GEOLOGICA CARPATHICA, 53, 1, BRATISLAVA, FEBRUARY 2002
53 — 59
GEOLOGY OF THE VARDAR ZONE OPHIOLITES OF THE
MEDVEDNICA MOUNTAIN AREA LOCATED ALONG THE
ZAGREB-ZEMPLIN LINE (NW CROATIA)
DAMIR SLOVENEC
1
and JAKOB PAMIĆ
2
1
Institute of Geology, Sachsova 2, HR-10 000 Zagreb, Croatia
2
Croatian Academy of Science and Art, Ante Kovačića 5, HR-10 000 Zagreb, Croatia
(Manuscript received March 6, 2001; accepted in revised form October 4, 2001)
Abstract: The ophiolite mélange of the Medvednica Mountain area, located in the southwestern parts of the Zagorje-
Mid-Transdanubian or Sava Zone, is included within the Vardar Zone (VZ) of the Dinarides. The mélange represents the
northwesternmost parts of the Dinaridic ophiolites, the origin of which was related to the Alpine evolution of the Dinaridic
part of the Tethys. The Dinaridic ophiolites represent fragments of Mesozoic oceanic crust generated over 150 Ma
starting with a) Late Triassic (?) to Late Jurassic oceanization of the Tethys, Late Jurassic/Early Cretaceous subduction,
obduction and formation of the Dinaride Ophiolite Zone (DOZ) to b) Cretaceous—Early Paleogene back-arc basin final
subduction and obduction, that is the formation of the VZ. The main Alpine compressional-collisional event, which took
place in the Eocene (55—45 Ma) gave rise to the final structuration of the Dinarides and their uplift, and backthrusting of
the VZ onto the DOZ. The Medvednica ophiolite mélange represents a chaotic complex in which primary sedimentary
sequences are rarely preserved due to subsequent tectonism. The mélange is characterized by pervasively sheared and
fine-grained shaly-silty matrix in which are included smaller (centimetre to hektometre) and larger (kilometre) frag-
ments of various rocks. These are most commonly greywackes, ophiolites, cherts and exotic limestones, the youngest
blocks of which are Late Cretaceous and Paleocene in age. For that reason the VZ ophiolite mélange is of post-Paleocene
age as distinguished from the Jurassic ophiolite mélange of the DOZ. The Medvednica ophiolites are represented by
tectonic and cumulate serpentinized peridotites, gabbro-diabases and basalts, transformed by postmagmatic processes,
into serpentinites, metagabbros, metadiabases and metabasalts. The Medvednica ophiolites can be correlated to the
ophiolites from the northwestern part of the Zagorje-Mid-Transdanubian (or Sava) Zone and the Bükk area in northern
Hungary. The present position of all these ophiolites can be best explained by the mechanism of extrusion tectonics, for
example strike slip faulting as a result of Oligocene and Neogene indenting of Apulia into Eurasia.
Key words: Late Cretaceous—Paleogene, Medvednica Mt, Zagorje-Mid-Transdanubian (Sava) Zone, Vardar Zone, ophiolite
mélange, subduction, obduction, extrusion tectonics.
Introduction
The Dinarides, which can be traced along strike for about 700
km, represent a complex fold, thrust and imbricate belt which
developed along the northeastern margin of the Adriatic mi-
croplate or Apulia (Dewey et al. 1973). Spatially, the Dinar-
ides are not precisely defined but, generally, it is believed that
they merge in the southeast with the Hellenides and in the
northwest with the Alps. In the north, the Dinarides are bound-
ed by the Pannonian Basin, that is, the Tisia (Fig. 1).
The Dinaridic ophiolites and genetically related sedimentary
formations have fixed geotectonic position by their occurrence
in the Dinaride Ophiolite Zone (DOZ) and Vardar Zone (VZ).
