GEOLOGIJA 40, 187-221 (1997), Ljubljana 1998
Biostratigraphy of Shallow Marine Jurassic Beds in
Southeastern Slovenia
Biostratigrafija plitvovodnih jurskih plasti južnovzhodne
Slovenije
Stevo Dozet & Ljudmila Šribar
Geološki zavod Ljubljana
Inštitut za geologijo, geotehniko in geofiziko
Dimičeva 14, 1000 Ljubljana, Slovenija
Key-words: Algae, Foraminifera, biostratigraphy, Jurassic, Outer Dinarides, sou-
theastern Slovenia
Ključne besede: alge, foraminifere, biostratigrafija, jura. Zunanji Dinaridi, ju-
žnovzhodna Slovenija
Abstract
The stratigraphie range of fossils collected from different localities has been stu-
died and used as a basis for biostratigraphic subdivision of Jurassic beds in southe-
astern Slovenia.^On the basis of collected micropaleontological data in the area bet-
ween Logatec, Žužemberk and the river Kolpa, it has been possible to define all
units used for the biozonation of these beds in Outer Dinarides. The following ceno-
zones, which can be recognized throughout the carbonate platform area, have been
determined: Palaeodasycladus mediterraneus, Mesoendothyra croatica, Selliporella
donzella, Salpingoporella (Macroporella) sellii and Clypeina jurassica. Some of the
above-mentioned cenozones are further divided into subzones. A brief correlation
has been carried out among Kočevje shelf lagoon, the Vrhnika-Logatec back-reef
and the Suha Krajina central and fore reef Jurassic sediments and fossils. In the
back-reef area the cenozone Palaeodasycladus mediterraneus with the subzone Or-
bitopsella praecursor, the horizon Dictyoconus cayeuxi and the cenozone Protope-
neroplis striata have been established.
Kratka vsebina
Na mnogih krajih južnovzhodne Slovenije smo zbirali fosilne organske ostanke
in preučevali stratigrafsko razširjenost fosilov, dobljene podatke pa uporabljali za
biostratigrafsko razčlenitev jurske sedimentne skladovnice. Bolj ali manj nepreki-
njeno jursko zaporedje sedimentov v slovenskem delu Zunanjih Dinaridov vsebuje
sorazmerno bogato in pestro favno in floro. V jurski periodi so na obravnavanem
ozemlju nastajale karbonatne kamnine z mikrofavno in floro, hidrozoji, spongijami,
koralami, redkeje s školjkami, polži in brahiopodi.
Z zbranimi mikropaleontološkimi podatki smo dokazali in izločili vse enote, ki
jih uporabljamo pri biostratigrafski razčlenitvi jurskih plasti Zunanjih Dinaridov,
in sicer: Palaeodasycladus mediterraneus, Mesoendothyra croatica, Selliporella
donzella, Salpingoporella sellii in Clypeina jurassica. Nekatere biostratigrafske
188
Stevo Dozet & Ljudmila Šribar
enote so razdeljene v podcone. Nadalje smo primerjali jurske sedimente in fosile ko-
čevske lagune, vrhniško-logaškega zagrebenskega območja ter grebenskega in pred-
grebenskega območja Suhe krajine. V zagrebenskem območju smo ugotovili cenoco-
no Palaeodasycladus mediterraneus s podcono Orbitopsella praecursor, horizont
Dictyoconus cayeuxi in cenocono Protopeneroplis striata.
Introduction
The aim of the present study is to offer a detailed biostratigraphic classification of
the Jurrassic shallow-marine carbonate stratigraphie sequence in southeastern Slo-
venia.
In the years from 1959 tol965S. Buser geologically mapped the territory of south
Slovenia from the Italian-Slovenian border in the west, across Trnovski gozd, Hruši-
ca, Nanos, Logatec and Bloke plateau with Javomiki, Krim-Mokrec hills and Lower
Camiola, to Suha krajina in the east. During this work he collected a rich fossil ma-
terial, and achieved the subdivision of Jurassic beds (B u s e r, 1965).
Fig. 1. Distribution of the Jurassic beds in Slovenia and the location sketch map of the study area
SI. 1. Razširjenost jurskih plasti v Sloveniji in položajna skica ozemlja
The systematic regional mapping of the Slovene territory between Logatec, Žu-
žemberk and the river Kolpa (fig. 1) was carried out in the years between 1960 and
Biostratigraphy of Shallow Marine Jurassic Beds in Southeastern Slovenia_3
1980 within the framework of regional mapping for the Geologic map of Yugoslavia
on the scale of 1:100000. In the study area this enormous project was accomplished
by Bus er (1974), Pleničar & Premru (1977), Bukovac et al. (1984) and
Savie & Dozet (1985) who elaborated geological maps on the scale of 1:100 000
with corresponding explanatory texts. A number of new biostratigraphic and other
geological data were obtained. Further on, Turnšek, Buser and Ogorelec
(1981) described the Upper Jurassic reef complex in the Slovene area. Detailed geolo-
gical investigations have been carried out in the sections Krka-Mali Korinj and
Kompolje-Ogorelec in the Suha Krajina area about 35 kilometres SSE from Ljublja-
na (Strohmenger & Dozet 1991). In these sections the complete stratigraphie
sequence of the Jurassic beds including the contacts between the Upper Triassic and
Lower Liassic as well as the Upper Malm and the Lower Cretaceous is exposed. Fi-
nally, in the framework of regional investigations for the Geologic Map of Slovenia
on the scale of 1:50000 detailed regional mapping of the Suha Krajina region has be-
en carried out by Stevo Dozet and Božo Stojanovič.
On the other hand, the following Serbian and Croatian geologists have made a gre-
at contribution to the Jurassic biostratigraphy in the Outer Dinarides: R a d o i č i ć
(1964,1966,1969,1987), Gušid (1969), Gušić et al. (1971), Velie (1977), N i k 1 e r
& S ok a č (1968).
Not at last the present work is based upon the geological investigations and bio-
stratigraphical knowledge of the Mesozoic beds from the Apennines in Italy. The first
complete biostratigraphical investigations and subdivision of the Mesozoic beds of
the southern Apennines were made by Sartoni and Crescenti (1962). These
were followed by De Castro (1962,1963), Crescenti and Sartoni (1964),
Crescenti (1966), Catenacci, De Castro and Sgrosso (1963). A cor-
relation of the Central Apennines and the Outer Dinarides Jurassic and Cretaceous
beds was executed by Farinacci and R a d o i č i ć (1964). Crescenti (1969)
recognized in the Jurassic and Cretaceous outcrops of the Central Apennines three
principal facies, and defined the litostratigraphic and biostratigraphic units and the-
ir paleogeographical distribution. B u s e r and Debeljak (1994/95) studied the
distribution of lithiotids in the Jurassic beds of south Slovenia. The horizon with bi-
valves (lithiotid horizon) is attributed to Pleinsbachian (Domeñan). The most intere-
sting are three large bivalve species: Lithiotis problematica, Cochlearites loppianus
and Lithiopedalion scutatus. In addition, the following genera can be found: Gervil-
leioperna, Mytilus, Opisoma and Pachyrisma (with subgenera Pachymegalodon and
Durga).
The carbonate rocks are classified according to F o 1 k's (1959) practical pétrogra-
phie classification of limestones. The microfauna and microflora are determined by
the authors of this paper and Rajka Radoičić. Hydrozoans, sponges and corals were
determined by Dragica Tumšek.
Jurassic Bistratigraphy in the Shelf Lagoon Area
In the southeastern part of Slovenia, the Outer Dinarides respectively, comprising
Kočevje, Bela Krajina, Kočevski Rog and the extreme northern part of the Gorski
Kotar area (Croatia), the complete development of Jurassic beds has been revealed.
The 1500 m to 2000 metres thick Jurassic sedimentary succession lies concordantly
upon the Upper Triassic dolomite and continually passes upwards into the Lower
190_Stevo Dozet & Ljudmila Šribar
Cretaceous limestone and dolomite. The Jurassic beds exposed in the area mentioned
consist of shallow-marine carbonate rocks: limestones, dolomites as well as calcareo-
us-, dolomitiC", and calcareous-dolomitic breccias. These carbonate sediments were
formed in various carbonate platform environments, such as intertidal, supratidal,
subtidal, restricted shoals and lagoons. Generally speaking, the Jurassic sedimentary
succession is predominantly built of limestones. The dolomites are subordinated.
Breccias occur in larger quantities at the Lower Malm/Upper Malm and Jura/Lower
Cretaceous boundaries. The bauxite bodies are arranged along the Lower Kimmerid-
gian/Upper Kimmeridgian contact in the form of lenses and funnel-shaped bodies.
Marls, clays, coal and chert appear in extremely subordinate quantities.
