The Alpine-Carpathian-Dinaridic Orogenic System Correlation And

8/3/2019 The Alpine-Carpathian-Dinaridic Orogenic System Correlation And

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ABSTRACT

A correlation of tectonic units of the Alpine-Carpathian-Dinaridic system oforogens, including the substrate of the Pannonian and Transylvanian basins, ispresented in the form of a map. Combined with a series of crustal-scale crosssections this correlation of tectonic units yields a clearer picture of the three-dimensional architecture of this system of orogens that owes its considerable

complexity to multiple overprinting of earlier by younger deformations.The synthesis advanced here indicates that none of the branches of theAlpine Tethys and Neotethys extended eastward into the Dobrogea Orogen.Instead, the main branch of the Alpine Tethys linked up with the Meliata-Maliac-Vardar branch of the Neotethys into the area of the present-day In-ner Dinarides. More easterly and subsidiary branches of the Alpine Tethysseparated Tisza completely, and Dacia partially, from the European continent.Remnants of the Triassic parts of Neotethys (Meliata-Maliac) are preservedonly as ophiolitic mlanges present below obducted Jurassic Neotethyan(Vardar) ophiolites. The opening of the Alpine Tethys was largely contem-poraneous with the Latest Jurassic to Early Cretaceous obduction of partsof the Jurassic Vardar ophiolites. Closure of the Meliata-Maliac Ocean in theAlps and West Carpathians led to Cretaceous-age orogeny associated with aneclogitic overprint of the adjacent continental margin. The Triassic Meliata-Maliac and Jurassic Western and Eastern Vardar ophiolites were derived fromone single branch of Neotethys: the Meliata-Maliac-Vardar Ocean. Complex

geometries resulting from out-of-sequence thrusting during Cretaceous andCenozoic orogenic phases underlay a variety of multi-ocean hypotheses, thatwere advanced in the literature and that we regard as incompatible with thefield evidence.

The present-day configuration of tectonic units suggests that a former

connection between ophiolitic units in West Carpathians and Dinarides wasdisrupted by substantial Miocene-age dislocations along the Mid-HungarianFault Zone, hiding a former lateral change in subduction polarity betweenWest Carpathians and Dinarides. The SW-facing Dinaridic Orogen, mainlystructured in Cretaceous and Palaeogene times, was juxtaposed with the Tiszaand Dacia Mega-Units along a NW-dipping suture (Sava Zone) in latest Cre-taceous to Palaeogene times. The Dacia Mega-Unit (East and South Carpath-ian Orogen, including the Carpatho-Balkan Orogen and the Biharia nappesystem of the Apuseni Mountains), was essentially consolidated by E-facingnappe stacking during an Early Cretaceous orogeny, while the adjacent TiszaMega-Unit formed by NW-directed thrusting (in present-day coordinates) inLate Cretaceous times. The polyphase and multi-directional Cretaceous toNeogene deformation history of the Dinarides was preceded by the obductionof Vardar ophiolites onto to the Adriatic margin (Western Vardar OphioliticUnit) and parts of the European margin (Eastern Vardar Ophiolitic Unit)during Late Jurassic to Early Cretaceous times.

1. Introduction

Our analysis of the Alpine-Carpathian-Dinaridic system oforogens including the Pannonian and Transylvanian basins,and of its complex temporal and spatial evolution, is basedon a tectonic map that includes the entire system and crossesmany national boundaries. This map, presented in Plate 1, wasconstructed by compiling of available geological maps and sub-surface information for those parts of the system covered by

very thick Mio-Pliocene (in case of the Pannonian basin) ormid-Cretaceous to Late Miocene deposits (in case of the Tran-sylvanian basin).

The map leads to a better understanding of the mobile beltsformed during Late Jurassic, Cretaceous and Cenozoic timesthat are characterized by extreme changes along strike, includ-ing changes in subduction polarity (Alpine-Carpathian polarityvs. Dinaridic polarity; e.g. Laubscher 1971; Schmid et al. 2004b;Kissling et al. 2006). In addition it serves as a base map for

The Alpine-Carpathian-Dinaridic orogenic system: correlation andevolution of tectonic units

STEFAN M. SCHMID1, DANIEL BERNOULLI1, BERNHARD FGENSCHUH2, LIVIU MATENCO3, SENECIO SCHEFER1,RALF SCHUSTER4, MATTHIAS TISCHLER1 & KAMIL USTASZEWSKI1

Key words: tectonics, collisional Orogens, Ophiolites, alps, Carpathians, Dinarides

1661-8726/08/01013945DOI 10.1007/s00015-008-1247-3Birkhuser Verlag, Basel, 2008

Swiss J. Geosci. 101 (2008) 139183

1 Geologisch-Palontologisches Institut, Basel University, Bernoullistr. 35, 4058 Basel, Switzerland. E-mail: [email protected] Geology and Palaeontology, Innsbruck University, Innrain 52 f, A-6020 Innsbruck, Austria.3 Netherlands Centre for Integrated Solid Earth Sciences, Vrije Universiteit, Faculty of Earth and Life Sciences, De Boelelaan 1085, 1081 HV Amsterdam,The Netherlands. E-mail: [email protected]

4 Geologische Bundesanstalt, Neulinggasse 38, A-1030 Wien, Austria. E-mail: [email protected]

Alps-Carpathians-Dinarides 139


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140 S. M. Schmid et al.

future palinspastic reconstructions that are required to arriveat realistic paleogeographic and paleotectonic reconstructions.The first obvious step towards this goal consists in establishingthe Early Miocene geometry of the various tectonic units of thesystem. A retro-deformation of the very substantial Miocenerotations and translations was first sketched by the pioneeringwork of Balla (1987). Subsequent attempts included kinematicinversion of pre-Miocene rotations and translations in order toestablish the motion and deformation of the different tectono-stratigraphic units involved in the system during the earlierPalaeogene and/or Cretaceous orogenic phases (i.e. Royden& Baldi 1988; Csontos et al. 1992; Csontos 1995; Fodor et al.1999; Csontos & Vrs 2004). Moreover, numerous contrast-ing reconstructions have been advanced for the opening andclosure of the different oceanic domains that form part of Neo-Tethys, including its Alpine branch (e.g. Sndulescu 1980, 1988;Golonka 2004; Haas & Pero 2004; Stampfli & Borel 2004).

All attempts at retro-deformation for Palaeogene and/orMesozoic times must consider the present-day complex three-dimensional configuration of the entire Alpine-Carpathian-Di-

naridic system. Our maps and profiles attempt to provide cor-relations on the basis of which the paleogeographic and paleo-tectonic evolution can be deduced. The data presented here arederived from literature studies and extensive own fieldwork.Naturally the divisions shown on the map (Plate 1) build on ex-isting compilations (e.g. Sndulescu 1975; Channell & Horvath1976; Royden & Horvath 1988; Csontos & Vrs 2004; Kovcset al. 2004), but use only primary data and own observations fordefining the individual units.

Starting with a brief overview of the first order tectonic el-ements, we proceed with detailed descriptions of the individ-ual tectonic units. In support of these descriptions, a series ofcrustal-scale profiles will be presented. These provide a three-

dimensional picture of this complex system of orogens, whichformed by a long-lasting evolution, that started in Late Jurassictimes and is still going on today (Weber et al. 2005).

2. Method of map compilation

The tectonic map of the Carpathian-Balkan Mountain Sys-tems edited by Mahel (1973) served as base map for the en-tire area covered by our compilation (Plate 1), apart from theAlps, for which we used a simplified version of the tectonic mappublished by Schmid et al. (2004a). The tectonic map by Ma-hel (1973) was progressively updated by new data. The mostimportant sources of information are referenced. Longitudesand latitudes are marked at the margins of Plate 1. A versionof this map giving 1 longitude and latitude grid points can beobtained from the first author. Figure 1 gives geographic andgeological names mentioned in the text.

The Pannonian and Transylvanian basin fills, covering largeparts of the Alpine-Carpathian-Dinaridic tectonic units, mustbe removed to understand the correlations and relationshipsbetween the different units. The sedimentary fill of these ba-sins is regarded as post-tectonic as it rests unconformably on

parts of the Alpine, Carpathian and Dinaridic orogens; how-ever, these sediments were later deformed in many places bydeformation associated with basin formation and inversion.In Plate 1, white lines give the outlines of the Pannonian andTransylvanian Basin, and of numerous inselbergs in whichunits of the basin floor are exposed. Buried tectonic boundar-ies were drawn by projecting their suspected or known positionto the surface. However, in many places the location of tectonicboundaries below the basin fill remains rather uncertain.

In the Pannonian basin, the post-tectonic fill conceals manycrucial contacts between Alpine, Dinaride and Carpathian tec-tonic units. The basin fill mostly consists of Miocene sedimentsup to 6 km thick (see overview given in Haas 2001). The sedi-ments of the post-tectonic cover of the Pannonian basin typi-cally start with either Late Cretaceous or Palaeogene strata.

Note that we assigned the Cretaceous to Eocene SzolnokFlysch (Haas 2001) to the bedrock-units rather than to thepost-tectonic fill of the Pannonian basin, because the evolu-tion of this flysch basin clearly differs from that of the rest ofthe Pannonian Basin (e.g. Baldi & Baldi-Becke 1985). In our

compilation the Szolnok Flysch is correlated with similar unitsoccurring in the Pienides of Northern Romania (Sndulescuet al. 1981a; Tischler 2005; Tischler et al. 2007) and in the Pen-nine units known from the subsurface of the East Slovak Ba-sin (Iaovce-Krichevo Unit; i.e. Sotk et al. 1999). The subsur-face information for this basin largely stems from drill holes(e.g. Flop & Dank 1987) and from seismic data (e.g. Tari etal. 1999).

The Late Cretaceous to Miocene fill of the TransylvanianBasin (e.g. Huismans et al. 1997; de Broucker et al. 1998) cov-ers many of the more internal units of the East Carpathiansand Apuseni Mountains. Only recently, a wealth of informationfrom the floor of this basin became available from hydrocar-

bon exploration (e.g. Kreszek & Bally 2006). Much of this asyet largely unpublished information, consisting of seismic re-flection data partly calibrated by bore holes was used duringcompilation of Plate 1.

The crustal-scale cross-sections given in Plates 2 & 3 wereconstructed during the compilation the map (Plate 1). Profileconstruction led to additional insights that significantly im-proved parts of the map. Note however, that the deeper por-tions of the crustal-scale profiles in Plates 2 & 3 are not con-strained by geophysical or borehole data.

3. Overview of the major groups of tectono-stratigraphic units

The tectono-stratigraphic units described in detail below defineeight groups (Plate 1). Before going into greater details regard-ing map compilation and individual tectonic units, these groupsare briefly introduced.