Kossmat (1924) first defined the VZ, restricting its occurrence
to southern Serbia, Macedonia and northern Greece; this is the
VZ sensu stricto. Afterwards it was recognized that the zone
continues further northward and northwestward (Aubouin
1974) into the area south of the Sava River up to the Zagorje-
Mid-Transdanubian (or Sava) Zone. This extended zone is the
VZ sensu lato, although the more adequate term would be the
Sava-Vardar Zone (Pamić 2001).
Genetically, the ophiolites from the DOZ were probably re-
lated to the Tethyan open ocean realm, whereas the ophiolites
from the VZ were related to the North Tethyan active conti-
nental margin, that is, the back-arc basin. Due to these differ-
ent settings, ophiolites from the two zones have their peculari-
ties regarding their ages, relations with genetically related sed-
imentary formations and some other aspects (Pamić et al.
2001).
The northwesternmost outcrops of the Dinaridic ophiolites
occur in the Medvednica Mt and the adjacent Ivanščica and
Kalnik Mts (Pamić 1997) located in the Zagorje-Mid-Trans-
danubian (or Sava) Zone (Pamić & Tomljenović 1998). Nu-
merous papers have been published on these ophiolites and
they have been summarized elsewhere (Crnković 1963; Šikić
1995a,b; Tomljenović 1995; Pamić 1997; Halamić 1998; Slov-
enec 1998).
The aim of this paper is to present geological data on ophio-
lites from the Medvednica Mt and adjacent mountains and
give correlation with the ophiolites from the surrounding parts
of the Dinarides and Zagorje-Mid-Transdanubian (or Sava)
Zone in Hungary.
Geotectonic position
The Medvednica Mt is included in the southwestern part of
the Mid-Transdanubian Zone (Fülöp & Dank 1978) recently
54 SLOVENEC
and PAMIĆ
renamed the Zagorje-Mid-Transdanubian Zone – ZMTZ
(Pamić & Tomljenović 1998) and the Sava Zone, respectively
(Haas et al. 2000). In northwestern Croatia, the ZMTZ can be
traced along strike for about 120 km, stretching in a NE-SW
direction which is nearly perpendicular to the NW-SE strike of
the Dinaridic structures (Fig. 1). With its southwesternmost
boundary the ZMTZ is thrust onto the northeastern margin of
the External Dinarides (Mesozoic carbonate platform), where-
as westwards the zone continues in the system of the Sava and
Julian-Savinja nappes (Mioč 1984; Pamić 1993; Haas et al.
2000). In the east the zone is bounded by the Zagreb-Zemplin
Line (Grecula & Varga 1979). In some geotectonic schemes
the ZMTZ continues for about 400 km in the northeastern di-
rection as the Igal and Bükk Unit (Árkai et al. 1991).
The ZMTZ is characterized by mixed Alpine-Dinaridic tec-
tonostratigraphic units (Pamić & Tomljenović 1998; Haas et
al. 2000). This is best exemplified by the Medvednica Mt
which can be traced along a NE strike for about 40 km. The
mountain is composed of numerous Paleozoic, Mesozoic-Pa-
leogene and Neogene formations (Šikić et al. 1995a,b) which
can be grouped into four main tectonostratigraphic units (Fig.
2). The present-day thrust succession from the bottom to the
top is as follows: (1) Tectonized ophiolite mélange; (2) Paleo-
zoic-Triassic metamorphic complex overprinted by Early Cre-
taceous metamorphism; (3) Late Cretaceous-Paleocene flysch,
and (4) Triassic sequences mainly of carbonate platform facies
(Pamić & Tomljenović 1998).
The relationship of these units with the basement is ambigu-
ous. In the northeastern part of the Medvednica Mt, Triassic
clastics and carbonates crop out in a way suggesting that they
might have been originally the basement of the ophiolite mé-
lange. A similar ambiguous structural relationship is known
between the ophiolite-bearing and underlying units composed
of Late Paleozoic and Triassic clastics, carbonates and volca-
nics in adjacent Ivanščica Mt (Šimunić et al. 1982).
