Matenco-bertotti-2000

8/18/2019 Matenco-bertotti-2000

1/32

Tectonophysics 316 (2000) 255–286www.elsevier.com/ locate/ tecto

Tertiary tectonic evolution of the external

East Carpathians (Romania)L. Matenco a,*, G. Bertotti b

a Bucharest University, Faculty of Geology and Geophysics, 6 Traian Vuia str., sect. 1, 70139 Bucharest, Romania

b Department of Sedimentary Geology, Vrije Universiteit, De Boelelaan 1085, 1081 HV Amsterdam, Netherlands

Received 16 February 1999; accepted for publication 1 October 1999

Abstract

Paleostress calculation and analysis of mesoscopic structures are integrated with depth interpreted geological

profiles based on seismic studies and well correlation to derive a Tertiary tectonic model for the East Carpathians.Following Early Miocene and older orogenic phases, the first tectonic event that aff ected the studied area is

characterised by a WSW–ENE-oriented shortening of Middle Miocene (Late Burdigalian) in age. Resulting

deformations induced ENE-ward thrusting of Tarcau and Marginal units, as well as the internal part of the

Subcarpathian nappe. A second shortening event with an E–W to WSW–ENE contraction direction took place in the

Late Miocene (Sarmatian), characterised by further foreland thrusting of the Subcarpathian nappe and out-of-

sequence deformation in the Tarcau and Marginal Folds nappes. Along strike, diff erences in deformation mechanisms

are controlled by the friction coefficients along the main detachment layers, by the lateral variations in the wedge

thickness and by the involvement in the northern part of the thrusting system of the thick, competent East European

platform. Tear faulting occurred in both tectonic events, the main resulting structure being the triangle zone developed

south of the Trotus valley. The Latest Miocene (Latest Sarmatian)–Early Pliocene is characterised by a strike–slip

stress field with NNE–SSW compression and WNW–ESE tension axis, left-lateral faults being dominant. The last

deformation which aff ected the studied area is characterised by NNW–SSE shortening during the Pliocene, majordeformations taking place mainly in the SW-most bending zone. © 2000 Elsevier Science B.V. All rights reserved.

Keywords: East Carpathians; Tertiary; subsurface data; paleostress; tectonic model

1. Introduction 1984; Royden, 1988; Csontos, 1995) ( Fig. 1) . The

Carpathians consist of a nappe pile of crystallineThe Romanian segment of the Carpathians is a rocks with Upper Paleozoic to Mesozoic sedi-

highly arcuate orogenic belt formed in response to mentary cover and, in an external position, asubduction and continental collision between the Lower Cretaceous to Tertiary thin-skinned belt.European and Apulian plates and related micro- The Alpine tectonic evolution of the Carpathians

plates during the Alpine orogeny (Sandulescu, is traditionally subdivided into Triassic to Early

Cretaceous extension followed by Middle

Cretaceous to Pliocene shortening (e.g.* Corresponding author. Tel.:+40-1-2117390;

Sandulescu, 1984). Three main Tertiary deforma-fax:+40-1-2113120.

tional stages are recognised (Csontos, 1995 andE-mail addresses: [email protected] (L. Matenco),[email protected] (G. Bertotti) references cited therein). During Paleogene–Early

0040-1951/ 00/ $ - see front matter © 2000 Elsevier Science B.V. All rights reserved.

PII: S 0 0 4 0 - 1 9 5 1 ( 9 9 ) 0 0 2 6 1 - 9


2/32

256 L. Matenco, G. Bertotti / Tectonophysics 316 (2000) 255–286

Fig. 1. Tectonic sketch map of the Carpathians system and the location of the studied areas. 1, Central part of the East Carpathians.

2, Southern part of the East Carpathians. TF=Trotus Fault; IMF=Intramoesian Fault.

Miocene times, clockwise rotation of the Tisza– mainly concentrated in the external parts of the

junction zone between the East and SouthDacia block (Csontos, 1995), part of the

Pannonian–Carpathians system, caused NNE– Carpathians.