On the basis of significant lithofacies and biofacies as well as their superposition
the shallow water Jurassic sedimentary succession was divided into eight lithostrati-
graphic units. They follow from the oldest to the youngest in this way: 1)- grained bi-
tuminous dolomite (Lower Liassic), 2)- lithiotid limestones and dolomites (Middle
Liassic), 3)- spotted limestones (Upper Liassic), 4)- foraminiferal, algal and micritic
limestones (Dogger), 5)- Cladocoropsis limestones and dolomites (Oxfordian and
Lower Kimmeridgian), 6)- bauxite, 7)- Clypeina-Tintinnina limestones and dolomites
(Upper Kimmeridgian and Tithonian), 8)- limestones and dolomites with chert (Up-
per Kimmeridgian and Tithonian).
From the biostratigraphic point of view, the Jurassic sedimentary successions of
the Kočevje area and the whole shelf lagoon area in southeastern Slovenia are subdi-
vided by algae and foraminifers into five cenozones and three subzones. The biostra-
tigraphic subdivision is comparable with the chronostratigraphic one.
Lower and Middle Liassic - Cenozone Palaeodasycladus mediterraneus
The Upper Triassic cryptocrystalline and stromatolitic dolomite with rare oncoids,
foraminifers and megalodontids grades upwards into the dark-gray, coarsely crystal-
line, bituminous late diagenetic dolomite containing lithiotids in its upper part, or
into the dark-gray shallow-marine limestones alternating with dolomites. The main
lithologie characteristics of the Middle Liassic successions is - in addition to lithiotid
horizons - the alternation of oolitic, intraoosparitic, and dolomitic layers. Generally
speaking, in southern Slovenia three lithologie developments of the Lower and Mid-
dle Liassic are distinguished: dolomitic, calcareous-dolomitic, calcareous.
The cenozone Palaeodasycladus mediterraneus was established by Sartoni
and Crescenti (1959) comprising originally the whole Liassic. In the Slovenian
part of the Dinarides, its appartenance has been proved only in relation to the Lower
and Middle Liassic. The Lower and Middle Liassic beds are usually rather rich in
fossil remains (Plate 1). Among the most important ones are lithiotids.
Lithiotids are very widespread, easily recognizable and relatively well-preserved
megafossils with a limited (Middle Liassic) chronostratigraphic range; for this reason
we consider them the most convenient fossils for designation of Middle Liassic in the
Outer Dinarides.
Within the framework of the Palaeodasycladus mediterraneus cenozone the subzo-
ne Orbitopsella praecursor Guembel (Middle Liassic) is separated and distinguished
by the following fossil association:
Foraminifers: Orbitopsella praecursor Guembel (Plate 1/3), Mayncina termieri
Hottinger, Haurania amiji Henson, H. deserta Henson, Litousepta recoarensis Cati,
Biostratigraphy of Shallow Marine Jurassic Beds in Southeastern Slovenia_191
Orbitopsella sp., Involutina sp., Trocholina sp., Frondicularia sp., Verneuilinidae, Mi-
liolidae, Textulariidae, Lituolidae.
Algae: Palaeodasycladus mediterraneus (Pia) (Plate 1/2), Thaumatoporella parvo-
vesiculifera (Raineri), Codiaceae.
Lithiotids: Lithiotis problematica Guembel, Cochlearites loppianus.
Upper Liassic - Zone of spotted limestones
The upper part of the Liassic sedimentary succession includes spotted limestones
characterized by lithologie uniformity and lack of fossils. The Upper Liassic shows
the same development throughout the carbonate platform area. These beds are com-
posed of micritic limestones intercalated with oomicritic and intramicritic ones. The
spotted limestones are characterized by numerous spots as a result of irregular mine-
ral and chemical rock composition, selective late diagenetic dolomitization of lime-
stones, bioturbation, decolourized iron, and different contents of clay and organic
substances. In the considered beds, fossil remains are very rare. They belong to bio-
stratigraphically insignificant foraminifers, Algae, ostracods, microgastropods, and
other molluscs. The characteristics of the sediments indicate a deposition in a so-
mewhat deeper restricted shelf environment.
The described succession of limestones lies everywhere in the Kočevje area confor-
mably upon Lithiotid limestones, and it is conformably overlain by sediments with
guide Dogger microfossils. Thus, its stratigraphie position is clear, although the li-
mestones do not contain index fossils.
Lower Dogger - Cenozone Mesoendothyra croatica
The Lower Dogger beds are uniformly developed in the form of micritic limestones
with rare interlayers of biomicrites and grained bituminous dolomite, especially in
the lower part of the succession. Among the biomicritic limestones the foraminiferal
ones predominate.
Mudstone and wackestone sedimentary structures and law energy index indicate a
calm sedimentation in the shallow restricted shelf, or lagoon. The interlayers of in-
traformational breccia and biointrasparitic limestones point to a temporary agitated
environment with a relatively high energy index and periodical influences from the
open sea.
The Mesoendothyra croatica cenozone comprises calcareous beds with the follo-
wing association:
Foraminifers: Mesoendothyra croatica Gušić, Verneuilinidae, Textulariidae, Glo-
mospira sp..
Algae: Thaumatoporella parvovesiculifera (Raineri), Codiaceae and other fossils
such as Favreina salevensis (Paréjas), Echinodermata, ostracods and microgastropods.
Upper Dogger - Cenozone Selliporella donzella
The Upper Dogger sedimentation is very similar to the one from the Lower Dogger,
additionally including interlayers of intraformational breccia and algal biointraspa-
192_Stevo Dozet & Ljudmila Šribar
rite. The relatively uniform sedimentation of micritic, pelmicritic and biopelmicritic
sediments indicates that the Upper Dogger beds were formed in the predominantly
calm and shallow water of the restricted shelf or even in a lagoon. On the other hand,
rare thin intraclastic and breccia interbeds were formed in short periods when inter-
tidal and shallow subtidal conditions predominated.
The Upper Dogger beds are generally more rich in fossils than the Lower Dogger
ones, and contain the following fossil association:
Algae: Selliporella donzella Sartoni & Crescenti, Thaumatoporella parvovesiculi-
fera (Raineri), Cyanophyta.
Foraminifers: Meyendorfina bathonica Aurouze & Bizon, Trocholina elongata (Le-
upold), Pfenderina salernitana Sartoni & Crescenti (Plate 2/4), P. cf. neocomiensis (De
Castro), Protopeneroplis striata Weynschenk, Pfenderina sp., Endothyra sp., Nodosa-
ria sp., Favreina sp., Verneuilinidae, Textulariidae, Lituolidae as well as Ostracoda,
and Echinodermata.
Lower Malm - Cenozone Salpingoporella sellii
Concordantly on the Dogger foraminiferal, algal and micritic limestones rest in
the study area limestones and dolomites characterized by mass appereance of hydro-
zoan Cladocoropsis mirabilis Felix (Plate 4/1-2). The most significant facies of the
succession are Cladocoropsis limestones and dolomite as well as foraminiferal, algal,
brachiopod and oncolitic limestones. In the lower part of this sedimentary succession
micritic, biomicritic and biosparitic limestones alternate. In the middle part of the
succession biocalcarenites are predominant. At some places there are minor parastro-
matoporoid patch reefs and lenses of oolitic and oncolitic limestones. In the whole
succession limestones are predominant.
On the basis of the determined macrofauna, microfauna and flora the Malm beds
have been divided into two parts: The lower part comprises the Oxfordian and Lower
Kimmeridgian, and the upper one includes the Upper Kimmeridgian and Tithonian.
Limestones, dolomites and calcareous breccias of the lower part of Malm have been
assigned to the Salpingoporella sellii cenozone. This biostratigraphic unit is well do-
cumented with Algae, foraminifers and megafossils.
Algae: Salpingoporella {=Macroporella) sellii (Crescenti), plate 3/1-2, Gryphopo-
rella minima Nikler & Sokač, Salpingoporella annulata Carozzi, Thaumatoporella
parvovesiculifera (Raineri), Aeolisaccus dunningtoni Elliot, Codiaceae, Cyanophyta.
Foraminifers: Nautiloculina oolithica Möhler, Kurnubia palastiniensis Henson,
Protopeneroplis striata Weynschenk, Labyrinthina mirabilis Weynschenk, Pfenderina
salernitana Sartoni & Crescenti, Pfenderina trochoidea Smouth & Sugden, Trocholi-
na elongata (Leupold), plate 3/3-4, Trocholina alpina (Leupold), Verneuilinidae, Bio-
kovinidae, Textulariidae and Lituolidae.
Hydrozoans: Cladocoropsis mirabilis Favre, Shuqraia arrabidensis.
Anthozoans: Microphyllia bachmayeri Geyer, Convexastraea sexradiata (Gold-
fuss), Rhipidogyra cf. alata (Quensted), Acanthogyra miera Eliašova, Montlivaltia
sp., Epistreptophyllum tenue Milaschewitsch.
The hydrozoans and corals were determined by Dragica Tumšek.