3.1. Undeformed foreland

The northern and eastern flexural foredeep of the Alps andCarpathians (External Foredeep) is variably floored by Va-


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GEOGRAPHICALFEATURESANDLOCALGEOLOGICALNAMES

Bohemian

Bmamassiv

mv

EastEuropean

EEoPlatform

Paom

Focsani

Fodepression

d

eo

IntramoesianF

.

Intram

oesianF

.

Moesian

MaPlatform

Paom

Peceneag

a-Cam

enaF

Trotu

sF

.

Totus

F

Istria

Isa

Ranovac&Vlasinaunits

RabaF.

Split-Karlov

acF.

Cerna-Jiu

F.

B.

-

D.

V.

Fa

ult

-

Balato

n

F.Mid-H

ungarianfaultzone

Giud

icarie

Giudiar

eGi

udica

rie

Bohemian

massiv

Istria

Bkk

Mts.

Darn

o

UpponyMts.

North

Apuseni

Mts.

Bihor

Mts.T

rascau

Mts.

Codru

Mts.

South

Apuseni

Mts.

CentralWestCarpathians

Inner

WestCarpathians

NorthernCalcareousAlps

D

anubianwindow

Dinarico.

W.Vardaro.

Geticdepression

Engadine

window

Tauern

window

EastEuropean

Platform

Focsani

depression

EastSlo

vakb

asin

IntramoesianF

.

LittleHungarian

Plain

Viennab

asin

Transylvanian

basin

Transylvanian

nappes

Magura

fly

sch

Moesian

Platform

North

Dobro

gea

oro

gen

Pece

neag

a-Camena

F.

Pienides

Rodna

horst

E as t

C a rp a th ians

Sou

th

Carpathi

ans

Sav

a

Zone

W

es

tC

a

r

p

a

t

h

i

a

n

s

Mid-H

ungarianl

ine

Trans

danubianr

ange

L.

Balaton

Algy

basement

high

FruskaGora

CentralBalkanu.

SrednaGora

W

est

Balkan

unit

Jastrebac

Korab-Pelagonian

Osogovo-Lisetscorecomplex

EastBalkanu.

Drauzug

Drin

a-Iv

anj ica

Grauwackenzone

Hainburghills

Leitha

MalKarpatyMts.

Hur

ban

ovo-D

isenoF

.

Jadar

Kopaonik

Studenica

Durmitor

Mtn.

Zlatibor

Mtn.

MecsekMts.

VillanyMts.

Morava

unit

Mird

itao.

Moslavac

kaGora

MedvednicaGora P

apuk

Motajica

PozeskaGora

Bosn

ariv

er

Prosara

Kozara

Ne

ksen

yF.

Rechnitzwindow

South

Tra

nsy

lva n

ia n

F.

Trotu

sF

.

HighKa

rst

Zemplin

Szendr

Periad

riati

c

Dalmatian

Zone

TimokF.

Fig.1.Indexmapofge

ographicandgeologicalnamesusedinthetex

t(seealsoPlate1).


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riscan, Caledonian or Precambrian basement that is overlainby little or undeformed Mesozoic to Cenozoic sediments. TheEast European and Scythian platforms were essentially con-solidated during Precambrian times. More recently, the Scyth-ian Platform was re-interpreted as the passive margin of theEast European craton that was strongly involved in latest Pre-cambrian to Early Paleozoic (pre-Variscan) tectonic events andthat was reactivated during younger and less important events(Stephenson et al. 2004; Saintot et al. 2006). The SW bound-ary of the East European Platform (Precambrian platformin Plate 1) coincides with the NWSE striking Teisseyre-Torn-quist Zone that was repeatedly reactivated during Late Pa-leozoic, Mesozoic and early Cenozoic times (Ziegler 1990).The Pre-Mesozoic basement of areas located to the SW of theTornquist-Teisseyre Zone consists of an array of essentiallyGondwana-derived terranes that were accreted to the marginof the East European craton during the Caledonian and Va-riscan orogenies (Ziegler 1981, 1990; Pharaoh et al. 2006). TheMoesian Platform, for example, underwent significant Variscandeformation and was accreted to the Scythian Platform during

the Late Carboniferous (Seghedi 2001). In the process of this,the latter also became overprinted by Variscan deformation(e.g. Zonenshain et al. 1990).

The most external units of the allochthonous East Carpath-ian Miocene flysch belt partly override the Teisseyre-TornquistZone. Following an Early Triassic rifting event, the MoesianBlock was probably separated from the Scythian Platform alongthe SE-most segment of the Teisseyre-Tornquist Zone, only tobe re-accreted to it during the Jurassic Cimmerian North Do-brogean orogeny (e.g. Murgoci 1929; Seghedi 2001) that occu-pies a special position within the Alpine-Carpathian-Dinaridicsystem (Plate 1). Along the SE-most segment of the Teisseyre-Tornquist Line the Moesian Platform and the North Dobrogea

Orogen were welded along the Peceneaga-Camena Fault Zonebefore the end of the Early Cretaceous (e.g. Murgoci 1915;Hippolyte 2002) when intense tectonic activity along it ceased.Both units are separated by the pre-Neogene Trotus fault fromthe Scythian Platform (Sndulescu & Visarion 1988).

With respect to the post-Early Cretaceous tectonic activ-ity, the North Dobrogea Orogen, and the Moesian and Scyth-ian platforms are considered as undeformed foreland. Onlyminor reactivation along faults shown by thick black lines inPlate 1 occurred in Miocene-Quaternary times (Trpoanc etal. 2003; Leever et al. 2006). The northern fault segment nearBacau (Plate 1), however, is not part of the pre-Neogene Trotusfault, but a Quaternary northern splay of the latter (see Ma-tenco et al. 2007).

The term Adriatic plate often refers to the undeformedlithospheric plate or subplate (Channell & Horvath 1976)that includes the present day undeformed areas of Istria andthe Apulian carbonate platform and is framed by the externalthrust belts of Southern Alps, Dinarides and Apennines. Thispart of the Adriatic plate acted as a rigid indenter during itscollisional interaction with the Alpine and Dinaridic orogensto the north and east (Fig. 2c), respectively (e.g. Channell et

al. 1979; Schmid & Kissling 2000; Pinter et al. 2005). However,note that the term Adria is also used for denoting the pa-leogeographical affiliation of structural entities that had origi-nally formed part of a larger Adriatic (or African/Adriatic;Channell & Horvath 1976) promontory or micro-continent butlater became involved in its fringing folded belts (Dercourt etal. 1986). In this contribution the term Adria and Adriaticwill therefore be used for the broader paleogeographical realmthat flanked the Alpine Tethys to the south (Apulia in thesense of Schmid et al. 2004a), rather than just for the present-day rigid Adriatic plate. Structural entities that later becameincorporated into the Alpine-Carpathian-Dinaridic system willbe referred to as Adria-derived.

3.2. Miocene external thrust belt:

This thrust belt is the only structural element that extendscontinuously along the margin of the Alpine-Carpathian oro-genic system from the Western Alps through the Western andEastern Carpathians into the South Carpathians where it ends

(Plate 1). In the Carpathians this foreland fold-and-thrust-belt(i.e. Sndulescu et al. 1981a,b; Morley 1996; Matenco & Ber-totti 2000; Krzywiec 2001; Oszczypko 2006) formed during theNeogene when the ALCAPA (Alps-Carpathians-Pannonia)and Tisza-Dacia Mega-Units moved to the northeast and eastinto an eastward concave embayment in the European fore-land. Their soft collision with the European foreland (e.g. Balla1987) was triggered by a combination of lateral extrusion (e.g.Ratschbacher et al. 1991a,b) and, more importantly, by theretreat (roll-back) of a subducting eastern European oceaniclithospheric slab (in the sense of Royden 1988, 1993). Calc-al-kaline and alkaline magmatism within the Carpathian arc wasclosely related to subduction, slab-rollback, slab-detachment

and extension in the overriding plate (Nemok et al. 1998;Wortel & Spakman 2000; Seghedi et al. 2004). In the SouthCarpathians, where the Miocene fold-and-thrust-belt ends,the inner units of the South Carpathians were juxtaposed withthe Moesian Platform during Palaeogene-Miocene time in re-sponse to a combination of strike-slip movements along curvedfault systems (Plate 1) and by oblique thrusting (Ratschbacheret al. 1993; Rbgia & Matenco 1999; Fgenschuh & Schmid2005; Rbgia et al. 2007).

3.3. Europe-derived units in the Alps and in the Dacia

Mega-Unit

This rather heterogeneous group of tectonic units denotes al-lochthonous units, commonly interpreted to have been derivedfrom the European continent. In the Alps these units comprisethe Helvetic, Ultrahelvetic and Subpenninic nappes, as well asnappes derived from the continental Brianonnais fragmentthat broke off Europe (Fig. 2c) in the Early Cretaceous in con-

junction with opening of a partly oceanic scar (Valais ocean, e.g.Schmid et al. 2004a). In the Carpathians analogous allochtho-nous units, but not considered as the direct lateral continuation


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DDM

M: Moesia

D: Dacia

T: Tisza

T

S. AlpsAdri

aticindenter

Iberia-Brianconnais

SBABASBA

SBA: Sava Back-Arc Ocean

A: ALCAPA

A

Eoalpine eclogites

Vala

is

P.-Lig

uria

P -L

iguria

Oman

Oman

NEOT

ETHY

S

N E O T ET H Y S

P.-Lig

uria

OmanA L P I N E T E T H YS

NEOT

ETHY

SG

V

0 1000 km

oceanic lithosphere

Late CretaceousSantonian 84 Ma

Dina

rides

c

Dinarid

es

AL

CAP

A

NEOTETHYS

ALPINE TETHYS

Moesia

S.Alps

Dacia

RhodopesTisza

0 1000 km

Meliata-Maliac

Ocean

Piemont-Liguria

Ocean

G

V

Eastern Vardar

Ophiolitic Unit

Ceahlau-Severin Ocean

Western Vardar

Ophiolitic Unit

Triassic ocean floor

Neotethys lower plateand Alpine Tethys

Neotethys upper plate

Jurassic ocean floor:

Late JurassicOxfordian 156 Ma

b

Iran

Moesia

Rhodopes

PaleotethysaleotethysPaleotethys

Drama

N E O T E T H Y S

Dacia

Tisza

N Dobrogea Rift

Melia

ta-M

alia

cOce

an

Extern

alD

inarid

es

S.Alps

G

V

1000 km0Late TriassicCarnian 220 Ma

A

L

CAP

A

Triassic ocean floor

a

Fig. 2. Schematic palinspastic sketches visualizingconcepts presented in the text and incorporatingideas mainly taken from Frisch (1979), Frank (1987),Dercourt et al. (1993), Stampfli (1993), Sandulescu(1994), Stampfli et al. (2001), Marroni et al. (2002)& Schmid et al. (2004a). Positions and projections ofthe outlines of the European and African continents

are those given by Stampfli et al. (2001), except forthe coastlines of the Adriatic Sea that we assume toremain firmly attached to the African continent untilCretaceous times. G: Geneva; V: Vienna.a) Opening of the Neotethyan Meliata-Maliac Oceanin the Triassic (Carnian, 220 Ma).b) Opening of the Piemont-Liguria Ocean (AlpineTethys), leading to the separation of the Adria Plate(including the future Southern Alps and ALCAPA),as well as the Tisza and Dacia Mega-Units from theEuropean continent in Oxfordian time (156 Ma).Simultaneously, the Triassic Meliata-Maliac Oceanis being subducted south-eastward below the upperplate Jurassic parts of Neotethys (future Westernand Eastern Vardar Ophiolitic Units). The latter areabout to become obducted onto the Adria margin,i.e. the future Dinarides, as well as onto the DaciaMega-Unit.c) In Santonian times (84 Ma) the two branchesof the Alpine Tethys (Valais and Piemont-LiguriaOceans) connect via the Carpathian embayment withyounger, i.e. Cretaceous-age branches of Neotethyssuch as the back-arc ocean that will form the futureSava Zone. Note the onset of northward movementof the Adriatic indenter, contemporaneous with theopening of the East Mediterranean Ocean and thenorthward drift of Africa.