Basic geological data
The ophiolite mélange of the Medvednica Mt is a chaotic
lithological unit in which primary depositional sequences are
rarely preserved due to subsequent tectonic activity. The ophi-
olite mélange is characterized by pervasively sheared and fine-
grained shaly-silty matrix in which fragments of various rocks
are included (Fig. 3). The size of the fragments varies from
small (centimetre—decimetre—metre—hektometre) to large (ki-
lometre) mappable dimensions.
The most common fragments embedded in the matrix are
greywackes and arenites in the form of flow-balls, 4—150 cm,
locally up to 10 m in diametre, and slumps. These formations
originated by tectonic deformation which finally resulted in
the formation of chaotic fabric, for example “block-in-matrix
texture” (Raymond 1984). Originally interlayered sediments
are mutually mixed and included into sheared silty-pelitic ma-
trix and thus correspond to “autoclastic rocks”. According to
Raymond (1984) this is a broken formation (beta-unit which
has signatures of the stratigraphic unit) and locally incoherent
complex (gamma-unit – without signatures of the strati-
graphic unit). Undisturbed sequences with alternating
graywackes and shales are very rarely preserved. The shale is
mainly composed of quartz and a mixture of illite and highly
illitic interlayered illite-smectite and, to a lesser extent, of
chlorite and some plagioclase. In some places, shales are
strongly silicified. Greywackes are composed of quartz (23—54
%), feldspars (11—25 %), and biotite, muscovite and chlorite
(1—12 %); the most common rock fragments are quartzites,
cherts, volcanics and pyroclastics.
The shaly-silty matrix also includes fragments of ophiolites.
Incorporation of solid and detached blocks of igneous and sed-
imentary rocks can probably be explained, at least partly, by
the olistostrome mechanism. This took place on the trough
slope and was subsequently stimulated by subduction process-
es in the growing zone of the accretion prism. The only excep-
tion is a large volcanic body (10 km
2
), about 400 m thick,
which is interlayered with sediments and pyroclastics (volca-
nic breccias and lapilli tuffs). All these data point to polyphase
submarine and synsedimentary volcanic activity. Sediments
included in the volcanics are represented by fragments of
greywacke, arenite, and chert, 3—40 cm in diametre, mixed
with sandy mudstone and lithic greywacke with 35 % illite, 33
% quartz, “amorphous matter” and chlorite. In a smaller basal-
tic body in the Orešje Quarry in Bistra Valley, pillow lavas in-
clude xenoliths of Middle Triassic limestones (Halamić et al.
1998; Fig. 3).
Besides the fragments mentioned above, the ophiolite mé-
lange also contains large, frequently mappable fragments com-
Fig. 1. Major paleogeographical and structural units of the Dinar-
ides (simplified after Aubouin 1974).
GEOLOGY OF THE VARDAR ZONE OPHIOLITES OF MEDVEDNICA 55
posed of greyish and reddish cherts, shales, siltites and micrites
interlayered with volcanics. In chert fragments from the area
between the Bistra and Poljanica Creeks, Ladinian-Norian ra-
diolarians were determined (Fig. 3; Halamić 1998). In the
same area Middle and Upper Jurassic fossiliferous radiolarites
occur, in which Middle to Upper Triassic carbonate olistoliths,
metres in diameter are included (Halamić et al. 1999). In the
area of Drenovec Creek greyish platy micrites with chert lens-
es and interlayers crop out.
The Medvednica ophiolite mélange also includes exotic me-
tre—hektometre and kilometre mappable fragments composed
of limestone, calcarenite grading into siltite, calcareous sand-
stone, sandstone and shale succession of Albian—Cenomanian
age (Gušić 1971, 1974). The fragments themselves do not in-
clude any ophiolite. These formations were fragmented and
transported along parallel thrust faults during the generation of
the olistostrome mélange, and as exotic blocks were incorpo-
rated, partly gravitationally, into the frontal parts of the accre-
tionary prism in the chaotic matrix of the subducted complex.