Biostratigraphy of Shallow Marine Jurassic Beds in Southeastern Slovenia_7
Upper Malm - Cenozone Clypeina jurassica
The upper part of the Malm succession is uniformly developed in the whole study
area. It consists of limestones, dolomites and calcareous-dolomitic breccias. The Up-
per Malm succession begins usually with intrasparruditic limestone or intraformatio-
nal breccia. The most frequent sediments in the succession are Clypeina limestones
and dolomites. In the upper part of the succession intensely dolomitized limestone
and dolomite are frequent. In the uppermost part of the succession the beds with
aberrant tintinnins predominate. The Clypeina, Clypeina-Tintinnina (Plate 6, 7/1-2)
and Tintinnina limestones and dolomites are the most typical facies of this unit.
In spots, in the upper part of the Upper Malm succession there occur limestones
and dolomites with oval, lenticular, rarely irregular chert concretions. The chert no-
dules in limestones and dolomites are of diagenetic origin. They were probably for-
med in still unconsolidated carbonate mud by the action of the silica-rich solutions
on carbonate, where the carbonates were substituted by silica.
The Upper Malm beds of the Kočevje, Bela Krajina and Gorski Kotar area were
formed on the vast carbonate platform in the shallow waters of subtidal, intertidal,
supratidal and lagoonal environments. The presence of the organic substance in the
sediments indicates a reducing environment. Intraformational conglomerate, and bi-
olaminated limestones and dolomites with nodules and lenses of chert were formed in
the intertidal and supratidal environments. The beds of limestones and dolomites
with nodules and lenses of chert were formed in a lagoon or in a shallow subtidal en-
vironment.
Limestones and calcareous dolomites contain a relatively rich microfossil associa-
tion with the following Algae, foraminifers and other fossils.
Algae: Clypeina jurassica Favre (Plate 5/1-4), Salpingoporella (Pianella) grudii
(Radoičić), Salpingoporella annulata (Carozzi), Actinoporella podolica Alth, Thau-
matoporella parvovesiculifera (Raineri), Cyanophyta, Charophyta and Codiaceae.
Foraminifers: Kurnubia palastiniensis Henson, Trocholina elongata (Leupold),
Trocholina alpina (Leupold), Pseudocyclammina lituus (Yokoyama), plate 7/4, Verne-
uilinidae, Lituolidae, Biokovinidae, Textulariidae, Opthalmidiidae, Miliolidae.
Aberrant tintinnids: Campbelliella milesi milesi Radoičić (Plate 8).
Gastropods: Nerinea jeanjeani Roman, Ptygmatis minuta Yin as well as fossils
Favreina salevensis (Paréjas), Echinodermata and ostracods.
Correlation between the Shelf Lagoon and Reef Complex Sedimentation,
Biostratigraphy and Paleogeography in Southeastern Slovenia
Three different sedimentary areas in southern Slovenia are considered and correla-
ted in this paper: 1 - the carbonate platform area (Kočevje, Bela Krajina, Kočevski
rog, Gorski Kotar), 2 - the back-reef area (Vrhnika, Logatec plateau, southern Suha
Krajina, and 3 - central and fore reef area (northern Suha Krajina, Novo mesto, Me-
tlika).
In the relatively small region of southern Slovenia Turnšek (1969) recognized
three types of hydrozoan fauna which were connected with the three mentioned are-
as: the hydrozoan Cladocoropsis in the southern faunistic area, the parastromatopo-
ridian hydrozoans, corals, and chaetetids in the central faunistic area, and the acti-
nostromaridian hydrozoans in the northern faunistic area. These different types had
194
Stevo Dozet & Ljudmila Šribar
developed due to the different ecologie conditions prevalent in each of these areas.
The areas with individual faunistic types follow each other in narrow and long belts
extending from the southwest to the northeast.
Generally speaking, in the Jurassic beds of the study area in southeastern Slovenia
five particular facies are recognizable: shelf lagoon facies, back-reef bioclastic and
oolitic facies as well as organic reef facies (central reef) and fore reef facies.
In the Lower Liassic there was a constant shelf lagoon sedimentation all over the
area of southeastern Slovenia. The significant differentiation of the Dinaric carbona-
te platform (fig. 2) environment began there in the Middle Liassic. The back-reef fa-
cies had its beginning after the shelf lagoon sedimentation in the Middle Liassic. The
reef sedimentation began and ended there in the Malm period.
Fig. 2. Paleogeographic map of the Jurassic beds in the study are
SI. 2. Paleogeografska karta jurskih plasti obravnavanega ozemlja
The Shelf Lagoon Area
In inner parts of the Dinaric carbonate platform in the Kočevje, Bela Krajina and
Gorski Kotar area the carbonate platform shelf lagoon facies existed. It has been al-
ready described in detail (R a d o i č i c, 1966, 1969; В u s e r, 1974, 1978; P 1 e n i č a r,
1970; Dozet & Š r i b a r, 1981; Bukovac et al., 1984; Savie & Dozet,
1985; Dozet, 1990, 1993, 1996; and Strohmenger & Dozet, 1991). Howe-
Biostratigraphy of Shallow Marine Jurassic Beds in Southeastern Slovenia_195
ver, it is necessary to emphasize the continuity and diversity of the sedimentation
there. It w^as most extensive in Lower and Middle Liassic comprising the whole sou-
thern Slovenia. Very interesting is the Lower Liassic limestone development at Krka
in the Suha Krajina area (Dozet, 1993) composed of shallow water lagoonal lime-
stones formed in subtidal, intertidal, and supratidal environments. The succession is
characterized by predominantly dark grey carbonate sediments among which micri-
tic, biomiciritic, oomicritic and oncomicritic limestones prevail. The main characteri-
stics of Krka limestones is the well-developed rhythmic sedimentation. The cycles are
composed of three members such as cyclothems in the type locality Loferer Steinber-
ge (F i s h e r, 1964).
The Krka limestone succession with Lofer cyclic sedimentation lies concordantly
between the Upper Triassic Hauptdolomit and the Middle Liassic beds with lithio-
tids. The stratigraphie position of the Krka limestones points to their Lower Liassic
age. Their age is also confirmed by the fossils: Palaeodasycladus mediterraneus Pia,
P. elongatus Praturlon, Linoporella lucasi Gros & Lemoine, Thaumatoporella parvo-
vesiculifera (Raineri), Gyroporella sp., Palaeodasycladus sp., and Codiacea as well as
fossils Favreina salevensis Paréjas, Textulariidae, and Verneuilinidae. Besides the
microfauna and microflora, megalodontids and gastropods also appear in the consi-
dered beds.
The Back-Reef Area
The back-reef sedimentation in southeastern Slovenia is represented by oolitic and
bioclastic calcarenites which are most typically developed at Vrhnika and in the sou-
thern Suha Krajina area. Tidal-bar oolitic limestones are massive to thick-bedded.
They consist of well-sorted ooids, well-rounded intraclasts, and fossil detritus sho-
wing in spots clear graded bedding and cross-bedding. Stromatoporoid hydrozoans,
chaetetids, corals, echinoids, bryozoans, pelecypods and benthic foraminifers occur
sporadically in the oolitic limestones. In the limestones coated bioclasts are quite fre-
quently encountered. The sedimentologie features in the limestones point to a trans-
port of the clasts in a rather agitated environment. The fossil contents in the limesto-
nes indicate the existence of small patch reefs. Numerous echinoid fragments also in-
dicate the proximity to reefs. Oolitic limestones have a thickness of some hundred
metres. The oolitic limestones at Vrhnika are of the Middle Liassic to the Lower Kim-
meridgian age.
Winnowed edge bioclastic limestones are rocks consisting of fragmental and bro-
ken remains of Malm reef-building organisms and calcitic cement. Larger limestone
and megafossil fragments and minor arenitic microfossil ones are the main constitu-
ents of the limestones. The fragments mostly originate from the Jurassic hydrozoans,
sponges, corals, Algae, echinoids, gastropods and other molluscs, as well as bryozo-
ans. From the structural point of view the bioclastic limestones are represented by
intrabiosparites in which a strong recrystallization of fossils and fragments of areni-
tic size is present. Predominantly micritic intraclasts are strongly recrystallized. Also
the original matrix is recrystallized. Bioclastic sediments are usually massive to we-
akly stratified. In spots, the limestones pass laterally and vertically into dolomites
formed by a selective late diagenetic dolomitization of the limestones.
The back-reef biostratigraphy differs from the carbonate platform one and is only
partly applicable there. In the Jurassic back-reef sedimentary succession the folio-
196
Stevo Dozet & Ljudmila Šribar
Table 1. Biostratigraphic subdivision of the back-reef Jurassic beds in the southeastern Slovenia
Tabela 1. Biostratigrafska razčlenitev zagrebenskih plasti južnovzhodne Slovenije
v^^ing biostratigraphic units (table 1) are defined (from bottom to top): 1 - Cenozone
Palaeodasycladus mediterraneus Pia, 2 - Dictyoconus cayeuxi Lucas horizon, 3 - Ce-
nozone Protopeneroplis striata Weynschenk.