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of their Alpine counterparts, define what is commonly referredto as the Dacia (Fig. 2) Mega-Unit or terrane in the Hungarianliterature (e.g. Csontos & Vrs 2004). Parts of this Mega-Unitconsist of an assemblage of far-travelled nappes (Infrabuco-vinian-Getic-Kraishte-Sredna Gora and Serbo-Macedonian-Supragetic-Subbucovinian-Bucovinian-Biharia units; also re-ferred to as Median Dacides by Sndulescu 1994) that werederived from blocks, which were detached from the Europeanmargin during Jurassic rifting (Fig. 2b). Whilst oceanic litho-sphere of the Ceahlau-Severin Ocean separated parts of theseunits from Europe, it is unlikely that oceanic lithosphere hadseparated other units from the European margin. It appearsthat some nappes, such as the Danubian nappes of the SouthCarpathians (also referred to as Marginal Dacides; Sndulescu1994; Krutner 1996), and units such as the Central Balkan andPrebalkan units of Bulgaria (Georgiev et al. 2001) were directlyscraped off the European margin (Moesian Platform; Fig. 1) inresponse to strong collisional coupling of the orogenic wedgeand the foreland (Ziegler et al. 1995).

3.4. Inner Balkanides

While the External Balkanides (Prebalkan, Central Balkan andSredna Gora units; e.g. Ivanov 1988) can be correlated withother units that form part of Dacia, the Inner Balkanides (in-ner with respect to the Moesian foreland of the Balkanides)form a distinct group of tectonic elements whose origin re-mains controversial. Two of these units, that are not the focusof our analysis, reach the southern margin of the map of Plate 1.These are: (i) the Strandja Unit (e.g. Georgiev et al. 2001; Okayet al. 2001) that was strongly deformed, metamorphosed andthrust northward during Late Jurassic to Early Cretaceous timeand represents a fragment of an older (Cimmerian) orogen,

located near the Paleotethys-Eurasia-Gondwana triple point,that was later incorporated into the N-vergent Balkan Orogen;(ii) The Rhodope core complex delimited to the north and westby Cenozoic normal and strike-slip faults (e.g. Sokoutis et al.1993; Kilias et al. 1999; Brun & Sokoutis 2007). Its boundingCenozoic faults post-date Early Jurassic to Cretaceous top-S(SW) nappe stacking and high- to ultrahigh-pressure metamor-phism within the gneissic units of the Rhodope Mountains, andthey obscure the original relationships of the Rhodope corecomplex with the neighbouring units (Burg et al. 1996; Turpaud2006; Perraki et al. 2006; Mposkos & Krohe 2006). The struc-turally lower unit within the Rhodope core complex possiblyrepresents a terrane (Drama terrane in Fig. 2a) that collidedwith the rest of the Rhodopian units in Jurassic times alongthe eclogite-bearing Nestos suture (Turpaud 2006; Bauer et al.2007).

3.5. Units with mixed European and Adriatic affinities: Tisza

The crustal fragment, which presently constitutes the nappesequence of the Tisza Mega-Unit, was separated from Europeduring the Middle Jurassic (Fig. 2b), presumably in conjunction

with the opening of the eastern parts of the Alpine Tethys (orPiemont-Liguria Ocean; Haas & Pero 2004). With the openingof an ocean between Europe and Tisza, the latter moved into apaleogeographic position comparable to that of the Austroal-pine or Southalpine realm. The facies of the post-rift sedimentswithin Tisza, such as radiolarites and pelagic Maiolica-typelimestones, exhibits Adriatic affinities; the faunal provincesare of the Mediterranean type (e.g. Vrs 1977, 1993; Lupu1984; Haas & Pero 2004). Much of the tectonic units of Tisza(Mecsek, Bihor and Codru nappe systems) are only exposed inisolated and rather small inselbergs within the Pannonian plain(i.e. Mecsek nappe system in the Mecsek Mountains in Hun-gary; Haas 2001). A coherent nappe sequence is only present inthe North Apuseni Mountains of Romania (Bihor and Codrunappe systems; Balintoni 1994). The tectonically highest andmost internal nappe system of the North Apuseni Mountainsis the Biharia nappe system (Balintoni 1994), traditionally con-sidered as a constituent of Tisza (Csontos & Vrs 2004), i.e.the Internal Dacides (Sndulescu 1984; Balintoni 1994). How-ever, we correlate this Biharia nappe system with the Bucovin-

ian nappes (Plate 1) and hence attribute it to Dacia (i.e. theMedian Dacides in the sense of Sndulescu 1984) for reasonsdiscussed later.

3.6. Adria-derived far-travelled nappes of the internal Alps and

the West Carpathians (ALCAPA Mega-Unit):

This group of tectonic elements is referred to as the Austroal-pine nappes in the Alps (e.g. Schmid et al. 2004a) and as theCentral and Inner West Carpathians in the Carpathians (e.g.Plaienka et al. 1997a,b). In the Alpine literature these elementsare often referred to as being derived from Adria (or Apuliain the sense of Schmid et al. 2004a). In the Alps this implies that

their initial paleogeographical position was to the south of thePiemont-Liguria Ocean, the main branch of the Alpine Tethys(Fig. 2b). Presently, these elements represent far-travelled thincrustal slices found in an upper plate position above the UpperPenninic (or Vahic in case of the West Carpathians) suture zoneand the underlying Europe-derived elements of the Alps andWest Carpathians.

Note, however, that the notion of Adria as a single paleo-geographic entity becomes problematic in the easternmost Alpsand the adjacent Carpathians and Dinarides owing to the oc-currence of branches of a second group of oceanic realms thatformed part of the so-called Neotethys (e.g. Haas 2001). Neo-tethys formed an eastward opening oceanic embayment in theAdria paleogeographical realm that had opened during Triassictimes (Fig. 2a) and is referred to as Meliata Ocean in the Alpsand Carpathians (i.e. Channell & Kozur 1997), but as MaliacOcean in the Hellenides (e.g. Stampfli & Borel 2004). Hencethe Austroalpine nappes and their extension into the West Car-pathians include tectonic elements that were positioned north,west and south of the Meliata-Maliac Ocean (Fig. 2; Schmid etal. 2004a). Sea-floor spreading continued in Neotethys duringthe Jurassic, but the connections between the various oceanic


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realms formed in Jurassic times with those of the Alpine Tethysare not yet properly understood; Figure 2 merely represents anattempt to satisfy the data compiled in this work.

3.7. Adria-derived thrust sheets: Southern Alps and Dinarides

The units that comprise parts of the Adria paleogeographicrealm presently located south of the Periadriatic Line and itseastern continuation (Balaton Line), i.e. south of the ALCAPAMega-Unit, constitute the Southern Alps and all the non-ophi-olitic tectonic units of the Dinarides, including a fragment dislo-cated along the Mid-Hungarian Fault Zone (Bkk Mountains ofNorthern Hungary). During the Triassic these units were also lo-cated south (or rather southwest, Fig. 2a) of the Meliata Ocean,and thus they were derived from the northern passive margin ofAdria that faced the Meliata-Maliac-Vardar branch of Neote-thys. In our view the Drina-Ivanjica, Korab-Pelagonian, Bkk,Jadar and Kopaonik terranes or blocks (e.g. Dimitrijevi2001; Karamata 2006) all represent units that structurally under-lie remnants of what we refer to as Vardar Ocean in this contri-

bution, i.e. Neotethyan ophiolites of Jurassic age that were ob-ducted onto the Adria margin during the Late Jurassic (Fig. 2b).Presently, the most external northern Dinaridic units are sepa-rated from the Southern Alps by the eastward continuation of asouth verging dextrally transpressive thrust front, which formedat a late stage (Mio-Pliocene) in the tectonic history of the Al-pine-Carpathian-Dinaridic system. From northeastern Italy andSlovenia we trace this transpressive thrust front into Hungary asfar to the east as south of lake Balaton (Plate 1).

In summary, this group of units was derived from continen-tal crustal domains located far to the south of the Alpine Tethys,and even south (or southwest in case of the Southern Alps) ofthe Neotethys (Fig. 2). Note that many of the detached units of

this group overlie an autochthonous basement that is presentlystill associated with its lithospheric underpinnings (Schmid etal. 2004b); they thus represent deformed parts of the present-day Adriatic plate.

3.8. Ophiolites and accretionary prisms

This group of tectonic units is characterized by ophiolitic and/orflysch-type rock associations and is extremely heterogeneous. Itcomprises tectonic elements, some of which can be traced alongstrike over long distances; they often define important suturesand/or important mobile zones between and occasionally alsowithin the above described groups of tectonic elements.

Here we will use the term ophiolite in a wider sense, thatis we do not restrict the term to rock associations formed atmid-ocean ridges. We also include other types of magmatic andsedimentary rock associations that are indicative of the pres-ence of former oceanic lithosphere. Hence we include, for ex-ample, supra-subduction ophiolites and/or subduction-relatedvolcanic arc rocks that developed within pre-existing oceaniccrust (see discussion on ophiolite models in Robertson 2002).Moreover, we use the term ocean as denoting paleogeo-

graphic domains we suspect to have been floored by oceanicrather than continental lithosphere.