The evolution of the Carpathians belt is charac-SSW to ENE–WSW shortening in the internal

Moldavides nappes (Convolute flysch and terised by temporal changes of stress and strain

fields. This is shown by an increasing amount of Audia/ Macla nappes, Fig. 2). Middle and Late

Miocene (Badenian–Sarmatian) deformations led structural data (Ratschbacher et al., 1993; Fodor

et al., 1996; Huismans et al., 1997; Matenco, 1997;to E–W shortening, which caused further deforma-tion of the external East Carpathians. Late Linzer et al., 1998; Zweigel et al., 1998) and

required by the arcuate shape of the belt (e.g.Miocene to Pliocene NW–SE (to N–S) shortening

in the East Carpathians led to further deformation Csontos, 1995). Models assuming a roughly con-

Fig. 2. Schematic structural cross-section in the central part of the East Carpathians (simplified from Stefanescu and working group,

1988). Location of the section in Fig. 1.


3/32

257L. Matenco, G. Bertotti / Tectonophysics 316 (2000) 255–286

temporaneous emplacement of thrust sheets in the fold-and-thrust belt, and the Tertiary kinematicsvarious segments of the Carpathians (e.g. of the Trotus and Intramoesian fault systems.Sandulescu, 1984, 1988) are unlikely because of the absence of structures able to accommodate the

required coeval large orogen-parallel extension 2. The structure of the external East Carpathians:(e.g. Morley, 1996). Other models, envisaging the depth data analysisCarpathians as mainly due to E-ward translation

of the Intra Carpathians units (Royden, 1988; The East Carpathians are schematically madeEllouz and Roca, 1994; Linzer, 1996) are at odds up of a stack of basement nappes (internalwith structural data and with the absence of large- Dacides) with crystalline rocks and a Mesozoicscale transcurrent movements within the South sedimentary cover, tectonically overlying theCarpathians (e.g. Rabagia and Fülöp, 1994; internal (Ceahlau, Curbicortical ) and externalMatenco et al., 1997a). Most recent models (e.g. (Audia/ Macla, Tarcau, Marginal Folds) nappeRoyden, 1988; Csontos, 1995; Linzer, 1996) lack system (Sandulescu, 1984, 1988). The latter unitsa real integration between outcrop structural are thrust over the Subcarpathian nappe, which isanalysis with seismically imaged structures buried itself carried over the undeformed forelandin the foredeep (Dicea et al., 1966; Dicea, 1995, (European, Scythian and Moesian platforms)1996; Tari et al., 1997). As a result, important (Sandulescu, 1984) (Fig. 2). Thrusting respected,diff erences exist between these models, mainly con- in general, a foreland propagating sequence. The

cerning the timing and especially the motion direc- chain has a non-cylindrical shape and ages of tions through time.thrusting change along strike, possibly as a conse-

Several kinematic studies have been publishedquence of the pre-existing structural grain (Ellouz

on the South Carpathians (e.g. Ratschbacher et al.,and Roca, 1994). The total shortening of the East

1993; Matenco et al., 1997a; Schmid et al., 1998)Carpathians outer units from Late Oligocene to

and on the bend zone connecting the East andPresent is about 180 km (Ellouz et al., 1994).

South Carpathians (e.g. Morley, 1996; HyppoliteTurbiditic and other clastic units forming the

and Sandulescu, 1996). Much less is known in theexternal East Carpathians nappes (Tarcau,