Lower and Middle Liassic - Cenozone Palaeodasycladus mediterraneus
The cenozone Palaeodasycladus mediterraneus (Pia) with the Orbitopsella prae-
cursor (Guembel) subzone was first described in the southern Apennines in the Veni-
Biostratigraphy of Shallow Marine Jurassic Beds in Southeastern Slovenia_11
ce and Trento districts by Sartoni and Crescenti (1959). The biozone was
ascribed to the Liassic, and the subzone to the Middle Liassic.
In the Dinaric carbonate platform area this cenozone corresponds to the stratigra-
phie range of alga P. mediterraneus (Pia) comprising the Lower and Middle Liassic.
In the oolitic limestones of the back-reef area, only the upper part of the P. mediter-
raneus cenozone is presented which is of the Middle Liassic age. In the middle part of
the cenozone the Orbitopsella praecursor subzone is defined. The Middle Liassic se-
dimentary succession contains numerous microfossils among which predominate fo-
raminifers: Orbitopsella praecursor (Guembel), Lituosepta recoarensis (Cati), Ageri-
na mariana (Farinacci), Orbitopsella sp., Glomospira sp., Textulariidae, Ophthalmi-
diidae, Verneuilinidae, and Lagenidae.
In addition to foraminifers there also appear Algae: Paleodasycladus mediterrane-
us Pia, Thaumatoporella parvovesiculifera (Raineri), Palaeodasycladus sp., Cyanoph-
yta, Codiaceae and blue-green algae. Rarely found are the species Favreina salevensis
(Paréjas) and fragments of alga Aeolisaccus sp. In addition to foraminifers and Al-
gae, remains of hydrozoans, bryozoans, corals, ostracods, echinoids and molluscs can
also be found.
Dogger - Dictyoconus cayeuxi horizon
The horizon D. cayeuxi was considered by Crescenti (1969) as coinciding
with the stratigraphie range of the foraminifera Dictyoconus cayeuxi Lucas. In the
Outer Dinarides area it is referable to the Dogger. It is characterized by the following
microfossils:
Foraminifera: Dictyoconus cayeuxi Lucas, Spiraloconulus perconigi Allemann &
Schroeder, Nautiloculina oolithica Möhler, Mesoendothyra croatica Gušić, Mesoen-
dothyra sp., Trocholina sp., Protopeneroplis sp., Evertycyclammina sp., Frondicula-
ria sp., Verneuilinidae, Textulariidae, Miliolidae, Trochaminidae, Lituolidae and
Ophthalmidiidae.
Algae: Selliporella donzella Sartoni & Crescenti, Thaumatoporella parvovesiculi-
fera (Raineri), Cyanophycea, Codiacea.
Ostracods, corals, gastropods and other molluscs as well as bryozoans.
Dogger and Lower Malm - Cenozone Protopeneroplis striata
This cenozone is most characteristic of the oolitic facies in the back-reef area. It
was established by Sartoni and Crescenti (1962), its lower limit being
marked by the extinction of Dictyoconus cayeuxi as well as by the appearance of
Protopeneroplis striata. The cenozone is relatively rich in microfossils, especially
foraminifers, among which the species P. striata is of major extent and importan-
ce.
Foraminifera: Protopeneroplis striata Weynschenk (Plate 2/2-3), I^abyrinthina mi-
rabilis Weynschenk, Nautiloculina oolithica Möhler, Trocholina elongata (Leupold),
Trocholina alpina (Leupold), Kurnubia palastiniensis Henson, Pfenderina sp., Proto-
peneroplis sp., Trocholina sp., Lepidocyclina sp., Frondicularia sp., Cristelaria sp.,
Lituolidae, Textulariidae, Verneuilinidae, Miliolidae, Lagenidae.
Algae: Salpingoporella annulata Carozzi, Heteroporella anici Nikler & Sokač,
198_Stevo Dozet & Ljudmila Šribar
Thaumatoporella parvovesiculifera (Raineri), Palaeosyphonium convolvens (Pratur-
lon), Solenopora jurassica (Nicholson).
In addition to microfossils there also appear some megafossils:
Hydrozoans: Cladocoropsis mirabilis Felix (Plate 4/1-2), Dehornella omanensis
Hudson, D. crustans Hudson, Milleporidium remesi, Parastromatopora japónica Yabe
& Sugiyama, P. memoria naumanni Yabe & Sugiyama, Shuqraia zuffardii.
Chaetetids: Acanthochaetetes foroiuliensis (Zuffardi & Comerci), Bauneia multita-
bulata (Deninger), Chaetetopsis crinita (Neumayr).
Corals: Allocoenia trochiformis Etallon, Calamophylliopsis moreauana Michelin,
Comoseris baltovensis Roniewicz, Meandrophyllia amedei Etallon, Meandrophillia
edwardsi (Michelin), Microsolena thurmanni Koby, M. agariciformis (Etallon), Helio-
coenia orbigny Roniewicz, Heliocoenia variabilis Etallon, Pseudocoenia variabilis, P.
limbata (Goldfuss), P. longiseptata Roniewicz, Plesiosmilia compressa (Koby), Puha-
straea kamiennae Roniewicz, Stylosmilia corallina Koby, Stylosmilia pumila, Tha-
mnasteria concanna Goldfuss, Pleurophyllia sp., Enhalhellia sp., Thamnasteria sp.,
Halisitastraea sp. as well as bryozoans, echinoids and molusc.
Central and Fore Reef Area
In the Jurassic period on the Dinaric carbonate platform a shallow water shelf sedi-
mentation was established. The sedimentation was continuous, if we exclude the local
short-lasting interruption on the Lower Malm-Upper Malm transition, when in periods
of the short land phase thin bauxite deposits were formed. On the other hand, in the
transition area between the shelf and the Slovenian trench, orogenetic activity was pre-
sent, causing the lifting of the marginal parts of the Dinaric carbonate platform, thus
forming dry land at the end of the Middle Liassic. With the formation of the dry land
the sedimentation was completely interrupted there and such conditions were preser-
ved until the Lower Malm. The Middle Liassic-Lower Malm stratigraphie gap is
proved by the absence of the Lower Liassic and Dogger sediments. On the other hand,
an erosional-tectonic discordance between the Triassic-Liassic succession and the reef
sediments points to orogenic movements in that interval, which we connect with the
movements of the Mesokimmerian orogenic phase (Tollmann, 1966). The conside-
red stratigraphie gap is an evident proof of an emersion after the deposition of the Mid-
dle Liassic beds which lasted until the Lower Malm transgression. The mentioned Mid-
dle Liassic-Lower Malm emersion was not a local phenomenon, for it has been obser-
ved and proved in several parts of the Slovenian, Croatian and Bosnian Dinarides. (T u
rnšek, 1969; B u s e r, 1974; Bukovac et al., 1974; Š p a r i c a, 1981; Dozet,
1989, 1994). The above-mentioned authors and others emphasized that the paleogeo-
graphical and structural changes which appeared in the Dinarides after the deposition
of the Middle Liassic beds, were expressed by the Middle Liassic-Lower Malm strati-
graphic gap. In that time interval some areas in the Outer Dinarides were completely
without sedimentation, and are understood paleogeographically as a bar with greater
and minor elevations. They could be interpreted as a part of a uniform island chain ex-
tending from Bosnia Krajina, over Kordun, Banija, Žužemberk, Bela krajina, Suha
krajina, Trnovski gozd, onward to the northwest. This morphologically well-exposed
narrow bar was in the closest connection with the differentiation of the sedimentary
areas on the - by that time uniform - Dinaric carbonate platform. Malm hydrozoan-co-
ral reefs were also formed. The reef complex is thought to be a barrier-reef that develo-
Biostratigraphy of Shallow Marine Jurassic Beds in Southeastern Slovenia_13
ped along the shelf margin of an ancient carbonate platform (Turnšek, Buser &
Ogorelec, 1981). It should be recalled that in the inner carbonate platform area no
tectonic movements occurred in the Mesozoic period (Dozet, 1989), because no fol-
ding, thrusting or nappe-tectonic traces, traces of volcanism or metasomatic changes
on sedimentary rocks in that time can be found there. Nowhere any tectonic-discordant
contacts can be seen; on the contrary, in all cases concordance or at most only light di-
scordance is dealt with. In the carbonate platform area also no coarse-grained basal
transgressive formations can be found so that we are right in affirming that the conti-
nuity of sedimentation was disturbed only by the periodical interruptions as a reflec-
tion of weak or stronger epeirogenic movements of the carbonate platform. These mo-
vements gave rise to periodical land in the Mesozic; they also affected the differentia-
tion of the environment and in this way had a considerable influence on the sedimen-
tation.