It is important to realize, however, that in some cases theophiolites were obducted as thrust sheets and hence do notmark the location of a deeper suture zone (e.g. Western Var-dar Ophiolitic Unit of Plate 1). Others (e.g. the remnants ofthe Meliata-Maliac Ocean) are only found as blocks withinmlange formations beneath coherent ophiolitic thrust sheetssuch as the Western Vardar Ophiolitic Unit that were obductedduring the Late Jurassic (Fig. 2b). Some ophiolitic mlangeand obducted ophiolites became subsequently involved in thedevelopment of composite thrust sheets or nappes, consistingof continental units and previously obducted ophiolites thatformed by out-of-sequence thrusting during Cretaceous andCenozoic orogenic cycles.

The interrelationships between individual elements of thisgroup of tectonic units still remain uncertain in many cases.This is due to a poor understanding on how Miocene defor-mations and even more so Palaeogene and Cretaceous defor-mations and translations ought to be retro-deformed. In this

sense, all existing paleogeographic reconstructions for the Al-pine-Carpathian-Dinaridic area for Triassic, Jurassic or Creta-ceous times, of course including those presented in Fig. 2, mustbe regarded as purely speculative.

These uncertainties necessitate the continued use of manyregional or local names for these ophiolitic and/or accretion-ary wedge units (see discussion by Zacher & Lupu 1999).Nevertheless, we find it convenient to use the terms AlpineTethys and Neotethys in order to denote two groups of oceansthat began to open in Permian (?) to Mesozoic times in con-

junction with the break-up of Pangaea (e.g. Stampfli & Borel2004).

We use the term Alpine Tethys collectively for all oceanic

realms in the Alpine-Carpathian domain, the opening of whichwas kinematically directly linked to sea-floor spreading in theCentral Atlantic (Figs. 2b and 2c) that was initiated in late EarlyJurassic times (Favre & Stampfli 1992). The term Neotethysis used for all oceanic realms located in an area southeast of theAlpine Tethys and the future Western Alps that opened duringand after the Permian to Triassic closure of Paleotethys, whichat the end of the Variscan orogeny had still separated Gond-wana and Laurussia (e.g. Stampfli & Borel 2004). Opening ofthe oceanic Neotethys basins was neither temporally nor kine-matically linked to the opening of the Alpine Tethys. In contrastto the Alpine Tethys, parts of Neotethys were consumed in thecontext of obduction during Late Jurassic times (Fig. 2b), witha kinematic link to the opening of the Central Atlantic (e.g.Dinaridic ophiolites; Laubscher 1971; Pami et al. 2002a), whileothers opened later during the Cretaceous (Sava Back-ArcOphiolites of Fig. 2c). Yet it is debatable whether during theJurassic the oceanic realms of the Alpine Tethys and Neotethyswere completely separated or linked somewhere in the Alpine-Carpathian-Dinaridic realm (as proposed in Fig. 2b). However,we will present arguments to propose that Cretaceous-age oce-anic branches of Neotethys (such as the Sava Back-Arc Ocean,


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Fig. 2c) were directly linked with the Alpine Tethys along thepresent-day Sava-Zone mapped in Plate 1.

We attribute the following oceanic basins to the Alpine Te-thys: (i) The Valais, Rhenodanubian and Magura flysch unitsforming a northern branch (Schnabel 1992; Plaienka 2003;Schmid et al. 2004a), and (ii) the Piemont-Liguria-Vahicum-Pieniny Klippen Belt (Birkenmajer 1986; Plaienka 1995a)units defining a southern branch. Both branches were at leastpartly separated by the continental Brianonnais fragment ofthe Western Alps (Frisch 1979; Stampfli 1993) and possibly bysmaller analogous units found as relics in the Pieniny KlippenBelt of the West Carpathians (Birkenmajer 1986; Trmpy 1988)that probably were not directly linked with the Brianonnais.

According to our interpretation the Magura Flysch and thePiemont-Liguria-elements of the Alpine Tethys can be tracedSE-ward via the Iaovce-Kriscevo Unit of Eastern Slovakiaand the Ukraine (Sotk et al. 1993, 1999) into the flysch unitsreferred to as the Pienides of northern Romania (Sndulescuet al. 1981a). In map view, the latter form a tight E-verging arc(Plate 1) and were thrust onto the Tisza-Dacia Mega-units dur-

ing Miocene times (Fig. 3; Tischler et al. 2007). We propose toconnect the Pienides with the Szolnok Flysch in the subsur-face of the Pannonian Basin. The ophiolitic Szolnok Flyschbelt (ophiolite-bearing Intrapannonian belt of Channell et al.1979) can be traced westward along the Mid-Hungarian FaultZone towards Zagreb where it links up with the ophiolite-bear-ing Sava Zone (Plate 1). This zone consists of a belt of ophi-olitic (relics of the Sava Back-Arc Ocean, Fig. 2c), magmaticand metamorphic rocks that extends SE-ward from Zagreb toBelgrade (North-western Vardar Zone of Pami 1993; Sava-Vardar Zone of Pami 2002). The Sava Zone defines the LateCretaceous to Palaeogene suture between Tisza and the Dina-rides. Between Zagreb and Belgrade this Sava Zone connects

the SE branch of the Alpine Tethys with the Cretaceous-agebranches of Neotethys further to the southeast (Fig. 2c). Atpresent the Sava Zone, located between the Western and East-ern Vardar Ophiolitic Units (see Plate 1), represents the suturebetween the Dinarides and the Tisza-Dacia Mega-Units. Thelatter are derived from older branches of Neotethys.

The narrow, possibly only partly oceanic Ceahlau-Severinrift opened during Middle to Late Jurassic times (e.g.tefnescu1995; Fig. 2b). Hence it is considered as the easternmost branchof the Alpine Tethys rather than a branch of Neotethys. Note,however, that in present-day map view (Plate 1) it does notdirectly connect with the easternmost branch of the AlpineTethys of the Western Carpathians in Northern Romania andadjacent Ukraine, nor does it link up with the Transylvanianbranch of the Eastern Vardar Ophiolitic Unit. Westward, unitsattributed to the narrow Ceahlau-Severin Ocean join the Ma-gura Flysch Unit (Plate 1) that in Miocene times was thrust to-wards the SE (Fig. 3; Tischler et al. 2007) and that connects withthe Mid-Hungarian Fault Zone (see above). Southward, theCeahlau-Severin Ophiolitic Unit, which is well exposed in theSouth Carpathians, eventually appears to wedge out in west-ern Bulgaria and eastern Serbia; no equivalents of this narrow

ocean have been ascertained in the Balkan Orogen. Figure 2bdepicts two additional eastern branches of the Alpine Tethys,which are proposed to kinematically connect with the Trias-sic Neotethys Ocean and whose opening led to the separationof the Dacia and Tisza blocks from Europe. The relics of thebranch between the Dacia and Tisza Mega-Units (Fig. 2b) willform the suture between the Dacia and Tisza Mega-Units inEarly Cretaceous times, only preserved in the subsurface (seePlate 3, Profile 3). The branch between the Tisza and ALCAPAMega-Units (Fig. 2b) forms part of the Mid-Hungarian FaultZone (Fig. 1, Plate 1), i.e. the ophiolite-bearing Intrapanno-nian belt of Channell et al. (1979).

In the Alpine-Carpathian-Dinaridic system of orogensthe westernmost branch of Neotethys (Fig. 2a) is known asthe Meliata Ocean (Kozur 1991) that had opened earlier, i.e.in Triassic times (e.g. Velledits 2006). However, in our area,the ophiolitic remnants of the Meliata-Maliac Ocean do notform coherent thrust sheets, but are only preserved as blockscontained in Mid to Late Jurassic-age ophiolitic mlange for-mations. Such mlange formations occur in the Eastern Alps

and West Carpathians (Kozur & Mostler 1991). Remnants ofthis same Meliata-Maliac Ocean are also found as blocks inJurassic mlange formations that immediately underlie theobducted Western Vardar ophiolites in the Bkk Mountains(Monosbel nappe of Csontos 1999, 2000) and in the Dinarides(ophiolitic mlange formations; e.g. Babi et al. 2002). In theDinarides these mlange formations are also referred to asDiabas-Hornstein (Kossmat 1924), Diabase-RadiolariteFormation (iri & Karamata 1960) or wildflysch with ophi-olitic detritus (Laubscher & Bernoulli 1977). Note that all ob-ducted ophiolitic thrust sheets, which overlie these ophioliticmlange formations, as seen in the Bkk Mountains (Darno-Szavarsk ophiolites; Csontos 2000) and Dinarides (Western

Vardar Ophiolitic Unit; e.g. Pami et al. 1998; Dimitrijevi 2001;Karamata 2006), consist of Jurassic age ophiolites. We suggestthat these Jurassic Western Vardar ophiolites, together with theTriassic Meliata-Maliac ophiolites, once formed part of one andthe same Neotethyan oceanic branch before obduction began(Fig. 2b), i.e. before Mid-Jurassic times. During the latest Ju-rassic to Early Cretaceous the young (Early to Mid-Jurassic)Western Vardar Ophiolitic Unit was obducted onto the passivecontinental margin of Adria, the ophiolite mlange formationdefining the tectonic contact zone.

The Eastern Vardar Ophiolitic Unit extends into the SouthApuseni and Transylvanian ophiolite belt and represents an-other part of the Meliata-Maliac-Vardar Neotethys (Sndulescu1984) that was probably obducted onto the European Margin(Dacia Mega-Unit, Fig. 2b). Its original location with respectto that of the Western Vardar ophiolites is still enigmatic. Weemphasize that the Eastern Vardar ophiolitic belt does not ex-tend along the Sava Zone towards Zagreb. Hence, the EasternVardar Ophiolitic Unit does not form part of the Dinarides.Instead, it is now the most internal, structurally highest tectonicelement on top of the Dacia Mega-Unit. In turn this impliesthat the Eastern Vardar ophiolites cannot be linked with the


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Basemid-Miocene

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Dej-tuff fm.Eocene, fine grainedsiliciclastics

Eocene, sand dominatedsiliciclastics

Oligocene, sand dominatedsiliciclastics

Oligocene, sand dominatedsiliciclasticsOligocene, fine grainedsiliciclastics

Upper Cretaceous -Paleocene

External Pienides = Magura Flysch Neogene of the Pannonian BasinPost-tectonic sedimentary

cover of the Dacia Mega-Unit

Dacia Mega-UnitEocene

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Dacia Mega-Unit

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Ceahlau - Severin

ophiolitic unit

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post-Burdigalian sediments

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Pieniny Klippen Belt

Internal Pienides:

Botiza nappe

(Piemont-Liguria Ocean)

Eocene - Early Miocene

Late Cretaceous

Biharia Unit

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BogdanVodafaultDragosVodafaultDragosVodafault

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Borsa

Sighet

Baia Mare

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A A'

Fig. 3. Map (a) and cross-section (b) through the contact area between the ALCAPA and the Tisza-Dacia Mega-Units in Northern Romania (Maramures)after Tischler (2005) and Tischler et al. (2007). The Pienides of the Maramures area in Northern Romania form a tight arc in map view and were thrust onto theTisza-Dacia Mega-units during Miocene times.


