podlago sestavljajo
vzhodni oziroma vzhodno-severovzhodni podaljški vzhodnoalpskih in dinarskih geo-
tektonskih enot, ki so pogreznjene pod terciarne sedimente Paratetide. Po H a a s u
et al. (1995) sestavljajo te enote obsežne srednjealpske terrane, sestavljene pretežno iz
kontinentalne skorje; Vzhodnoalpskega iz metamorfnih kamnin, Transdanubijskega
iz kamnin Dravskega niza oziroma Severnih Karavank, Srednjetransdanubijskega iz
kamnin Južnih Alp in Tisinega iz kamnin z evropskimi favnističnimi elementi. Iz in-
terpretacije Transdanubijskega in Srednjetransdanubijskega terrana sledi, da tvori
mejo med njima Balatonski lineament, ki je podaljšek Periadriatskega lineamenta
vzhodno od Labotskega preloma. Na ozemlju Slovenije je Balatonski lineament
označen kot Ljutomerski prelom. Mejo med Transdanubijskim in Vzhodnoalpskim
terranom tvori Rabski prelom (Haas et al., 1995; H o r v a t h & Tari, 1998), ki
naj bi bil tudi izvorna struktura Severnokaravanškega nariva. Na karti na si. 1 Rab-
ski prelom ni narisan, ker njegov potek na obravnavanem ozemlju na Osnovni geo-
loški karti (listi Goričko in Leibnitz, Maribor, Čakovec in Rogatec) ni določen.
Zgradba Periadriatske tektonske cone se odraža v različnem razvoju terciarnih
plasti severno in južno od te cone in znotraj nje (Jelen et al., 1992, 1997). Ta razno-
likost je odsev njene tektogeneze, ki so jo natančneje obdelali F o d o r et al. (1998).
252_Ladislav Placer
Sklep
Predlagana shema makrotektonske rajonizacije je delovna in je predstavljena kot
osnova za razpravo o tektonski zgradbi Slovenije. V njej smo skušali podati tiste ele-
mente globalne in krovne tektonike ozemlja na stičišču treh megastruktur, ki predla-
gano shemo osvetljujejo. Od teh so najpomembnejši:
1. Paleozojske plasti nastopajo v strukturno najbolj dvignjenih delih, za kar poda-
jamo kinematsko in dinamsko razlago: a - v izostatsko močno dvignjenem korenu Tr-
novskega pokrova, b - v močno stisnjeni in iztisnjeni Periadriatski tektonski coni in c
- v izostatsko dvignjenih Posavskih gubah, ki so bile poleg tega, tako kot Periadriat-
ska tektonska cona, v okviru Savskega kompresijskega klina dvignjene nad okolne
strukture.
2. Značilno zgradbo Zunanjih Dinaridov in razprostranjenost Trnovskega pokrova
potrjuje negativna anomalija Mohorovičičeve diskontinuitete na koti 45 km.
3. Pomen Južnoalpske meje je v celoti razviden šele tedaj, ko jo obravnavamo v
širšem cirkumadriatskem prostoru. Na stiku med Južnimi Alpami in Zunanjimi Di-
naridi jo je mogoče oceniti po legi Trnovskega pokrova in nenavadni dvojni narivni
strukturi Blegoša.
4. Težave pri določitvi poteka Južnoalpske meje vzhodno od Ljubljanske kotline so
povezane z deformacijami znotraj Savskega kompresijskega klina in strukturno po-
manjkljivo geološko osnovo v merilu 1:100.000.
Vprašanja, ki so ostala odprta so pomembna za palinspastično rekonstrukcijo ge-
neze Dinaridov in Panonskega bazena. Tako je npr. 1. vprašanje poteka Južnoalpske
meje vzhodno od Ljubljanske kotline, saj za palinspastiko tega prostora ni vseeno ali
zavija le-ta ob severnem robu Litijske antiklinale proti vzhodu-severovzhodu ali pro-
ti jugovzhodu. Od tega je odvisna končna izbira variante 8a ali 8b (si. 8) ali pa katere
druge. 2. Vprašanje poteka te meje je pomembno tudi za razlago vloge psevdoziljskih
plasti na območju Blegoša v Poljansko-Vrhniških nizih in v severnem krilu Laške
sinklinale v Posavskih gubah, kar je ena od zagonetk mejnega ozemlja med Južnimi
Alpami in Zunanjimi Dinaridi.