For that reason such a structural complex corresponds to the
tectonic ophiolite mélange (delta-unit) as proposed by Ray-
mond (1984) or to an olistostrome deformed within the shear
zone of the accretionary prism, that is the increasing zone of
the subducted complex (Orange & Underwood 1995). Large
exotic blocks, decimetre—metre—hektometre in size, also oc-
cur. They are composed of Rhaetian-Liassic limestones and
dolomitic limestones. The blocks were subsequently cement-
ed by fossiliferous pelmicrite and clay of Senonian age form-
ing polymicte breccias (Babić et al. 1973). Contact between
syngenetic and exotic fragments is mainly disconformable
(tectonic) in character. Triassic-Jurassic carbonate formations,
together with parts of rocks incorporated in the subduction
complex (sandstones, cherts and orbitolina limestones) were
redeposited during Late Jurassic/Early Cretaceous tectonic
processes by submarine sliding mechanism from the marginal
parts into the basin characterized by pelagic sedimentation.
Afterwards they were incorporated, together with Senonian
breccias, into the ophiolite mélange. The fact that the Senon-
ian breccias are the youngest fragments (“olistoliths”) includ-
ed in the Medvednica ophiolite mélange indicates its post-Se-
nonian, e.g. Paleogene age. In the adjacent Kalnik Mt the
youngest exotic limestone fragments included in the ophiolite
mélange are of Paleocene age (Šimunić & Šimunić 1992).
The Medvednica ophiolite mélange is thrust by Late Creta-
ceous/Paleocene flysch composed of conglomerates, sand-
stones, thin-bedded siltites and laminated shales grading into
Fig. 2. Simplified geological map of the Medvednica Mt with the main tectonostratigraphic units (Pamić & Tomljenović 1998).
56 SLOVENEC
and PAMIĆ
hemipelagic Scaglia-type micrites originating in a trench of
the back-arc basin (Tomljenović 1995). By contrast, the ophio-
lite mélange of the DOZ is disconformably overlain by Late
Jurassic/Early Cretaceous Urgon-type (?) clastic and subordi-
nate carbonate formations, for example the Pogari Series (Jo-
vanović 1957; Pamić et al. 2001).
Age of mélange and ophiolites
The precise age of ophiolite mélange cannot be determined
due to its chaotic nature and large stratigraphic span of the ex-
otic limestone blocks included in it. The youngest limestone
blocks are of Late Cretaceous age, in the adjacent Kalnik Mt
even of Paleocene age (Šimunić & Šimunić 1992), indicating
that the ophiolite mélange as a whole is of Paleocene or post-
Paleocene age (Pamić 1997). Consequently, the Medvednica
ophiolite mélange and the mélange of the entire VZ is distinct-
ly different from the DOZ ophiolite mélange in which the
youngest exotic limestone blocks are Tithonian indicating
post-Tithonian age of the mélange (Pamić et al. 2001).
In the shaly-silty matrix of the Medvednica ophiolite mé-
lange, as well as in the rarely preserved profiles with alternat-
ing shales and greywackes to date no characteristic fossils
were found. Only on one outcrop on the greywacke bedding
surface well preserved angiosperm leaves were found, sug-
gesting that they are not older than Early Cretaceous (Koch,
pers. comm.).
This conclusion is compatible with the K-Ar ages of 94.3
and 85.4 Ma (Turonian—Senonian) which were obtained on
two fresh basalt samples taken from the largest volcanic body
in the Medvednica Mt. On a fresh basalt sample interlayered
with Cretaceous sediments from the adjacent Kalnik Mt K-Ar
ages of 86.8 Ma were measured. These radiometric ages can
be correlated with those ranging from 109.6 to 62 Ma (Albian—
Cenomanian) which were obtained on gabbro and diabase
samples taken in several deep oil-wells in the neighbouring
Sava Depression (Pamić 1997).