East Carpathians, especially in the central areasMarginal and Subcarpathian) and their unde-

stretching from the Slovakian and Polishformed foredeep have been deposited in a roughlyCarpathians to the Vrancea bending area (Fig. 1).eastward thinning basin associated with TertiaryClassical studies on the external East Carpathians

thrusting of the Carpathians nappes. Sediments of deal with the external part of the chain and with the basin fill are mainly derived from the hinterlandthe stratigraphic evolution of the foredeep mainlybut, especially after the Eocene, sediment inputbased on surface/ outcrop studies (e.g. Joja et al.,from the external areas became significant1968; Bancila, 1958; Ionesi, 1971; Sandulescu,(Sandulescu et al., 1981b). Sediment facies and1984; Sandulescu et al., 1981a,b and referencesdepositional geometries were influenced by NW– cited therein), but generally lack good structuralSE-trending paleo-highs inherited from Latecontrol.Permian–Middle Jurassic (Ellouz and Roca, 1994)In this paper we aim to fill the gap in knowledge,and Paleogene (Sandulescu, 1992) extensionalpresenting new structural data from the segmentstructures which were inverted during Lateof the East Carpathians comprised between theJurassic–Early Cretaceous and post-Senoniannorthern Romanian border and the Intramoesianshortening episodes, respectively.fault to the south. Integrating these data with

We present the main features of the externalinterpreted seismic profiles, we reconstruct theEast Carpathians units and of their foredeep withkinematic evolution of the East Carpathianstwo regional geological maps and 14 regionalduring Tertiary times. We devote particular atten-sections based on published and unpublishedtion to less studied topics, such as the role of seismically controlled profiles numbered from I instrike–slip faulting, the relations between struc-

tures in the subducting plate and structures in the the north to XIV in the south (Figs. 3 and 4).


4/32


Fig. 3. Geological structural map of the Central East Carpathians. Compiled from Sandulescu et al. ( 1981b); geological maps

1:200,000 and 1:50,000, published by the Geological Institute of Romania and results of this study. Thick, grey lines, SI to SV,

indicate the position of the geological sections. OHW, Oituz half-window; BHW, Bistrita half-window; GHO, Gura Humorului

outlier. Location of the map is shown in Fig. 1.


5/32


Fig. 4. Simplified geological–structural map of the southern part of East Carpathians (modified after Sandulescu et al., 1981b) with

the location of the depth-interpreted profiles used in the present study. OHW, Oituz half-window; VHW, Vrancea half-window; SS,

Slanic syncline; DS, Drajna syncline; BA, Breaza anticline. Location of the map is shown in Fig. 1.


6/32



7/32


While detailed structural and stratigraphic images marls and a thin sandstone unit (Joja et al., 1968)

(Fig. 5). The Oligocene is represented by thickhave been obtained for the European platform

and for the Subcarpathian nappe, steep dips and sandstones, sandy–marly turbidites and

wildflysch/ olistolite laterally continuous with meni-lack of good seismic reflectors have made difficult

the unravelling of the deep structure of the external lites and bituminous marls, bituminous paper

shales interlayered with siliceous sandstonesnappes ( Tarcau, Marginal ). Subsurface images in

these units are mainly based on correlation ( Kliwa) (Joja et al., 1968) (Fig. 5). According to

Sandulescu et al. (1981a), these rocks were shedbetween the surface geology and the deep wells.

Consequently, the shallow levels of the sections from external zones.

The Marginal Folds nappe (Dumitrescu, 1952)are generally well constrained, while the deeper

ones are relatively uncertain. (also named External or Vrancea nappe) ( Figs. 3

and 4) can be followed discontinuously along theIn this work, the time scale used for the Middle–

Late Miocene to Pliocene deposits represents a belt. Outcrops in the studied area are limited to

the half-windows (Bistrita, Oituz, Vrancea) or tolocal combination of Central and Eastern

Paratethys regional stages. Correlation with the the ‘rabotage outliers’ (sensu Sandulescu, 1984)