Relatively continuous sedimentation - though of another type - also occurred all
over the Jurassic period in the areas of the Dinaric carbonate platform near to the
bar, i.e. in the back-reef areas.
The central and fore reef area is built by sediments the main constituents of which
are fossils or their fragments. Consequently, the considered sedimentation is repre-
sented by organic biolithitic limestones and fore reef breccias.
The organic reef is composed of light gray, medium gray, gray, rarely dark gray bi-
olithitic limestones. Biolithitic limestones are unstratified rocks of the calcareous re-
mains of reef-building organisms cemented by calcium carbonate. The central reef
was built by Jurassic reef-building organisms such as hydrozoans, sponges, corals,
bryozoans, chaetetids. Algae, gastropods and other molluscs and echinoids. The rela-
tively numerous bioherms and the extension of the reef carbonate rocks in southea-
stern Slovenia indicate reefs of barrier type. In the basal part of the reef limestones
there are gray, dark gray, thick-bedded limestones with nodules, lenses and thin la-
yers of chert. The reef limestones have a thickness of 400 m to 550 m. Hydrozoans
were the main reef-building organisms there. Among the hydrozoans the predomi-
nant family is Sphaeractinidae with genres Sphaeractinia and Ellipsactinia, but the-
re are also numerous other hydrozoans of Actinostromariicea. Therefore Turnšek
(1966, 1969) named the hydrozoans of the northern area as the actinostromarid type.
Chaetetids, corals and pelecypods are rare there. The form of the colonies, the great
amount of the reef-building fauna, and the structure of the sediments indicate that
this northern faunistic area was a true reef formation. Because of the great prevalen-
ce of the hydrozoan fauna, Turnšek (1966, 1969) even called it the hydrozoan reef.
This actinostromarid reef formed a reef barrier that represented the border between
the shelf and the deeper sea.
Fore reef breccias are sedimentary rocks formed by the consolidation of fragments
of Jurassic limestone and reef-building organisms broken off from reefs by the action
of waves. In the rocks the most frequent fragments are those of hydrozoans, corals
and pelecypods. They are cemented by calcitic cement.
Conclusions
Three different paleogeographic and sedimentary areas are considered and in some
way correlated in this paper; these are: the shelf lagoon area, the back-reef area, as
well as central reef and fore reef areas. Likewise, in the Jurassic outcrops of southea-
200_Stevo Dozet & Ljudmila Šribar
stern Slovenia, generally five different facies are recognizable: shelf lagoon facies,
oolitic facies, bioclastic facies as well as organic reef and fore reef facies.
Biostratigraphically, the area studied in greatest detail is the carbonate platform
in the Kočevje area. Five cenozones and three subzones are present there; these are:
Palaeodasycladus mediterraneus, Mesoendothyra croatica, Selliporella donzella,
Macroporella sellii and Clypeina jurassica (cenozones); Orbitopsella praecursor,
Clypeina jurassica, and Clypeina jurassica + aberrant tintinnids (subzones). The ce-
nozone Palaeodasycladus mediterraneus covers the Lower and Middle Liassic. Due
to the lack of significant fossils, the zone of the platy dolomites (Lower Liassic) and
the zone of spotted limestones (Upper Liassic) were separated. The cenozone Mesoen-
dothyra croatica covers the lower part of the Middle Jurassic succession while the ce-
nozone Selliporella donzella covers the upper one. For the carbonate platform in the
Slovenian part of the Outer Dinarides the bipartite subdivision of the Malm successi-
on is proposed: the cenozone Salpingoporella sellii, covering the lower part of the
Malm, and Clypeina jurassica representing the upper part of Malm.
In the Jurassic sedimentary succession of the back-reef area three following bio-
stratigraphic units have been defined. The cenozone Palaeodasycladus mediterrane-
us, the Dictyoconus cayeuxi horizon, and the cenozone Protopeneroplis striata. As in
the inner carbonate platform, in the back reef area the cenozone Palaeodasycladus
mediterraneus comprising Lower and Middle Liassic was established. The horizon
Dictyoconus cayeuxi appears in Dogger. Finally, the third biostratigraphic unit, the
Protopeneroplis striata cenozone includes the uppermost part of Dogger and Lower
Malm.
Acknowledgements
The authors are most grateful to Dr. Dragica Tumšek for the determination of
hydrozoans, sponges, corals and chaetetids and to Dr. Rajka Radoičić for determina-
tion of several microfossils and valuable suggestions. Appreciation is expressed to
Prof. Dr. Mario Pleničar and Prof. Dr. Stanko Buser for critical review of the manu-
script and to Prof. Dr. Simon Pire for his revision of the translation into English. For
technical assistance in drafting and typing we would like to thank Ms. Metka Karer
and Ms. Marjeta Oman.
Biostratigrafija plitvovodnih jurskih plasti južnovzhodne Slovenije
Sklep
Jurske plasti so poleg triasnih najbolj razširjene kamnine obravnavanega ozemlja.
Skladovnica jurskega apnenca in dolomita leži konkordantno na zgomjetriasnem do-
lomitu; prehod iz zgomjetriasnega stromatolitnega dolomita v zmati bituminozni
jurski (liasni) dolomit je postopen. Med Krko in Zagradcem predstavlja spodnjeliasne
plasti apnenčev razvoj, kontakt z glavnim dolomitom pa je oster. Spodnjeliasni Krki-
ni apnenci so plastnati, temno sivi do čmi. V strukturnem pogledu prevladujejo mi-
kriti in biomikriti z algami. V spodnjeliasnih apnencih je med drugim najdena in do-
ločena tudi alga Palaeodasycladus mediterraneus Pia. Poleg omenjenih se v spodnje-
Biostratigrafija plitvovodnih jurskih plasti južnovzhodne Slovenije_
liasnem zaporedju pojavljajo še oomikritni, intrasparitni in biointrasparitni apnenci
z vložki intraf ormaci j skih breč in konglomeratov, fenestralnih apnencev, stromatoli-
tnih apnencev, tu in tam dolomitov. Našteti sedimenti kažejo izrazite plitvomorske
karakteristike in so nastajali v podplimskem, medplimskem in nadplimskem okolju.
Srednjeliasna sedimentacija je bila precej bolj pestra kot spodnjeliasna. Srednjelia-
sno sedimentno zaporedje sestoji iz zrnatih dolomitov, intraformacijskih dolomitnih
breč, biopelmikritnih, oosparitnih, oointrasparitnih ter litiotidnih in megalodonti-
dnih apnencev. Gre za eno najbolj tipičnih jurskih formacij, ki obsega pestro zapore-
dje karbonatnih sedimentov, katerim skupna značilnost je vsebnost litiotid. Litiotide
so ponavadi nakopičene v obliki lumakel: V spodnjem delu so lumakele redkejše in
tanjše ali pa najdemo le posamične preseke in litiotidne odlomke. Litiotidni apnenci
so temno sivi do sivkasto črni biomikriti, redkeje biospariti. So debeloplastnati, sla-
bo plastnati ali celo masivni. V spodnjem delu litiotidne enote se pogosto pojavljajo
biointrasparitni, oosparitni in biomikritni apnenci z orbitopsellami in drugimi mi-
krofosili, niso pa tudi redki vložki dolomita. V litiotidni formaciji prevladuje bio-
stromni tip sedimentacije, zrnati apnenci in dolomiti pa so nastajali predvsem v pli-
tvem podplimskem, medplimskem in tudi nadplimskem okolju. V srednjeliasnih pla-
steh južnovzhodne Slovenije so bogata nahajališča značilnih školjk, ki so v pliensba-
chiju in toarciju množično poselile obsežne med seboj povezane plitvomorske predele
Dinarske karbonatne platforme. Najzanimivejše so tri vrste velikih školjk (B u s e r
& Debeljak, 1994/95): Lithiotis problematica, Cochlearites loppianus in Lithio-
pedalion scutatus. Poleg teh najdemo v srednjeliasnih apnencih še druge rodove, ka-
kor npr. Gervilleioperna, Mytilus, Opisoma in Pachyrisma (s podrodovoma Pachyme-
galodon in Durga).
Zgornjeliasne plasti se pojavljajo v obliki nekaj deset metrov debelega pasu. Odgo-
varjajo formaciji marogastih apnencev. Gre za sive do sivkasto čme mikritne in di-
smikritne apnence z redkimi ostanki alg in foraminifer. V mikritno osnovo so bili z
valovi in tokovi naneseni bolj ali manj številni ooidi, pseudoooidi, onkoidi ali intra-
klasti. Med teksturnimi oblikami opazujemo v teh apnencih le rahlo, zelo drobno la-
minacijo. Po strukturnih in tekstumih posebnostih obravnavanih sedimentov sklepa-
mo, da so se le-ti oblikovali v zatišnem delu šelfa, okolje pa je moralo biti za žive or-
ganizme precej neugodno. Po stratigrafski legi sodeč, je opisano zaporedje sedimen-
tov zgornjeliasne starosti. Leži namreč med litiotidnimi apnenci in doggerskimi ooli-
tnimi apnenci.