In this respect the ophiolites of the Medvednica Mt and the
whole VZ differ from the ages of ophiolites from the DOZ
ranging most commonly between 174±14 and 136±15 Ma
(Pamić et al. 2001). However, in the adjacent Kalnik Mt K-
Ar ages of 189—185 Ma (Lias) were measured on two frag-
ments of dolerite-gabbros included in the ophiolite mélange.
This indicates that in some places the ophiolite mélange of
the northwesternmost parts of the VZ Jurasic ophiolite frag-
ments are also preserved. The ophiolite mélange of the
Medvednica and Kalnik Mts also include fragments of Ani-
sian-Carnian non-ophiolite related tholeiitic basalts interlay-
ered with penecontemporaneous sediments (Halamić &
Goričan 1995; Halamić et al. 1998). Hence, besides pre-
served fragments of Jurassic ophiolites, the ophiolite mé-
lange of the ZMTZ includes fragments of Triassic, probably
rift-related, volcanics.
Two groups of K-Ar ages were also obtained for the Darnó-
Hill ophiolites from the northeasternmost parts of the ZMTZ
in Hungary. The first group includes K-Ar ages of 175—152
Ma obtained on gabbros and in the second one K-Ar ages of
110—100 Ma measured on basalts (Árva-Sós & Józsa 1992).
The ophiolites are associated with radiolarites of Ladinian—
Carnian and Bajocian—Callovian ages (Dosztály & Józsa
1992; Dosztály 1994).
Basic petrological data
The ophiolite rocks of the Medvednica Mt are not different
from the ophiolites of the whole Alpine-Himalayan belt, for
Fig. 3. Simplified geological map of the part of the Medvednica Mt composed mainly of tectonized ophiolite mélange (modified after
Halamić 1998).
GEOLOGY OF THE VARDAR ZONE OPHIOLITES OF MEDVEDNICA 57
example they include Alpine-type peridotites, gabbros and di-
abase-basalts.
Ultramafic rocks are represented by tectonic and cumu-
late peridotites (Šimunić & Pamić 1989; Slovenec 1998).
The peridotite tectonites are characterized by metamorphic
fabric, for example porphyroblastic texture, massive and
parallel structure shown in foliation. They are represented
most commonly by harzburgite composed of recrystallized
enstatite porphyroblasts (Fs
10
) embedded into a matrix of
serpentinized olivine (Fo
90
). The harzburgites are most
commonly completely serpentinized. Cumulate peridotites
are represented by amphibole- and plagioclase-bearing
harzburgite, cortlandite, plagioclase-hornblende lherzolite
and quite subordinate hornblende websterite. All these
rocks have magmatic fabric; their major minerals are oliv-
ine (Fo
81.5—80.1
), diopside, bronzite, amphibole (both prima-
ry edenite-pargasite and secondary uralite), and calcic pla-
gioclase, commonly completely altered into hydrogarnet
(Crnković 1963; Slovenec 1998).
Mafic intrusive rocks are represented by amphibole
gabbro, uralitized metagabbro, scarce olivine metagabbro,
leucocratic metagabbro, and gabbro-diabase/metagabbro-
metadiabase. These rocks are medium- to coarse-grained,
partly poikilitic, and massive in structure. The major miner-
als are plagioclase (commonly bytownite), clinopyroxene
(augite-diopside), amphibole (hornblende and uralite) and
olivine, all of them accompained by secondary minerals.
Mafic vein rocks occur in the form of chilled dykes, me-
tre to decametre thick, within the main Medvednica volca-
nic body (Fig. 3). They are represented commonly by al-
tered diabase-dolerites. These rocks have the same mineral
and chemical composition as the associated volcanic rocks.