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Alpine Tethys around the western margin of Tisza, nor do theyextend E-ward into the North Dobrogea Orogen. In the south,i.e. between Beograd and Skopje, the Neotethyan Western andEastern Vardar Ophiolitic Units parallel each other but areseparated by a narrow band of the Sava Zone that, in our view,represents a suture zone between the Dinarides and the Tisza-Dacia Mega-Units which, in the Late Cretaceous, included theirearlier obducted ophiolite sheets (Plate 1).

We conclude (1) that none of the branches of the Alpine Te-thys and of Neotethys extends eastward into the North Dobro-gea Orogen, although such connections have been proposed bymany paleogeographic reconstructions (e.g. Stampfli & Borel2004). The Triassic North Dobrogea rift (i.e. the Niculitel Zone;Savu et al. 1977; Seghedi 2001), which formed during a Permo-Triassic rifting event that affected also central Moesia, dies outrather rapidly northwestward (see review by Tari et al. 1997).We propose (2) that the ophiolitic remnants of Neotethys (theTriassic-age Meliata-Maliac ophiolites and the Jurassic-age Var-dar ophiolites) occurring in the area of consideration formedpart of one and the same Meliata-Maliac-Vardar oceanic basin.

We will show later that there is no evidence for the existence ofa Pindos Ocean and thereby accept the one-ocean hypoth-esis first formulated by Bernoulli & Laubscher (1972). We areconvinced (3), that the different branches of Tethys found inthe Alpine-Carpathian-Dinaridic system can only be followedeastward via the Dinarides and Hellenides into Turkey, but notinto the Cimmerian system of the Black Sea to the north.

4. Detailed description of individual tectonic units of the Alps,

Carpathians and Dinarides

This section provides the most important sources used for de-fining tectonic units and constructing the map (Plate 1). More-

over, a more detailed overview of all the tectonic units is pre-sented and supported by a series of crustal-scale cross-sections(Plates 2 & 3). Names of tectonic units listed in the legend ofPlate 1 are given in bold letters. The Alps will not be treated indetail (see Schmid et al. 2004a for a comprehensive review).We provide a relatively more comprehensive overview of theDinarides since they are the least known part of the system.

4.1. The Miocene fold-and-thrust belt of the Alps and

Carpathians

The Cretaceous and Cenozoic flysch units of the external Car-pathian fold-and-thrust belt underwent most, though probablynot all their total shortening during Miocene times. Deforma-tion progressively migrated towards the foreland (Sndulescuet al. 1981a,b; Roca et al. 1995; Morley 1996; Zweigel et al. 1998;Matenco & Bertotti 2000).

The Neogene evolution of this flysch belt was mainly drivenby the retreat of the Alpine Tethys subduction slab into theCarpathian embayment (Royden 1988). Prior to the Late Cre-taceous onset of subduction, this embayment was occupied byLate Jurassic to Early Cretaceous oceanic lithosphere of the

Alpine Tethys that was attached to the European continent(Balla 1987; Fig. 2c). Subduction of this oceanic lithospherestarted from the Late Aptian to Albian onwards. Its coveringLate Jurassic Early Cretaceous sediments were scraped off,forming the Ceahlau/Severin nappe that was emplaced about75 Ma ago (Laramide emplacement of the Ceahlau-SeverinOphiolitic Unit; e.g. Sndulescu et al. 1981a,b). There are severalpopular models such as slab detachment (e.g. Wortel & Spak-man 2000; Sperner et al. 2005; Weidle et al. 2005), slab delami-nation (e.g. Girbacea & Frisch 1998; Gvirtzman 2002; Knappet al. 2005), or thermal re-equilibration of the lithosphere (e.g.Cloetingh et al. 2004) that have been proposed to explain theevolution of this subduction and its present-day expression as anear vertical high velocity mantle anisotropy beneath Vrancia(e.g. Martin et al. 2006). Whatever model is adopted, all of theminvoke a Miocene retreat of the subducted oceanic slab as theprincipal driving force for the final emplacement of the conti-nental ALCAPA and Tisza-Dacia Mega-Units that occupy theinternal parts of the Carpathian loop.

The Carpathian thrust belt consists mainly of flysch units

in its inner part and grades outward into progressively moreshallow-water strata, the most frontal thrusts involving the in-ner parts of the Carpathian foredeep. The most internal thrustswere emplaced in Late Cretaceous time whereas the externalthrusts are of Neogene age. The age of the youngest thrust de-formation at the front of this fold-and-thrust belt decreasesfrom the West Carpathians (ca. 18 Ma) towards the Polish andUkrainian Carpathians where the latest movements are datedas Late Miocene (ca. 12 Ma; Krzywiec 2001). Further to the SEand S along the entire East Carpathians to the bending zonenorth of Bucharest the age of the youngest thrusts remainsconstant at around 11 Ma, though the amount of shorteningaccomplished across them increases significantly in the Roma-

nian segment (Roure et al. 1993; Dicea 1995; Matenco & Ber-totti 2000; Krzwiec 2001). This was partly accommodated in theinternal parts of the Carpathians by coeval late-stage sinistralstrike-slip motion along the contact between ALCAPA andTisza-Dacia (e.g. Tischler et al. 2007). The external flysch beltin the East Carpathians is completely allochthonous and con-tains sediments formerly deposited on continental or oceaniccrust of the Carpathian embayment. However, these sediments,which are incorporated in the Miocene-age nappe sequence,do not contain any detritus from an oceanic basement (e.g.Sndulescu 1988). Hence the hypothesis that parts of the Car-pathian embayment were underlain by oceanic crust (e.g. Balla1987) remains speculative.

The external Carpathian fold-and-thrust belt consists ofthree nappes or thrust systems, some of which can be traced allthe way along strike. These nappe systems are best developedin the East Carpathians where they are referred to as the Mol-davides (Sndulescu 1994).

The external-most tectonic unit consisting of Middle Eo-cene to Late Miocene sediments, the thrusted internal fore-deep, is called Subcarpathian nappe in the East Carpathians(Sndulescu 1981a,b; Dicea 1995). This unit, which is thrust over


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the undeformed sediments of the Carpathians foreland, i.e. theexternal foredeep (Plate 3, Profile 3), can be traced north alongstrike into Ukraine where it wedges out between external fore-deep and more internal thrust sheets (e.g. Kov et al. 1999;Oszczypko 2006). In the foreland of the Romanian Carpath-ian bend zone and the South Carpathians this unit is partlyburied beneath the latest Miocene-Pliocene (post-11 Ma), es-sentially undeformed sediments of the Dacic Basin (e.g. Jipa2006) (Plate 2, Profile 4). The depocenter of these sedimentsis located near the town of Focsani (Focsani Depression;Trpoanc et al. 2003).

The Cenozoic Dacic basin forms the western branch of thelarger and endemic Eastern Paratethys basin that was isolatedfrom the Mediterranean and World Ocean since the beginningof the Oligocene in response to orogenic uplift of the Alpine-Carpathian-Tauride Caucasus domains (e.g. Rgl 1999). Partsof the Dacic basin, located between the Intramoesian and Tro-tus/Peceneaga-Camena Faults, were inverted during the Qua-ternary by folds and reverse faults involving the lower plate ofthe Eastern Carpathian thrust system; this led to the develop-

ment of the synclinal configuration of the Focsani Depression(Plate 3, Profile 3; see also Leever et al. 2006).In the South Carpathians foreland, the most internal and

deformed part of the foredeep is referred to as Getic Depres-sion. Although its latest Cretaceous to Late Miocene sedimentsare buried beneath the post-tectonic cover of the Dacic basin,subsurface data show that these were thrust over the Moesianforeland (Mota & Tomescu 1983; Sndulescu 1988) (Plate 2,Profile 4). During the progressive N-, NE-, E- and ESE-wardtransport of the Tisza-Dacia Mega-Units around Moesia, theGetic Depression was dominated by dextral strike-slip displace-ments. However, the total amount of Cenozoic shortening inthe East Carpathians (


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age of the term ALCAPA by previous authors, we exclude theBkk Mountains from this Mega-Unit. The principal reasonis that the Bkk Mountains can nowadays be considered as apiece of the Dinarides (Kovcs et al. 2000, 2004; Dimitrijeviet al. 2003; Velledits 2006) rather than part of the Alpine-WestCarpathian chain. The Bkk Mountains were displaced withinthe Mid-Hungarian Fault Zone (Tischler et al. 2007), a broaderfault zone that is delimited to the south by the Mid-Hungar-ian Line (Csontos & Nagymarosy 1998), or Zagreb-ZemplinLine (Haas et al. 2000), and to the north by the eastern con-tinuation of the Balaton Line. Consequently, we let the south-ern boundary of ALCAPA coincide with the southern part ofthe Darno Line and further eastwards with the Nekseny Fault(Haas 2001; see Fig. 1). These fault zones separate the BkkMountains from two inselbergs that we consider as part of theInner West Carpathians (Uppony and Szendr Mountains ofNW Hungary; see Haas 2001, his Figs. 78 & 106). The easterntip of ALCAPA extends into Northern Romania where it wasidentified from subsurface and field data (Sndulescu et al.1978, 1993; Kov et al. 1995; Tischler et al. 2007).

4.2.2. Europe-derived units within ALCAPA

In Plate 1, and regarding the Alps, we grouped the Helveticand Ultrahelvetic cover nappes including the External Mas-sifs (Helvetic) together with the Subpenninic nappes. Theterm Subpenninic denotes pre-Mesozoic basement units, onwhich the sediments now exposed in the Helvetic and Ultra-helvetic nappes were originally deposited, as well as moredistal parts of the European upper crust, and its metamorphiccover, as exposed in the Tauern window (Schmid et al. 2004a;see Fig. 1). The most internal Europe-derived nappes arepaleogeographically assigned to the Brianonnais, a crustal

block that was detached from the European passive marginduring the Early Cretaceous opening of the Valais branch ofthe Alpine Tethys (Fig. 2c; Frisch 1979; Stampfli 1993). Theeasternmost Brianonnais nappes are exposed in the Enga-dine window (Fig. 1).