(Figs. 3 and 4). From N to S, the width of theglobal Tethys stages (Rögl, 1996) is schematically

drawn in Fig. 5. Marginal unit increases up to the Trotus valley,

and then decreases southward. The unit disappears

south of the Vrancea half-window, (Figs. 3 and 4). 2.1. Stratigraphy and sedimentology of the nappes

and of the foreland Sediments of the Marginal Folds nappe aresimilar to those of the eastern part of the Tarcau

nappe (Fig. 5). Thin Lower Cretaceous toThe Tarcau (Sandulescu, 1984) or Medio-mar-

ginal (Bancila, 1955) nappe is the most internal of Paleocene black shales, variegated shales and other

pelagic rocks are found at the base of the nappethe three considered units (Figs. 3 and 4). It is

composed of Lower Cretaceous to Turonian black units (Sandulescu et al., 1981a). Fine-grained tur-

bidites with coarse intercalations are characteristicand variegated shales and marls followed by a

mainly turbiditic succession of Senonian to Late for the Paleocene to Lower Eocene and are capped

by the regionally widespread Doamna limestoneOligocene age, which becomes finer-grained from

SW to NE (Dumitrescu, 1952) (Fig. 5). Senonian ( Upper Eocene). This is followed by Globigerina

beds, sandstones, bituminous rocks of Oligoceneto Middle Eocene marls and subordinate sands

are laterally replaced by limestones and sand–shale age and by the Upper Oligocene Kliwa quartzare-nites (Sandulescu et al., 1981a; Ionesi, 1971). Thealternations. Eocene deposits change from thick,

coarse-grained sandstones (Tarcau sandstone) to youngest deposit found in the Marginal Folds

nappe is the Lower Miocene salt formation, onlyfiner-grained, often shaly turbidites in the NE.

These formations are overlain by a thin calcareous locally overlain by molasse type sediments (Hirja)

(Sandulescu et al., 1981a) (Fig. 5).limestone unit, the Doamna limestone, developed

especially east and north of the Bistrita valley, and The easternmost allochthonous unit is the

Pericarpathian (Mrazec and Popescu-Voitesti,by shaly–marly–sandy turbidites, Globigerina

Fig. 5. General time correlation table, stratigraphic column for the Tarcau, Marginal and Subcarpathian units (modified after

Sandulescu et al., 1981a) and tectonogram of the main Cretaceous–Tertiary tectonic events for the East Carpathians. Correlation

with Central and Eastern Paratethys for the Oligocene and Miocene ages after Rö gl ( 1996); T, Global Tethys stages; PT, Paratethys.

Gray areas represent the ages used in this study. Note especially the diff erences at the Miocene/ Pliocene boundary between the ages

used in the present study and the standard Tethys scale. A, B, C represent the internal, median and external sedimentary facies of

the studied units. For B and C, only variations in respect to A were drawn. 1, 2, 3 represent results of the first, second and, respectively,

third paleostress data sets in the present paper. Deformation patterns, paleostress fields and tectonic events for the Cretaceous–Lower

Miocene and for the internal flysch and East Carpathians inner basement were taken from the results of Sandulescu (1984, 1988),

Csontos (1995), Matenco (1997), Schmid et al. (1998).


8/32



9/32


1914) or Subcarpathian (Sandulescu, 1984) nappe. 1992; Raileanu et al., 1994). The Paleozoic– Tertiary sedimentary cover (including the fore-It is mainly formed by non-outcropping Eocene todeep) of the East European platform, about 6– Oligocene clastics similar to those of the Marginal12 km (Raileanu et al., 1994), decreases towardsFolds nappe followed by molasse type sedimentsthe east. In contrast, deep reflection seismic profilesinterlayered with two main evaporitic levelsand seismological data show crustal thickness(Fig. 5). The Lower Salt formation (Earlyvalues of 34–40 km for the Moesian platform, withMiocene) is found in the internal areas and isa thicker sedimentary cover (Rãdulescu, 1988;replaced towards the east by molasse conglomer-Enescu et al., 1992).ates and the Gray Schlier formation. This salt