Within gabbro blocks incorporated in the mélange, rare
decimetre-thick veins of gabbro-aplite and gabbro-pegma-
tite occur.
Mafic extrusive rocks build up the Medvednica main
volcanic body and occur as metre—hektometre fragments in
the ophiolite mélange (Fig. 3). The main volcanic body is
the product of polyphase volcanic activity as indicated by
multiple occurrence of pillow lavas interlayered with sedi-
ments. These rocks are represented by fresh basalts and
more commonly by metabasalts and spilites.
Plagioclases (andesine, labradorite) occur as phenocrysts
in fresh basalts and diabases and more commonly in
groundmass. Albite (An
3—5
), which originated by albitiza-
tion of primary calcic plagioclase, is a major mineral in
more common metabasalts and metadiabases. Clinopyrox-
ene (augite, titanoaugite) is frequently transformed into
chlorite and cryptocrystalline mixture of clinocoizite, epi-
dote and leucoxene. Volcanic rocks are cross-cut by vein-
lets and lenses and permeated by amygdules filled by chlo-
rite, epidote, coizite, prehnite and zeolite (natrolite?).
Pumpellyite and volcanic glass build up the peripheral parts
of pillows, 0.5—1.0 cm thick; they probably represent the
product of devitrification which took place during the hy-
drothermal activity. The accessory minerals are ilmenite,
sphene, anatase, rutile, leucoxene, magnetite, chromite (?),
pyrite, and apatite (Slovenec 1998).
Discussion and conclusion
The ophiolite complex of the Medvednica Mt and the sur-
rounding Kalnik and Ivanščica Mts has a prominant Dinaridic
affinity and thus distinctly differs from the Penninic ophiolite
complex from the adjacent Alps. Outcrops of ophiolites posi-
tioned along the Zagreb-Zemplin fault system and within the
ZMTZ, represent the last northwesternmost parts of the Dinar-
idic ophiolites (Pamić 1997).
According to the model proposed by Pamić et al. (1998a)
and Pamić et al. (2001), the origin of the Dinaridic ophiolites
was related to the geodynamic evolution of the Dinaridic parts
of the Tethys. Generation of the Mesozoic oceanic crust was
taking place from the Late Triassic (?) to Late Jurassic over the
period of 60—70 Ma of oceanization of the Tethys. Along its
northern margin started by the end of Jurassic processes of
north-dipping subduction, e.g. “suprasubduction” (Pearce et
al. 1984) which were accompained by penecontemporaneous
south-verging obduction and dismembering of the oceanic
crust. This was incipient Late Jurassic generation of the DOZ
(Pamić et al. 2001).
The obducted and tectonically dismembered ophiolite com-
plex of the DOZ was partially uplifted and affected by weath-
ering and erosion and detritus of ophiolites and genetically re-
lated sediments redeposited during the Early and Late
Cretaceous in the surrounding marine shoals and depressions.
And thus the ophiolite complex was disconformably overlain
by Cretaceous clastic and carbonate sequences of the Urgon-
ian-type (?) Pogari Series (Jovanović 1957).
Late Jurassic (Tithonian—Berriasian) oceanic subduction ini-
tiated gradual narrowing and closure of the Dinaridic Tethys.
Along its northern margin a magmatic arc was generated, in
the back-arc basin (BARB) where deposition of clastic and
carbonate flysch succession occurred during the Cretaceous
and Early Paleogene (Jelaska 1978). In the BARB environ-
ments persisting subduction made possible continuous genera-
tion of oceanic crust. This is documented by radiometric ages
of 110—62 Ma obtained on mafic ophiolite fragments included
in the VZ ophiolite mélange (Pamić et al. 2001).
Subduction processes terminated during the Eocene (50—45
Ma) when the main Alpine compression-collision took place.