However, according to our interpretation Subpenninic unitsextend in the subsurface much further to the east. For instanceSubpenninic units, referred to as Penninic in the crustal-scaleprofile across the easternmost Alps by Tari (1996), are neededto fill the space between the base of ophiolitic nappes attributedto the Alpine Tethys (as exposed nearby in the Rechnitz win-dow) and the Moho (Plate 2, Profile 1). However, we suspectthe presence of such Subpenninic units in the subsurface alsofurther to the east, namely in the West Carpathians (Plate 2,Profiles 1 & 2). Information on the deep structure of the WestCarpathians is provided by a seismic transect presented byTomek (1993) who assigned a large rock volume below theAlpine Tethys suture (Vahicum; Plaienka 1995a,b) to the Bri-anonnais. Yet, as the Brianonnais paleogeographic domainproper terminates west of the Tauern window (Schmid et al.2004a), except for some small analogous crustal slivers found inthe Pieniny Klippen Belt of the West Carpathians (Birkenmajer

1986; Trmpy 1988), we prefer to attribute this rock volume tothe distal European margin, that is, to the Subpenninic units.

A direct comparison of the profiles across the Eastern Alpsand West Carpathians (Plate 2, Profiles 1 & 2) highlights animportant difference pertaining to the northern boundary ofALCAPA, which is only evident in cross sections. In the profileacross the easternmost Alps (Plate 2, Profile 1) the basementof the undeformed European foreland is traced along a gentlyinclined thrust at the base of the Alpine accretionary wedge farto the south into the area of the Hungarian Plain (Tari 1996).By contrast, the profile through the West Carpathians (Plate 2,Profile 2) depicts a steeply dipping dextral strike-slip zone inthe depth projection of the Pieniny Klippen Belt according toour interpretation. This crustal-scale sinistral strike-slip faultzone was active during the Miocene and formed the northernboundary of the ALCAPA Mega-Unit (Central and Inner WestCarpathians) during its eastward escape (i.e. Nemok 1993;Sperner et al. 2002). It thus post-dates nappe emplacement inthe Inner West Carpathians. The northern parts of Profile 2(Plate 2) suggest that the European foreland crust was imbri-

cated (modified after Roca et al. 1995) during the transpres-sional emplacement of ALCAPA and the development of theMiocene West Carpathian fold-and-thrust belt. In this processthe Outer West Carpathian Magura Flysch Unit was imbricatedand accreted to ALCAPA whilst severe late-stage MioceneNNE-SSW-directed back-thrusts affected the more internalunits in the High Tatra Mountains (Plate 2, Profile 2) (Sperneret al. 2002).

4.2.3. Remnants of the Alpine Tethys in ALCAPA

Most authors accept the existence of two branches of the Al-pine Tethys, thePiemont-Liguria and Valais Oceans, respec-

tively. However, this division can only be made where remnantsof the intervening Brianonnais micro-continent are present.This is no longer possible east of the Engadine window. Hence,at first sight a paleogeographic separation of the Alpine Tethysinto two separate branches (Froitzheim et al. 1996; Schmid etal. 2004a) becomes redundant in the Eastern Alps (see discus-sion in Kurz 2005 and Schmid et al. 2005) where these branchesapparently merged into one single oceanic basin. Nevertheless,we make a distinction between the eastern equivalents of thesetwo branches since an evaluation of the timing of accretion ofthese oceanic units (Late Cretaceous vs. Cenozoic) to the Aus-troalpine, respectively to the West Carpathian Tatric-Veporic-Gemeric upper plate, is an important criterion for distinguish-ing between the equivalents of the two branches of the AlpineTethys east of the Engadine window (for additional criteria seediscussion in Schmid et al. 2005). Consequently, we correlatethe Valais Ocean with theRhenodanubian Flysch since accre-tion of both units the to the Alpine nappe sequence occurredin Eocene times. The lateral equivalent even further east and inthe West Carpathians is the Magura Flysch accreted to the Tat-ric-Veporic-Gemeric orogenic wedge during Late Oligocene toMiocene times.


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ThePieniny Klippen Belt(Birkenmajer 1986) was mappedseparately (Plate 1) because it represents a rather peculiar, sub-vertical and narrow structural unit at the surface (Plate 2, Pro-file 2). It forms the boundary between Outer and Central WestCarpathians for some 700 km from the St. Veit Klippen nearVienna to northern Romania. This belt typically consists of rel-atively erosion-resistant non-metamorphic blocks of Mesozoicstrata of many different facies surrounded by less competentLate Cretaceous to Palaeogene marlstones and flysch. Onlysmall parts of this belt, that were derived from the pelagic Ky-suca-Pieniny Basin, hint to the former presence of a now com-pletely subducted eastern continuation of the Piemont-LiguriaOcean, referred to in the West Carpathians as the VahicOcean(Plaienka 1995a, 2003). Southward subduction of the Vahicoceanic crust started in the Senonian (Plaienka 1995a,b). Thisocean was located south of sedimentary rocks assigned to theCzorsztyn Ridge, the second major constituent of the PieninyKlippen Belt that probably represents an eastern equivalentof the Brianonnais continental block (Birkenmajer 1986). Itis important to emphasize that pebbles of Jurassic-age blue-

schists, thought to be derived from the Pieniny Klippen Belt(Dal Piaz et al. 1995), were not encountered in primary depos-its, but were found as recycled components in the Gosau-typesediments of the Klape Unit (Periklippen Zone; Ivan et al.2006). This unit is not considered as forming part of the PieninyKlippen Belt s.str., but as a displaced fragment of the CentralWest Carpathians (Plaienka 1995b). Hence these blueschistpebbles more likely originated from the Meliata-Maliac oce-anic domain which crops out further to the south in the Centraland Inner West Carpathians (see below) and which is not partof the Alpine Tethys.

In contrast to the Alps, in which ophiolitic nappes derivedfrom the Piemont-Liguria Ocean are well exposed (Schmid et

al. 2004a), remnants of the Vahicum that represents the easternextension of the latter do not outcrop, except for very small tec-tonic windows some 10 km south of the Pieniny Klippen Belt(Belice Unit exposed in the Povask Inovec Mountains; seePlaienka 1995a,b for details). Based on seismic data (Tomek1993), we suspect, however, that in the Central West Carpath-ians remnants of the Vahicum separate the Tatricum from sus-pected Subpenninic elements at depth (Plate 2, Profile 2). InEastern Slovakia and Ukraine boreholes have reached, in thesubsurface of the East Slovak basin, the Iaovce-KriscevoUnit that includes some serpentinite bodies (Sotk et al. l993,l994, 2000) (Fig. 1). These rocks are along strike with the Vahi-cum and hence we regard them as equivalents of the Piemont-Liguria Ocean.

The easternmost occurrences of the Pieniny Klippen Belt(Kysuca-Pieniny-type sediments) form part of the so-called Pi-enides of the Maramures area in Northern Romania (PoianaBotizei locality; Sndulescu et al. 1979/1980; Bombit & Savu1986). In map view they form a tight arc (Plate 1, Fig. 3). Theseeasternmost Pieniny Klippen Belt lithologies are a key-ele-ment for understanding the relationship between West andEast Carpathians (Sndulescu et al. 1981a, 1993; Tischler at

al. 2007). This is because they separate, within the Pienides,the more internal Botiza nappe, a lateral equivalent of theIaovce-Kriscevo Unit of Eastern Slovakia and Ukraine thatis attributed to the Piemont-Liguria Ocean, from the eastern-most equivalents of the Magura Flysch (Wildflysch nappe ofthe External Pienides, see Fig. 3). The Pienides, including boththese oceanic units and the Pieniny Klippen Belt in betweenthem, were thrust SE-ward during the Early Burdigalian overthe Dacia Mega-Unit, including its post-tectonic Late Cre-taceous to Cenozoic cover. Later they were dissected by theBogdan-Dragos-Voda fault system (Tischler et al. 2007). Assuch, the Pienides define the easternmost tip of ALCAPA thatis thrust over the Tisza-Dacia Mega-Units (Fig. 3; see Tischler2005; Tischler et al. 2007; Mrton et al. 2007). This thrusting waskinematically linked to movements along the Mid-Hungarianfault zone during the lateral extrusion of ALCAPA. The ge-ometry of the tight Pienides arc in northern Romania led usto correlate the Botiza nappe, which we consider as the lateralequivalent of the Piemont-Liguria branch of the Alpine Tethys,with the Szolnok Flysch that occurs in the subsurface of the

Pannonian Basin in eastern Hungary near Debrecen (Plate 1).Furthermore, we propose to connect this Szolnok flysch belt,which forms part of the Mid-Hungarian Fault Zone (or theophiolitic Intrapannonian Belt in the sense of Channell et al.1979) with the westernmost parts of the ophiolite-bearing SavaZone of the Dinarides near Zagreb. According to our interpre-tation, Miocene dextral movements within the Mid-HungarianFault Zone (Zagreb-Zemplin line; Haas et al. 2000) disruptedthe original connection between the Sava Zone of Croatia andnorthern Bosnia and the Pienides of northern Romania.

4.2.4. Adria-derived nappes in ALCAPA and remnants of the

Triassic Meliata-Maliac OceanThe compilation of Adria-derived units, known as the Aus-troalpine nappes in the Alps, follows the scheme proposed bySchmid et al. (2004a), except for minor modifications in theeasternmost Alps that are discussed below. Correlation of theseAlpine units across the Vienna Basin and the Little Hungar-ian Plain with the equivalent ones in the West Carpathians isbased on compilations of subsurface (seismic and/or borehole)data provided by Flp & Dank (1967), Flp et al. (1987), Tari(1994, 1996), Plaienka et al. (1997a), Tari et al. (1999), Haas etal. (2000), and Haas (2001).

TheLower Austroalpine nappes representing the structur-ally lowermost units of the Austroalpine nappe sequence werederived from the northern passive margin of Adria that facedthe Piemont-Liguria Ocean. At the eastern margin of the Alps,the subdivision proposed by Schmid et al. (2004a) was slightlymodified: the Semmering nappe, without the overlying nappesthat are built up by the so-called Grobgneiss Unit and the Stral-legg Complex (Schuster et al. 2001, 2004), was included intothe Lower Austroalpine nappe pile. This permits a correlationof the Lower Austroalpine units with an equivalent nappe se-quence of the West Carpathians known as the Tatricum (i.e.