Nazadnje nam ostane še primerjava z nekaterimi interpretacijami zgradbe Sloven-
skega ozemlja, ki so nastale na podlagi kartiranja za Osnovno geološko karto. Misli-
mo predvsem na Miočevo idejo o Savskem pokrovu in zgradbi prehodnega ozemlja
med Vzhodnimi in Južnimi Alpami ter na Premrujevo interpretacijo osrednje Slove-
nije, čeprav smo o tem že razpravljali (P 1 a c e r, 1998, ta revija). Ker je v tem pris-
pevku predstavljena rajonizacija delovna, se ne bomo spuščali v detajlno analizo ra-
zlik. Omejili se bomo le na izhodišča posameznih hipotez, ki so bistveno različna, kot
se razlikujejo tudi interpretacije. Mioč v svojih delih uvaja dve novosti, Savski po-
krov (M i o č, 1976, 1981) in idejo o enoviti narivni zgradbi Južnih in Severnih Kara-
vank (Mioč, 1986, 1997). O Savskem pokrovu smo že dejali, da naj bi zajemal paleo-
zojske in mezozojske plasti Posavskih gub ter Škofjeloško-Polhograjskega in Žirov-
skega ozemlja. Porinjen naj bi bil proti jugu na karbonatni šelf Zunanjih Dinaridov.
Zapisali smo tudi, da ne moremo enačiti karbonskopermskih skladov Škofjeloško-
Polhograjskega ozemlja, ki ležijo na, in enakih skladov v Posavskih gubah pod mezo-
zojskimi plastmi južne Slovenije, oziroma takoimenovanim karbonatnim šelfom. Po-
leg tega paleozojske plasti pri Ortneku ne predstavljajo tektonskih krp, temveč ero-
zijska okna pod mezozojskimi plastmi. Zaradi teh dejstev, ki imajo faktografsko težo,
idejo o Savskem pokrovu v celoti zavračamo. Zamisel, da je Severnokaravanški nariv
povezan z narivom paleozojskih plasti v Južnih Karavankah, takoimenovanim
Contribution to the macrotectonic subdivision_253
Južnokaravanškim narivom, porinjenim od juga proti severu na Košutino enoto sloni
na ideji F r i s c h a (1978), ki je menil, da se je po koliziji Jadranske plošče z Vzho-
dnimi Alpami prva na slednje narinila. To idejo so povzeli tudi pisci geološke zgradbe
Avstrije (Oberhauser, 1980). O tej ideji bo moboče argumentirano razpravljati,
ko bodo končane sedanje raziskave Severnih Karavank in Periadriatske tektonske
cone, katerih delne rezultate so objavili P 1 a c e r (1996a), Jelen et al. (1997) in F o
dor etal. (1998).
P r e m r u (1974, 1975, 1980, 1983a, 1983b) je v svojih delih, posebej pa v razpravi
o zgradbi osrednje Slovenije (1980), obdelal najbolj občutljivi del v tem prispevku
obravnavanega ozemlja zahodno in vzhodno od Ljubljanske kotline. Njegovo kine-
matsko izhodišče o zgradbi Posavskih gub je povsem drugačno od našega in smo ga
kritično že obdelali v razpravi o Posavskih gubah (P 1 a c e r, 1998, ta revija), zaradi
česar analize tukaj ne bomo ponavljali. Glavna pomanjkljivost njegove ideje je, da v
bistvenih delih zanika faktografijo elementov strukture, na kar je K u š č e r (1975) že
opozoril. Zaradi tega moramo njegovo narivno interpretacijo zavrniti. Poudariti pa je
treba, da je na podlagi podatkov Osnovne geološke karte Jugoslavije prvi podrobneje
obdelal stik med Južnimi Alpami in Zunanjimi Dinaridi na območju osrednje Slove-
nije, da je v tem prostoru prvi uporabil strukturno-facialno analizo in da je prvi opo-
zoril na pomen transformnih prelomov pri interpretaciji geneze paleosedimentacij-
skih prostorov v Dinaridih in njihovega mesta v sedanji zgradbi. Transformnih prelo-
mov v tem prispevku nismo obravnavali, pomenijo pa tudi po naših raziskavah enega
bistvenih elementov razumevanja zgradbe alpsko-dinarsko-panonskega prostora.
Zahvala
Za skrben pregled članka in izredno koristne pripombe se zahvaljujem dr. Špeli
Goričan in dr. Katici Drobne. Za korekten prevod v angleščino se zahvaljujem prof.
dr. Simonu Pircu.
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