Konkordantno na marogastih apnencih leže foraminifemi, algni in mikritni
apnenci, med katerimi prevladujejo temno sivi mikritni apnenci z vložki foraminifer-
nih in algnih biomikritnih apnencev. V spodnjem delu skladovnice prevladujejo med
apnenci biomikriti z mezoendotirami, v zgornjem delu pa biomikriti s selliporelami.
Zgomjedoggersko skladovnico sestavljajo apnenec, apnenčeva breča in dolomit. Opi-
sano zaporedje je običajno revno s fosili. Sedimentne oblike in posebnosti spodnje-
doggerskih kamenin kažejo na pretežno mimo sedimentacijo v plitvem zaprtem šelfu,
ponekod tudi v plitvih lagunah.
Sem in tja so se na prehodu iz liasne v doggersko dobo sedimentaci]ske razmere
močno spremenile, kljub temu pa se je karbonatna sedimentacija še naprej nadalje-
vala. Nad marogastimi apnenci leži več kot sto metrov debela skladovnica temno si-
vih, sivkasto čmih in črnih, redkeje sivih oolitnih apnencev, v katerih so našli spo-
dnjedoggersko in srednjedoggersko mikrofavno in floro. V strukturnem pogledu gre
za srednjezrnate oosparitne in intraoosparitne apnence, ki se ločijo od spodnjemal-
skih oolitnih apnencev po temnejši barvi in po tem, da ne vsebujejo grebenske favne.
202_Stevo Dozet & Ljudmila Šribar
Povečini gre za dobro sortirane in izprane sedimente, ki vsebujejo v glavnem le redke
odlomke fosilov. V glavnem gre za foraminifere. Največ mikrofavne in flore sledimo v
tankih vložkih sivih in temno sivih biomikritov.
Lagunske plasti spodnjega dela malma so litološko zelo pestre. Njihovo zaporedje
se ponavadi prične s srednje sivim in sivim plastnatim sparitnim, mikritnim in bio-
mikritnim apnencem, ki so bolj ali manj dolomitizirani. Navzgor sledi temno sivi in
čmi plastnati apnenec, ki pripada različnim strukturnim tipom. Za ta del zaporedja
so ponekod značilne lumakele z brahiopodi in vložki dolomita s cladocoropsisi. V vr-
hnjem delu zaporedja prevladujejo biokalkareniti, ponekod pa so ugotovljeni tudi
manjši grebeni in leče oolitnega in onkoidnega apnenca. V spodnjem in srednjem delu
obravnavanega sedimentnega zaporedja so tanj še in debelejše partije drobno-, sre-
dnje- in debelozmatega, nekoliko bituminoznega dolomita. Spodnjemalmsko zapore-
dje sedimentov zaključujejo plasti intraformacijskega konglomerata in breče. Našteti
sedimenti so ponavadi jasno plastnati in ponekod laminirani ali celo stromatolitni.
Straktura je zelo drobnozmata, arenitna in ruditna. V struktumem pogledu ločimo
mikritne, biomikritne, pelmikritne, intrasparitne, biointrasparitne in dmge prehodne
oblike. Opisane spodnjemalmske plasti so se oblikovale na obsežni karbonatni plat-
formi v mirni vodi plitvih lagun ter v med- in podplimskem pasu. Tu se je usedalo
apnenčevo blato, iz katerega je nastal mikrit. Okolje je bilo ugodno predvsem za ra-
zvoj alg in foraminifer, manj za druge organizme. Od časa do časa so nastopile ugo-
dne razmere za rast spongij, brahiopodov, školjk in polžev. S kopičenjem njihovih
skeletov so ponekod nastale lumakele, ki so se ohranile v obliki tanjših vložkov zno-
traj spodnjemalmske skladovnice.
Oolitne apnence srečujemo v juri že v srednjeliasnih plasteh, vendar se tu pojavlja-
jo le v obliki tanjših ali debelejših vložkov. Nekaj sto metrov debelo skladovnico ooli-
tnih apnencev pa imamo v spodnjem delu malmskih plasti. Gre za masivne, ponekod
tudi slabo plastnate, praviloma dobro sortirane oosparitne, ooonkosparitne in intrao-
osparitne apnence, ki vsebujejo bolj ali manj številne foraminifere, alge, odlomke
moluskov ter posamične korale in hidrozoje. Večinoma gre za dobro izprane apnence
tipa "grainstone". Slabo izprani oolitni apnenci so redki, pripadajo pa oomikritu in
biomikritu tipa "packstone". V oolitnih apnencih dobimo vložke mikritov, biomikri-
tov, včasih tudi nepravilne leče ali vložke poznodiagenetskega dolomita. V oolitnih
apnencih se pojavljajo vodoravna in navzkrižna laminiranost ter postopna zmavost.
Ponekod so organizmi nakopičeni v toliki množini, da sestavljajo manjše ozke grebe-
ne, ki se bočno izklinjajo. Med grebenotvornimi organizmi so prevladovali hidrozoji,
spongije in korale, na območju grebenov pa so živeli tudi polži (nerineide), školjke,
briozoji, alge in foraminifere. Redki so bili grebeni, ki so jih sestavljali stromatoporo-
idi, korale in hetetide. Opisane grebene uvrščamo med zatišne grebene.
Proti koncu spodnjega malma je morje postajalo vse plitvejše. Med spodnjim in
zgornjim kimmeridgijem je ponekod prišlo celo do lokalnih emerzij. Na nastalem ko-
pnem sta nastajala breča in boksit. Talnino malmskega boksita sestavljajo oolitni
apnenci, ki so na površini precej zakraseli. Malmski boksiti so sivkasto, opekasto,
rjavo in oranžno rdeči, redkeje sivkasto rumeni. Struktura boksitov je pelitna, ooli-
tna in pizolitna. Boksiti se pojavljajo v lečah in tankih plasteh. Debelina boksitnih
teles je nekaj metrov. Ponekod imajo povečano vsebnost kaolinita in jih prištevamo h
glinastim boksitom. V sestavi boksitov se najpogosteje pojavljajo boehmit, kaolinit,
hematit in kremen.
Zgomjemalmsko zaporedje sedimentov sestavljajo algni in foraminifemi apnenci,
dolomiti in njihove breče. Sedimenti, ki smo jih uvrstili v zgomji malm, se odlikujejo
Biostratigrafija plitvovodnih jurskih plasti južnovzhodne Slovenije_20^
z bogato mikrofosilno združbo modro zelenih alg in bentonskih foraminifer, zaradi
česar jih upravičeno imenujemo algni in foraminifemi. Zgornjemalmski sedimenti
južnovzhodne Slovenije so nastajali na obsežni karbonatni platformi v plitvi vodi
podplimskih, medplimskih, nadplimskih in tudi lagunarnih okolij. Prisotnost organ-
ske snovi, s katero so ti sedimenti ponekod impregnirani in jim v večini primerov daje
temno rjavkasto barvo, kaže na občasno redukcijsko okolje. Nadplimski konglomerat
in laminiti z izsušitvenimi razpokami so se oblikovali v medplimskem in nadplim-
skem okolju.
Konkordantno in kontinuirano na opisanem jurskem sedimentnem zaporedju leže
spodnjekredne plasti. Ponekod se med vrhnjimi jurskimi in bazalnimi krednimi pla-
stmi opaža rahla kotna diskordanca, na jurskih kamninah pa počivajo tektonsko in
erozijsko odložene, nekaj sto metrov debele plasti berriasijsko-valanginijsko-haute-
rivijskega konglomerata. V biostratigrafskem pogledu je bila razmejitev obeh siste-
mov postopna. Plasti, ki vsebujejo združbo klipein in tintinin, ter plasti z aberantni-
mi tintininami so še malmske. Navzgor sledijo sedimenti z neznačilno in mešano mi-
krofavno in floro, ki kaže na berriasijsko stopnjo.
Zahvala
Avtorja se zahvaljujeva dr. Dragici Turnšek za determinacijo hidrozojev, spongij,
koral in hetetid ter dr. Raj ki Radoičić za določanje več mikrofosilov in za koristne
nasvete. Za kritično oceno rokopisa, ki je pripomogla k njegovi izboljšavi, se zahva-
ljujeva akad. prof. dr. Mariu Pleničarju in uredniku revije prof. dr. Stanku Buserju.
Nadaljnja zahvala velja prof. dr. Simonu Pircu za pomoč pri prevajanju v angleščino,
sodelavkam Meti Karer, Majdi Saradjen in Marjeti Oman pa za tehnično pripravo
članka.