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Plaienka et al. 1997a). Very probably the rocks in the LeithaMountains of the easternmost Alps SE of Vienna extend east-ward into the Hainburg Hills and the Mal Karpaty Mts. of theWest Carpathians near Bratislava (Plaienka et al. 1991). Struc-turally, the Tatricum represents the lowermost Adria-derivednappe that consists of Variscan basement and its sedimentarycover and that was derived from a position adjacent to the Va-hic (= Piemont-Liguria) Ocean (Dumont et al. 1996; Plaienkaet al., 1997a). As revealed by deep seismic transects, the Tatri-cum forms a tabular, upwards slightly convex and more than10 km thick thrust sheet (Plate 2, Profile 2) that extends intothe lower crust below the Veporic units (Tomek 1993; Bieliket al. 2004).

Subdivision of the Upper Austroalpine nappe system andits West Carpathian equivalents into northern margin of Me-liata, Eoalpine high-pressure belt and southern margin of Me-

liata units, as proposed in our compilation (Plate 1), followsessentially the new subdivision of the Upper Austroalpine unitsof the Alps as proposed by Schuster et al. (2004) and Schmid etal. (2004a). Note, however, that this concept, as briefly outlined

below, applies strictly only to the West Carpathians and the east-ern parts of the Eastern Alps since the oceanic Meliata-Maliacembayment did not extend into the Austroalpine domain of themore western areas. This applies also to the related Eoalpinehigh-pressure belt, the westernmost parts of which are presentin the southern tztal basement (Schmid et al. 2004a).

This new subdivision is supported by the following dataand/or concepts:

(1) The sedimentary nappes of the Northern CalcareousAlps were derived from the northern passive margin of the Tri-assic Meliata Ocean that formed a branch of the Neotethys. The

most distal parts of this margin are characterized by the classicalHallstatt facies (e.g. Mandl 2000; Gawlick & Frisch 2003). Wedo not share the view of Neubauer et al. (2000) who proposedthat within the domain of the present-day Northern CalcareousAlps a Meliata suture separates two conjugate passive mar-gins. Instead, we interpret the stratigraphic evidence for LateJurassic compressional tectonics in the Northern CalcareousAlps (Gawlick & Frisch 2003; Gawlick & Schlagintweit 2006)to be related to the development of an accretionary wedge atthe front of an obducted Jurassic-age ophiolite body (VardarOcean). This obduction event followed an earlier pulse of intra-oceanic subduction (see chapter Dinarides) during which theTriassic parts of the Neotethyan oceanic lithosphere, namelythe Meliata Ocean, were consumed.

(2) After this obduction event, major deformations accom-panied by the stacking of the Austroalpine nappe units startedduring the Late Valanginian (ca. 135 Ma). This is indicated bythe development of the syn-orogenic Rossfeld sedimentary ba-sin in the Northern Calcareous Alps (Faupl & Wagreich 2000)in the Northern Calcareous Alps. It is this shortening, referredto as the Eo-Alpine tectono-metamorphic event, that we relate

to the final closure of the westernmost parts of the Neotethysoceanic realm. A SE- to E-dipping subduction zone developedwithin and/or near the western termination of the Neotethysoceanic embayment into Adria (Fig. 2), possibly along a Juras-sic strike-slip fault (see discussions in Schuster & Frank 1999;Frank & Schlager 2006). In the Alps and along this intra-conti-nental subduction zone located at the western end of the Meli-ata Ocean, crustal rocks were transported to great depths some90 Ma ago (Thni 2006).

(3) The intra-continental, partly eclogitic, former subduc-tion zone, referred to asEoalpine high-pressure beltin Plate 1,subdivides the Upper Austroalpine basement nappe sequenceinto two parts (Schmid et al. 2004a): the Silvretta-Seckau nappesystem in its footwall (northern margin of Meliata in Plate 1,together with the Northern Calcareous Alps and the Grau-wackenzone) and the tztal-Bundschuh and Drauzug-Gurktalnappe systems in its hanging-wall (part of thesouthern marginof Meliata in Plate 1, together with the Southern Alps).

Correlation of the Upper Austroalpine units of the Alps with

the major tectonic units of the West Carpathians (Plate 1) hasto contend with considerable difficulties, since major changesoccur along strike in the architecture of the Cretaceous-age(Eoalpine) orogen. Hence, individual Upper Austroalpineunits cannot be cylindrically traced eastwards. The absence ofexposed Eoalpine high-pressure rocks east of the Alps, possi-bly due to their burial beneath the fill of the Pannonian Basin,presents an additional difficulty.

We correlate the Drauzug-Gurktal nappe system with theTransdanubian ranges since we interpret both of these units tostructurally represent the hanging-wall with respect to the Eo-alpine high-pressure belt. Therefore Drauzug-Gurktal nappesystem and Transdanubian ranges paleogeographically rep-

resent realms along the southern margin of the Meliata-Ma-liac Ocean. The Transdanubian ranges are made up of weaklymetamorphosed Variscan basement that is overlain by a non-metamorphic Permo-Mesozoic cover. This cover exhibits closesimilarities to the Drauzug and the Southern Alps (e.g. Kazmer& Kovcs 1985; Haas et al. 1995). This correlation is also war-ranted on structural grounds; the Transdanubian ranges arelocated immediately N of the Balaton Line, the eastern ex-tension of the Periadriatic Line, along which the Austroalpineunits (Drauzug and Transdanubian ranges) escaped to the east(Kazmer & Kovcs 1985). Hence, the Drauzug-Gurktal nappesystem and the Transdanubian Ranges are interpreted as al-lochthonous tectonic units that structurally overlie the postu-lated eastern extension of the Eoalpine high-pressure units(Plate 2, Profile 1).

Conversely we correlated all units of the Central and In-ner West Carpathians with the Silvretta-Seckau nappe system,the Northern Calcareous Alps and the Grauwackenzone. Wepropose that the easternmost parts of these units were de-rived from the northern margin of the Meliata-Maliac Ocean.These units form the lower plate with respect to the Eoalpinehigh-pressure belt of the Alps and include the thick-skinned


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Veporicum and Gemericum thrust sheets, as well as a seriesof detached sedimentary nappes. From external to internal,the latter are referred to as Fatricum, Hronicum and Silicicumunits (Plaienka 1997a; see Plate 2, Profile 2). According to ourinterpretation this group also includes rock associations thatcrop out in isolated inselbergs, the Uppony, Szendr and Zem-plin mountains (Fig. 1), whose assignment to specific units ismuch debated. These inselbergs are located to the northwestand north of the southern boundary of ALCAPA, marked bythe Darno and Nekszeny Faults (Fig. 1).

The structural and paleogeographic relationships betweenthe most internal and structurally highest system of cover nappes(Silicicum in Slovakia or Aggtelek-Rudabnya Unit in Hun-gary; Haas 2001) and the Meliaticum are still enigmatic. Oneschool of thought considers the Meliaticum as a suture zone,referred to as Roava suture (i.e. Plaienka et al. 1997a,b). Inthis case, however, the Silicicum, together with a weakly meta-morphic cover slice at its base referred to as Tornaicum (Mar-tonyi in Hungary; see Fodor & Koroknai 2000; Less 2000) or asSouth Rudabnyaicum (Kozur & Mock 1997), would represent

the upper plate with respect to this suture as they overlie theMeliaticum. Hence, these units (Inner West Carpathians ofPlaienka 1997a) would, contrary to our interpretation (Plate 1and Plate 2, Profile 2), represent the southern margin of theMeliata-Maliac Ocean.

We chose another option. According to our interpreta-tion the Silicicum-Aggtelek Unit was derived from the north-ern passive continental margin of the Triassic Meliata-MaliacOcean, with the Bodva sub-unit in northern Hungary (e.g.Kovcs 1992; Kovcs et al. 1997) representing its southernmostand most distal parts (Fig. 4a). The paleogeographic positionof the Silicicum-Aggtelek Unit is very reminiscent of that ofthe Juvavic nappes of the Northern Calcareous Alps (Fig. 4a).

Due to the development of a triangle structure formed duringLate Jurassic obduction of the West Vardar Ophiolitic Unit, apart of the northern distal passive margin of the Meliata-Ma-liac Ocean (Silicicum-Aggtelek unit) now tectonically overliesophiolitic mlange with remnants of the Meliata-Maliac Ocean(Fig. 4b, right). Hence, for the Western Carpathians we proposethat S-directed back thrusting, associated with the formationof this triangle structure, is responsible for the present-day tec-tonic position of the Silica-Aggtelek cover nappes in the hang-ing-wall of obducted remnants of the Triassic Meliata-MaliacOcean (Plate 2, Profile 2; Fig. 4b, right). Our field observationssupport S-directed Jurassic thrusting for the southernmost ex-posures of the West Carpathians in Northern Hungary. Sub-sequent Cretaceous deformation was N-directed (Balla 1987),with in-sequence thrusting gradually propagating northward(Fig. 4c, right; Plaienka 1997a,b).

Consequently, we place the suture of the Meliata-MaliacOcean further to the south, namely between the southernmostexposures of the Central and Inner West Carpathians of theUppony Mountains in the north and the Bkk Mountains tothe south. The latter represent a displaced part of the Dina-rides. This suture formed during the Early Cretaceous and was

severely overprinted by Cenozoic strike-slip faulting along theDarno Line during the lateral eastward extrusion of the Alpsand Dinaridic fragments (Plate 1 and Plate 2, Profile 2).

A geometrically similar situation is found in the eastern-most Alps (Mandl & Ondrejickova 1991; Kozur & Mostler1991; Neubauer et al. 2000; Frank & Schlager 2006). In spiteof the great similarities between the nappe units of the WestCarpathians and the Eastern Alps (Fig. 4), we prefer a differentscenario for the Northern Calcareous Alps, largely followingMandl (2000) and Frank & Schlager (2006). In this interpreta-tion Late Jurassic/Early Cretaceous emplacement of the mostdistal elements, the so-called Tiefjuvavikum including Meli-ata-type ophiolitic mlanges (Fig. 4b, left), was followed by out-of-sequence Cretaceous imbrication of the Hochjuvavikum(Fig. 4c, left).

The Meliata Unit of the West Carpathians and easternmostEastern Alps includes different elements that do not repre-sent ophiolitic bodies in a strict sense. The Meliaticum of theWest Carpathians consists of two units: (1) the metamorphosedBrka Unit, that was derived from near the ocean-continent

transition of the northern margin of the Meliata-Maliac Oceanand which underwent low-temperature, high-pressure (12 kbar)metamorphism (Faryad 1995a & b, 1997; Mello et al. 1998), and(2) the Meliata Unit s.str. (Mock et al. 1998), a non-metamor-phic ophiolite-bearing mlange which forms part of a Jurassicaccretionary flysch complex containing radiolarites, olistos-tromes, mlanges and ophiolitic bodies (Kozur & Mock 1997).Glaucophane-bearing basalts from the base of the Meliata ac-cretionary complex (Brka Unit) overriding the southernmostGemericum yield Middle to Late Jurassic ages (150160 Ma)for their HP-LT metamorphism (Maluski et al. 1993; Dallmeyeret al. 1996; Faryad & Henjes-Kunst 1997). This demonstratesthat Mid-Jurassic intra-oceanic subduction processes preceded

latest Jurassic obduction onto the distal northern continentalmargin of the Meliata-Maliac Ocean that was associated withthe development of an accretionary wedge. This subductionclearly pre-dated, and is hence not related to the Late Valangin-ian onset of nappe stacking in the Eastern Alps (Gawlick &Frisch 2003) and West Carpathians.