These processes gave rise to final structuring of the Dinarides
and their uplift. The ophiolite mélange originating during the
first Tithonian-Berriasian oceanic obduction was recycled and
the recycled mélange incorporated ophiolite fragments, gener-
ated during the Cretaceous—Early Paleogene, together with ex-
otic fragments of Upper Cretaceous and Paleocene limestones.
Consequently, the second Paleogene obduction of the oceanic
crust gave rise to the second emplacement of ophiolites and
genetically related sedimentary formations. These geodynamic
processes taking place during the Cretaceous and Early Paleo-
gene in BARB environments produced the main tectonostrati-
graphic units of the VZ, which were backthrusted during the
Eocene main deformational event onto the DOZ.
In such an interpretation, the Dinaridic ophiolites represent
fragments of Mesozoic oceanic crust generated over a period
of ca. 150 Ma. They are the product of a two-stage evolution:
1) Older ophiolites included in the DOZ originating in open-
58 SLOVENEC
and PAMIĆ
ocean environments were obducted during the Tithonian-
Berriasian oceanic subduction. 2) Younger ophiolites, origi-
nating in BARB environments and their obduction was re-
lated to the main Eocene deformational event, that is, the
Eurasian (Tisia and Moesia)-African (Apulia) continental
collision.
Despite the complex structure of the Dinarides, the DOZ
and VZ can be almost continuously traced along their strike
for about 700 km. On the basis of the available outcrops
and seismic and deep drilling data the VZ units, although
mainly covered by sediments of the South Pannonian Ba-
sin, can be traced along strike up to the northwesternmost
parts of the Dinarides. The outcrops of the VZ lithologies
are only a few tens of kilometres from the easternmost Peri-
adriatic Lineament (Pamić 1993; Pamić & Tomljenović
1998).
In this geodynamic interpretation of the Dinaridic ophio-
lites, it is not easy to explain the present position of the
ophiolites of the Medvednica Mt and the whole ZMTZ. An
undocumented opinion prevailed that these ophiolites have
their root in the northwestern part of the Internal Dinarides
from where they were tectonically transported along the
Zagreb-Zemplin transcurrent fault system during the Tertia-
ry post-orogenic tectonic phases (Tomljenović 1995; Pamić
1997 and others).
However, emplacement of the ophiolites of the Medved-
nica Mt and the surrounding mountains must have been re-
lated to the geodynamic evolution of the ZMTZ in which
they are included. The ZMTZ is a transitional zone com-
posed of mixed allochthonous units of the Alps and Dinar-
ides. According to the current widely accepted opinion, it is
believed that the transitional ZMTZ originated by extrusion
(escape) tectonics (Kázmér & Kovács 1985; Ratschbacher
et al. 1991) during the post-orogenic evolution of the Dinar-
ides and Alps. According to this interpretation after Eocene
compression and collision, and uplift of the Dinarides and
Alps started the NNW rotation of Apulia and its indenting
into the southern Eurasian margin. These tectonic move-
ments gave rise to strong N-S shortage of the Alpine tec-
tonostratigraphic units in the adjoining area of the Southern
and Eastern Alps, e.g. Periadriatic Lineament region
amounting to 200—500 km (Coward & Dietrich 1989; Laub-
scher 1971; Ziegler et al. 1996). The Apulian indenting is
reflected in transpression processes manifested in strong
dextral strike slip faulting, that is, the horizontal eastward
tectonic transport toward the western parts of the Pannon-
ian Basin. According to such an interpretation the allochth-
onous Paleozoic and Mesozoic blocks of the Medvednica
Mt and the whole ZMTZ might have had their roots in the
wider Periadriatic area. It is very probable that in the same
root area, before the mechanism of escape tectonics started
to operate, lithologies of the VZ were also included.
Acknowledgment: This paper was financially supported by
the Ministry of Science and Technology of the Republic of
Croatia (Grants: 195004 and 018101001). The authors are
grateful to S. Kovács and an anonymous referees for their
valuable suggestions which improved the quality of the
manuscript.
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