204_Stevo Dozet & Ljudmila Šribar
References
Bukovac, J., Velie, L & Sokač, B. 1974: Stratigraphie gap Middle Lias-Middle
Malm. Locality Martinšćak (south from Karlovac). Excursion guide book. - The З"' Symposium
of the Yugoslav Sedimentologists, 3-6, Zagreb.
Bukovac, J., Poljak, M., Šušnjar, M. & Čakalo, M. 1984: The explanatoiy
text of the Črnomelj sheet. Basic geologic map of Yugoslavia, 1:100 000.- Federal Geological
Survey, 1-63 pp., Beograd.
B u s e r, S. 1965: Stratigrafski razvoj jurskih skladov na južnem Primorskem, Notranjskem
in zahodni Dolenjski. - Doktorska disertacija, 101 pp. 20 pl., 3 geol. karte. Naravoslovnotehni-
ška fakulteta, Oddelek za geologijo, Aškerčeva 2, Ljubljana.
B u s e r, S. 1974: The explanatory text of the Ribnica map sheet. Basic geologic map of Yu-
goslavia, 1:100 000. - Federal Geological Survey, 1-60 pp., Beograd.
B u s e r, S. 1978: The Jurassic strata of Trnovski gozd, Hrušica and Logaška planota,- Rud.-
Met. Zbornik, 4, 385-406, Ljubljana.
Buser, S, & Debeljak, I. 1994/95: Lower Jurassic beds with bivalves in south Slove-
nia. - Geologija, 37, 38, 23-62, Ljubljana.
Catenacci, E., De Castro, P. & Sgrosso, I. 1963: Complesse-guida del Mesozoi-
co calcareo-dolomitico nella zona orientale del massiccio del Mátese. - Mem. Soc. Geol. Ital., 4,
1-20, Bologna.
Crescenti, U. 1966: Osservazioni sulla stratigrafia dell'Appennino meridionale alla luce
delle recenti ricerche micropaleontologiche. - Boi. Soc. Geol. Ital., 4, 541-579, Roma.
Crescenti, U. 1969: Biostratigrafia delle facies mesozoiche dell'Appennino centrale:
correlazioni. - Geol. Romana, 8, 15-40, Roma.
Crescenti, U. & Sartoni, S. 1964: Sintesi biostratigrafica del Mesozoico dell'Italia
meridionale. - Mem. Soc. Geol. Ital., 4, 2, 685-692, Bologna.
De Castro, E 1962: II Giura-Lias dei Monti Lattari e dei rilievi ad ovest della Valle
del,Imo e della Piana di Montoro. - Boll. Soc. Natur., 71, 3-34, Napoli.
De Castro, P. 1963: Sulla presenza del Giura (Dogger e Malm) nei Monti Aurunei.- Boll.
Soc. Natur, 71, 16-19, Napoli.
Dozet, S. 1989: Tectonic movements in the Younger Paleozoic and Mesozoic in the Kočev-
je area (Southern Slovenia). - Rud.-Met. Zbornik, 36/4, 663-673, Ljubljana.
Dozet, S. 1990: Biostratigraphic subdivision of the Jurassic and Lower Cretaceous beds in
Kočevje and Gorski Kotar area. - Rud.-Met. Zbornik, 33/1, 3-18, Ljubljana.
Dozet, S. 1993: Lofer cyclothems from the Lower Liassic Krka Limestones. - Riv. It. Pale-
ont. Strat., 99, 1, 88-100, Milano.
Dozet, S. 1994: Stratigraphy of the Suha Krajina area (Slovenia) and stratigraphie gap
Middle Liassic-Lower Malm. - Rud.-Met. Zbomik, 41, 231-238, Ljubljana.
Dozet, S. 1996: Foraminiferal and algal biostratigraphy of the Jurassic beds in southeast-
em Slovenia. - Rud.-Met. Zbomik, 43/1-2, 3-10, Ljubljana.
Dozet, S. & Šribar, L. 1981: Biostratigraphy of Jurassic beds south of Prezid in Gors-
ki Kotar area. - Geol.-Razpr. Por, 24, 1, 109-126, Ljubljana.
Farinacci, A. & Radoičić, R. 1964: Correlazione fra serie giuresi e cretacee
dell'Appennino centrale e delle Dinaridi esterne. - Ric. sci., 34, 2a, 269-300, Roma.
Fisher, A. G. 1964: The Lofer cyclothems of the Alpine Triassic. Symposium on cyclic
sedimentation. In: M e r r i a m D. F (Ed). - Kansas Geol. Surv., BuU., 169, 107-149, Lawrence.
Folk, R. L. 1959: Practical pétrographie classification of limestones. - Am. Assoc. Petrol.
Geol. Bull., 43, 1, 1-38, Tulsa.
Gušić, I. 1969: Biostratigraphic and micropaleontologic characteristics of some Jurassic
cross-sections in central Croatia. - Geol. Vjes., 22, 89-97, Zagreb.
Gušić, I., Nikler, L. & Sokač, B. 1971: The Jurassic in the Dinaric mountains of
Croatia and the problems of its subdivision. - Ann. Inst. Geol. Pubi. Hung., 54/2, 165-183,
Budapest.
Nikler, L. & Sokač, B. 1968: Biostratigraphy of the Jurassic of Velebit. - Geol. Vjesn.,
21, 161-176, Zagreb.
Pleničar, M. 1970: The explanatory text of the Postojna map sheet. Basic geologic map
of Yugoslavia, 1:100 000. - Federal Geological Survey, 1-62 pp., Beograd.
Pleničar, M. & Premru, U. 1977: The explanatory text of the Novo mesto map sheet.
Basic geologic map of Yugoslavia, 1:100 000. - Federal Geological Survey, 61 pp., Beograd.
Radoičić, R. 1964: Micropaleontologic characteristics and stratigraphie correlation of
some Jurassic columns in Outer Dinarides. - Nafta, 10, 293-303, Zagreb.
Radoičić, R. 1966: Microfaciès du Jurassique des Dinarides extemes de la Yougoslavie. -
Geologija, 9, 5-378, Ljubljana.
Biostratigraphy of Shallow Marine Jurassic Beds in Southeastern Slovenia_205
Radoičić, R. 1969: La branche aberrante des Tintinnines fossiles. (Sous-Ordre Tintinnina).
- Palaeont. Jugoslavica, SAZU, 9, 5-71, Zagreb.
Radoičić, R. 1987: Spiraloconulus perconigi Allemann & Schroeder (Foraminifera) in
some Jurassic series of Yugoslavia, Greece and Iraq. - Geol. glas., 12, 117-139, Titograd.
Sartoni, S. & Crescenti, U. 1959: La zona a Palaeodasycladus mediterraneus (Pia)
nel Lias dell'Appennino meridionale. - Giom. Geol. Ann. Museo Geol., 2, 27, 115-139, Bologna.
Sartoni, S. & Crescenti, U. 1962: Ricerche biostratigrafiche nel Mesozoico dell'Ap-
pennino meridionale. - Giom. Geol. Ann. Museo Geol., 2a, 29, 161-304, Bologna.
Savić, D. & Dozet, S. 1985: The explanatory text of the Delnice map sheet. Basic geo-
logie map of Yugoslavia, 1:100 000. - Federal Geological Survey, 66 pp., Beograd.
Strohmenger, C. & Dozet, S. 1991: Stratigraphy and geochemistry of Jurassic car-
bonate rocks from Suha Krajina and Mala gora mountain (Southern Slovenia). - Geologija, 33,
315-351, Ljubljana.
Š p a r i c a, M. 1981: The Mesozoic of the Banija, Kordun and Bosnia area. -Nafta, 2-5, Za-
greb.
Tollmann, A. 1966: Die alpidischen Gebirgsbildungs-Phasen in den Ostalpen und West-
karpaten. - Geotektonische Forschungen, 21, 1-156, Stuttgart.
T u r n š e k, D. 1966: Upper Jurassic hydrozoan fauna from southern Slovenia. - Razpr. Prir.
Med. Ved., Cl. 4, 9, 8, 337-428, Ljubljana.
T u r n š e k, D. 1969: A contribution to the paleoecology of Jurassic hydrozoa from Slove-
nia. - Razpr. Prir Med. Ved., Cl. 4, 12, 5, 211-237, Ljubljana.
T u r n š e k, D. 1972: Upper Jurassic corals of southern Slovenia. - Razpr. Prir. Med. Ved.,
Cl. 4, 15, 6, 147-265, Ljubljana.
T u r n š e k, D., B u s e r, S. & O g o r e 1 e c, B. 1981: An Upper Jurassic reef complex
from Slovenia, Yugoslavia. - SEPM. spec, pubi., 30, 361-369, Tulsa.
V e 1 i Ć, I. 1977: Jurassic and Lower Cretaceous assemblage-zones in Mt. Velika Kapela,
Central Croatia. - Prir. Istr. Acta Geol., 9, 2, 42, 15-37, Zagreb.