We can only speculate that the Eoalpine high-pressure beltof the Eastern Alps, which represents a Cretaceous-age partlyintra-continental suture that post-dates obduction of the Me-liaticum onto the Juvavic and Gemeric units of the Alps andWest Carpathians, respectively, might also be present in thesubsurface of the Pannonian plain. We suggest its presencealong a geophysically defined belt of linear deep-seated faultsconsisting of the Raba and Hurbanovo-Disjen faults (Fig. 1),based on data from Plaienka et al. (1997a; their Fig. 2). ThisCretaceous-age suture (Eoalpine high-pressure belt of Plate 1)would coincide with the northern limit of the TransdanubianRange Unit along the Disjen Fault, as proposed by Haas(2001). Borehole data analysed by Koroknai et al. (2001), re-vealed immediately north of the Disjen Line the occurrenceof basement that is characterized by Eo-Alpine amphibolite-grade metamorphism, typical for the Veporic Unit of the West


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Carpathians. Moreover, these data indicate that this high-pres-sure belt probably wedges out eastward (Plate 1). In addition,these findings provide further evidence for the existence of animportant tectonic boundary that separates the non-metamor-phic Transdanubian Ranges, derived from south of the Meli-ata-Maliac Ocean, from the Veporic Unit of the Central WestCarpathians that we place to the north of the Meliata oceanicembayment.

4.3. East Carpathians, South Carpathians, Transylvanian Basinand Carpatho- Balkanides (Danubian nappes and Dacia)

4.3.1. Overview

The internal tectonic units of the East and South Carpathians,which are fringed to the E and S by the external Miocene thrustbelt, were emplaced in Cretaceous time (i.e. Sndulescu 1984,1994; Krutner et al. 1988; Krutner 1996). Sndulescu (1984,1994) referred to these units as the Marginal, Outer and Me-

dian Dacides. In the Hungarian literature, the Outer and Me-dian Dacides are referred to as the Dacia Mega-Unit or terrane(i.e. Csontos & Vrs 2004), whilst Burchfiel (1980) refers tothem as the Rhodopian fragment.

The Danubian nappes, also referred to as Marginal Dacides,however, were originally part of the Moesian foreland. TheOuter and Median Dacides of the Dacia Mega-Unit, togetherwith more internal units located below the Transylvanian Basinand cropping out in the North Apuseni Mountains (Tisza Mega-Unit; e.g. Haas & Pero 2004, referred to as Internal Dacides bySndulescu 1984), moved into the Carpathian embayment dur-ing Cenozoic times (i.e. Royden 1988; Fodor et al. 1999; Mrton2000; Wortel & Spakman 2000; Csontos & Vrs 2004; Horvthet al. 2006). These internal units were finally docked against theEuropean foreland during the Miocene, controlling the evolu-tion of the earlier described external fold-and-thrust belt thatinvolves Cretaceous to Tertiary-age flysch units.

Along the western margin of the Moesian Platform theSouth Carpathian units can be traced further southward into

MeliataBodva

Permian evaporites future intra-oceanic subduction

future thrust Silicicum over Gemericum

Torna BkkSilicicumGemericum

Tiefjuvavikum southern margin of MeliataHochjuvavikumTirolicum

W-Carpathians:

Eastern Alps:

future thrust Gemericum over Veporicum

Jurassic ophiolite bearing melange

wedging of

obducted

oceanic crust

Jurassic ophiolite bearing melange

N (present-day coordinates) S

future out-of-sequence thrust

future thrust Tirolicum

over Bajuvaricum

West Carpathians:Eastern Alps:

a)

b)

c)

Fig. 4. Conceptual model for Late Jurassic and Cretaceous thrusting affecting the former passive continental margin adjacent to the Meliata Ocean in theEastern Alps (Northern Calcareous Alps) and in the West Carpathians. a) Former passive margin of Neotethys and terminology of the various paleogeographicdomains and tectonic units as used in the West Carpathians (top line) and the Eastern Alps (bottom line). b) Late Jurassic thrusting in the Alps (left) and in the

West Carpathians (right: triangle structure). c) Overprinting during Early Cretaceous orogeny in the Alps (left) and in the West Carpathians (right).


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eastern Serbia and western Bulgaria. There they are referredto as the Carpatho-Balkanides. They also include, what Ser-bian authors refer to as the Serbo-Macedonian Massif (e.g.Dimitrijevi 1997). Some of these units can then be traced east-ward into the Balkan Orogen whilst others follow the easternrim of the Eastern Vardar Ophiolitic Unit and extend south-ward into Northern Greece (Plate 1). Two curved strike-slipfaults, the Cerna-Jiu Fault (Berza & Drgnescu 1988) andthe Timok Fault (Visarion et al. 1988; Moser 2001; Krutner& Krsti 2002, 2006), displace the Cretaceous nappe sequencealong the contact between the Dacia Mega-Unit and the Moe-sian Platform. These faults accommodated Early Oligocene toEarly Miocene dextral strike-slip motion with total displace-ments of up to 100 km (Moser 2001; Fgenschuh & Schmid2005) as Dacia was mouldered around the western tip of theMoesian Platform (Ratschbacher et al. 1993). The Timok Faultcan be traced southward and appears to be kinematically linkedto extensional deformation in the Osogovo Mountains (Kou-nov et al. 2004) and along the Strymon fault system of NorthernGreece (Dinter 1998; Kilias et al. 1999).

4.3.2. Danubian nappes

TheDanubian nappes consist of a Neoproterozoic basement(e.g. Ligeois et al. 1996; Seghedi et al. 2005), Paleozoic rocksthat were deformed during the Variscan cycle (e.g. Iancu et al.2005) and Carboniferous to Late Cretaceous cover sequences(Berza et al. 1983, 1994). This imbricated nappe sequence de-veloped by eastward thrusting during the latest Cretaceous(Late Campanian Maastrichtian; often referred to as theLaramide phase in the Romanian literature; e.g. Krutner1993; Berza et al. 1994) under low-grade (sub-greenschist tolowermost greenschist facies) metamorphic conditions (Berza

& Iancu 1994). It is best exposed in a tectonic window in theSouth Carpathians referred to as the Danubian window (e.g.Murgoci 1905). After Late Cretaceous nappe emplacementthis unit was exhumed during Late Eocene to Oligocene time(Schmid et al. 1998; Fgenschuh & Schmid 2005). The rocks inthe Danubian nappes have a Neoproterozoic (Panafrican)tectono-metamorphic evolution similar to that of the basementin the Moesian Platform (e.g. Ligeois et al. 1996; Seghedi et al.2005), a unit with Northern Gondwana paleogeographic affini-ties (Vaida et al. 2005). The Mesozoic cover of the Danubiannappes is characterized by Early Jurassic Gresten facies (e.g.Nstseanu et al. 1981), followed by Late Jurassic to Early Cre-taceous platform carbonates, Albian to Turonian deeper marinepelagic limestones and marls that give way to a Turonian andSenonian flysch sequence. Most authors regard the Danubiannappes as having been detached from the Moesian Platform, asshown in Profile 4 (Plate 2).

Following Visarion et al. (1978) and tefnescu et al. (1988)we suggest that the Danubian nappes continue northward inthe subsurface below the East Carpathians (see Plate 3, Pro-file 3) as far north as the pre-Neogene Trotus Fault (Fig. 1).Southwards the Danubian nappe sequence extends into eastern

Serbia and western Bulgaria (see Plate 1 & Plate 3, Profile 5)as indicated by the 1 : 100'000 sheets of Geological Maps offormer Yugoslavia (Osnovna Geoloka Karta SFRJ) and dataprovided by Krutner & Krsti (2002, 2006) and Cheshitev etal. (1989). In Serbia (Dimitrijevi 1997) the Danubian nappesare locally known as Miro Unit (west of the Timok fault) andVrka uka Unit (east of the Timok fault), or as Vrka uka-Miro terrane (Karamata 2006). The Vrka uka Unit extendsinto western Bulgaria, where it is known as the West BalkanUnit (Kounov 2002). However, in the Balkan Mountains north-directed Eocene age thrusting overprinted many of the olderCretaceous structures (Boyanov et al. 1989).

4.3.3. The Ceahlau-Severin Ocean

The Ceahlau nappe (including the Black Flysch and Baraoltthrust sheets) of the East Carpathiansand the equivalent ophi-olite-bearingSeverin nappe of the South Carpathians form awedge that was accreted already in mid-Cretaceous (Aptian)time to the continental units of the overlying Bucovinian-Getic

nappes (Sndulescu 1984). Ceahlau and Severin OphioliticUnits represent the relics of what we refer to as the Ceahlau-Severin Ocean.

The Ceahlau nappe of the East Carpathians is the largestand main unit derived from this ocean. The Black Flysch andBaraolt thrust sheets occupy a higher tectonic position butwere mapped as part of the Ceahlau-Severin Ophiolitic Unitin Plate 1. The Black Flysch nappe (Bleahu 1962; Sndulescu1975) exposes a basement that consists of massive basalticflows and dykes; younger basalts also intrude into the overlyingKimmeridgian-Aptian sediments. Since the mafic complex dis-plays intra-plate geochemical characteristics it is not part of anophiolitic sequence in the strict sense (Sndulescu et al. 1981a).

These rocks were possibly located at the NW margin (in pres-ent day coordinates) of the Carpathian oceanic embaymentand perhaps formed along large transtensional faults (Badescu1997). Near the southern termination of the East Carpathians,the equivalent of the Black Flysch nappe is the Baraolt nappe(tefnescu 1970). This nappe is exclusively made up of Berria-sian to Aptian sandy-calcareous turbidites. The large Ceahlaunappe consists of basal Late Jurassic radiolarites, with basicigneous rocks and other deep-water deposits (Azuga Facies),which are overlain by mostly shaly and calcareous Tithonianto Neocomian (Sinaia beds) and Barremian to Aptian proxi-mal turbidites (Comarnic Beds). Late Aptian to Albian massivesandstones and cong

Documents

The Alpine-Carpathian-Dinaridic Orogenic System Correlation And