206_Stevo Dozet & Ljudmila Šribar
Plate 1 - Tabla 1
1	Biooosparitic limestone with fragments of gastropods and pelecypods (8 x)
Cross-section Krka-Hočevje, Lower Liassic
Biooosparitni apnenec z ostanki polžev in školjk (8 x)
Profil Krka-Hočevje, spodnji lias
2	Biopelmicrosparitic limestone with remains of alga Palaeodasycladus mediterraneus (Pia),
30 X, Mala gora - Middle Liassic
Biopelmikrosparitni apnenec z ostanki alg Palaeodasycladus mediterraneus (Pia), 30 x
Mala gora - srednji lias
3	Pelintrasparitic limestone with Orbitopsella praecursor (Guembel), 35 x
Trnovski gozd. Middle Liassic
Pelintrasparitni apnenec z algo Orbitopsella praecursor (Guembel), 35 x
Trnovski gozd, srednji lias
Biostratigraphy of Shallow Marine Jurassic Beds in Southeastern Slovenia
207
208_Stevo Dozet & Ljudmila Šribar
Plate 2 - Tabla 2
1	Pelmicrosparitic limestone w^ith Orbitopsella praecursor (Guembel), 34 x
Dolenja Ponikva, Middle Liassic
Pelmikrosparitni apnenec z Orbitopsella praecursor (Guembel), 34 x
Dolenja Ponikva, srednji lias
2	Oosparitic limestone with foraminifer Protopeneroplis striata Weynschenk (84 x)
Cross section Krka-Hočevje, Dogger-Malm
Oosparitni apnenec s foraminifero Protopeneroplis striata Weynschenk (84 x)
Profil Krka-Hočevje, dogger-malm
3	Dismicrosparitic limestone with foraminifer Protopeneroplis striata Weynschenk (70 x)
W of Komama vas
Upper Dogger-Lower Malm
Dismikrosparitni apnenec s foraminifero Protopeneroplis striata Weynschenk (70 x)
W od Komame vasi
Zgornji dogger-spodnji malm
4	Pfenderina salernitana Sartoni & Crescenti (34 x)
W of Komama vas
Upper Dogger-Lower Malm
Pfenderina salernitana Sartoni & Crescenti (34 x)
W od Komame vasi
Zgomji dogger-spodnji malm
Biostratigraphy of Shallow Marine Jurassic Beds in Southeastern Slovenia
209
210_Stevo Dozet & Ljudmila Šribar
Plate 3 - Tabla 3
1, 2 Microsparitic limestone with alga Salpingoporella sellii (Crescenti), 42 x
NE of Milanov vrh, Lower Malm
Mikrosparitni apnenec z algo Salpingoporella sellii (Crescenti), 42 x
NE od Milanovega vrha, spodnji malm
3, 4 Biointrasparitic limestone with trocholinids, pfenderinas and verneuilinidas (42 x)
N of Ajbik, Lower Malm
Biointrasparitni apnenec s trocholinami, pfenderinami in verneuilinidami (42 x)
N od Ajbika, spodnji malm
Biostratigraphy of Shallow Marine Jurassic Beds in Southeastern Slovenia
211
212_Stevo Dozet & Ljudmila Šribar
Plate 4 - Tabla 4
1	Cladocoropsis mirabilis Felix (8 x)
Transverse section of coenosteum, section Krka-Hočevje, Lower Malm
Cladocoropsis mirabilis Felix (8 x)
Prečni presek cenosteja, profil Krka-Hočevje, spodnji malm
2	Cladocoropsis mirabilis Felix (8 x)
Longitudinal section, section Krka-Hočevje, Lower Malm
Cladocoropsis mirabilis Felix (8 x)
Vzdolžni presek, profil Кхка-Hočevje, spodnji malm
3	Biooosparitic limestone, Trocholina alpina (Leupold), 16 x
Črnomelj, Lower Malm
Biooosparitni apnenec, Trocholina alpina (Leupold), 16 x
Črnomelj, spodnji malm
4	Biooosparitic limestone, Trocholina alpina (Leupold), 50 x
Črnomelj, Lower Malm
Biooosparitni apnenec, Trocholina alpina (Leupold), 50 x
Črnomelj, spodnji malm
Biostratigraphy of Shallow Marine Jurassic Beds in Southeastern Slovenia
213
214_Stevo Dozet & Ljudmila Šribar
Plate 5 - Tabla 5
1	Biopelmicrosparitic limestone with alga Clypeina jurassica Favre (18 x)
N of Ajbik, Upper Malm
Biopelmikrosparitni apnenec z algo Clypeina jurassica Favre (18 x)
N od Ajbika, zgornji malm
2	Algal biolithite, Clypeina jurassica Favre (8 x)
N of Ajbik, Upper Malm
Algni biolitit, Clypeina jurassica Favre (8 x)
N od Ajbika, zgornji malm
3	Biopelmicrosparitic limestone with alga Clypeina jurassica Favre (18 x)
N of Ajbik, Upper Malm
Biopelmikrosparitni apnenec z algo Clypeina jurassica Favre (18 x)
N od Ajbika, zgomji malm
4	Biopelmicrosparitic limestone with alga Clypeina jurassica Favre (18 x)
Čabranska polica, Upper Malm
Biopelmikrosparitni apnenec z algo Clypeina jurassica Favre (18 x)
Čabranska polica, zgomji malm
Biostratigraphy of Shallow Marine Jurassic Beds in Southeastern Slovenia
215
216_Stevo Dozet & Ljudmila Šribar
Plate 6 - Tabla 6
1	Biopelsparitic limestone with alga Clypeina jurassica Favre and aberrant tintinnids
(34 x), NW of Vid, Upper Malm
Biopelsparitni apnenec z algo Clypeina jurassica Favre in aberantnimi tintininami
(34 x), NW od Vida, zgomji malm
2	Biointrasparitic limestone with alga Clypeina jurassica Favre and aberrant tintinnids
(34 x), Škrempljevec, Upper Malm
Biointrasparitni apnenec z algo Clypeina jurassica Favre in aberantnimi tintininami
(34 x), Škrempljevec, zgomji malm
3	Biointrasparitic limestone with alga Clypeina jurassica Favre and aberrant tintinnids
(34 X), NW of Vid, Upper Malm
Biointrasparitni apnenec z algo Clypeina jurassica Favre in aberantnimi tintininami
(34 x), NW od Vida, zgomji malm
4	Detritic biolithitic limestone, Clypeina jurassica Favre, Solenopora sp.,
Tintinnopsella sp., (30 x)
Kmica, Upper Malm
Detritični biolititni apnenec, Clypeina jurassica Favre, Solenopora sp.,
Tintinnopsella sp., (30 x),
Kmica, zgomji malm
Biostratigraphy of Shallow Marine Jurassic Beds in Southeastern Slovenia
217
218_Stevo Dozet & Ljudmila Šribar
Plate 7 - Tabla 7
1	Clypeina jurassica Favre (34 x)
E of Vid, Upper Malm
Clypeina jurassica Favre (34 x)
E od Vida, zgomji malm
2	Aberrant tintinnids (34 x)
Jurna vas. Upper Malm
Aberantne tintinine (34 x)
Juma vas, zgomji malm
3	Piannella cf. gigantea Carozzi (34 x)
W of V. Slatnek, Upper Malm
Piannella cf. gigantea Carozzi (34 x)
W od V. Slatneka, zgomji malm
4	Biopelsparitic limestone with Pseudocyclammina lituus (Yokoyama), 34 x
Ušivec-Birčna vas, Upper Malm
Biopelsparitni apnenec s Pseudocyclammina lituus (Yokoyama), 34 x
Ušivec-Birčna vas, zgomji malm
Biostratigraphy of Shallow Marine Jurassic Beds in Southeastern Slovenia
219
220_Stevo Dozet & Ljudmila Šribar
Plate 8 - Tabla 8
1	Biomicritic limestone, Tintinnopsella sp., aberrant tintinnids (34 x)
W od Jablanica, Upper Malm
Biomikritni apnenec, Tintinnopsella sp., aberantne tintinine (34 x)
W od Jablanice, zgomji malm
2	Biomicritic limestone, Cambelliella milesi Radoičić (34 x)
Petekovec, Upper Malm
Biomikritni apnenec, Cambelliella milesi Radoičić (34 x)
Petekovec, zgornji malm
3	Biomicritic limestone, aberrant tintinnids and Salpingoporella annulata Carozzi (34 x)
NE of Zabiče, Upper Malm
Biomikritni apnenec, aberantne tintinine in Salpingoporella annulata Carozzi (34 x)
NE od Zabič, zgomji malm
4	Pelmicrosparitic limestone, Tintinnopsella sp. (34 x)
Čabranska polica. Upper Malm
Pelmikrosparitni apnenec, Tintinnopsella sp. (34 x)
Čabranska polica, zgomji malm
Biostratigraphy of Shallow Marine Jurassic Beds in Southeastern Slovenia
221