The East Carpathians foreland is flexed in frontformation acted during the Miocene deformationof the fold-and-thrust belt. This flexure allowedas an important decollement horizon, and its lat-for the formation of an undeformed foredeeperal distribution aff ected the thrusting geometriesbasin. The base of the foredeep, represented by(see later). Badenian tuff s, gypsum, calcareousthe top Mesozoic, deepens both towards the Wsandstone and fine-grained quartzarenitesand S from an average of 1500 m in the north to(Sandulescu et al., 1981a) follow and are overlain5000 m in the region of Bistrita valley and toby Lower Sarmatian coarse deposits which are the8000–10,000 m south of Trotus valley (Dicea,

youngest sediments of the Pericarpathian nappe1995). Flexure is accompanied by NW–SE-

(Fig. 5).trending normal faults with off sets up to 1–2 km

The Subcarpathian nappe is thrust on the East

(e.g. Vicov–Paltionoasa–Bacau, Straja–GuraCarpathians foreland platforms (Fig. 6). The East Humorului; Dicea, 1995) (Fig. 6 and profile 1,Carpathians foreland is formed by the Paleozoic

Fig. 7). Reflection seismic surveys have alsoto Cretaceous coalescence of three main lithosphe-

revealed regional NE–SW- to E–W-trendingric blocks named the East European, Scythian and

transverse faults ( Fig. 6) (Dicea, 1995).Moesian platforms (Fig. 6). The western boundary

Since the front of the East Carpathians is notof the East European platform is formed by always parallel to the TTZ, there is a diff erence inthe Tornquist–Teisseire zone [ TTZ, or Trans- the substratum on which the external nappes andEuropean Suture Zone (TESZ)], a tectonic linea- the foredeep lie. In the northern sector, the Eastment of lithospheric importance stretching from Carpathians have passed the TTZ and, togetherSweden to the Black Sea (e.g. Zielhuis and Nolet, with their foredeep, overlay the thick East1994). The TTZ separates very thick and cold East European plate (e.g. Botezatu and Calota, 1983;

European plate in the NE from thinner and Guterch et al., 1986; Pinna et al., 1991). To thewarmer Moesian lithosphere in the SW. In the south, the lithospheric transition is in a morestudy area (Fig. 6), the major lineaments related easterly position and the East Carpathians nappesto this zone are the Campulung–Bicaz fault and, and foredeep are still overlying the thinnerS of the Trotus fault, the Pecenaga–Camena fault Moesian platform ( Fig. 6) . These features have(Cantini et al., 1991), which juxtapose TTZ over important implications, which will be discussed inthe Scythian platform and the North Dobrogea a following section.orogen (Fig. 6). In the East European platform,

deep seismic reflection and refraction profiles show 2.2. Main structures along the profilesthicknesses of about 10, 20 and 40–45 km for the

base of the sedimentary cover, Conrad and Moho The deep structure of the external EastCarpathians was analysed through 14 geologicaldiscontinuities, respectively (Enescu et al., 1988,

Fig. 6. Tectonic map of the East Carpathians foreland platforms (compiled and modified from Sandulescu, 1984; Sandulescu and

Visarion, 1988; Dicea, 1995; Ellouz et al., 1994). Hatched area represents the Tornquist–Teissere zone (Cantini et al., 1991), contour

lines represent the Bouguer anomaly (Mocanu and Rãdulescu, 1994). CBF, Campulung–Bicaz Fault; SF, Straja–Gura Humorului

fault; ScF, Solca fault; SiF, Siret fault; BF, Bistrita fault; TF, Trotus fault; PCF, Peceneaga Camena fault.


10/32



11/32


profiles (Figs. 7–9, and position in Figs. 3 and 4). The Late Burdigalian age for the Tarcau and

Marginal nappes shortening is based on the syn-These profiles illustrate the studied units, from the

internal one (Tarcau) to the external nappe tectonic character of the Upper Burdigalian sedi-

ments deposited within growing synclines in the(Subcarpathian).

The Tarcau nappe is thrust by more internal frontal part of the Marginal Folds nappe (e.g.

Matenco, 1991; Dicea, 1995) and on the Lower– units (Audia, Macla nappes) during Aquitanian–

Early Burdigalian times (Sandulescu, 1984, 1988). Middle Burdigalian age of the salt breccia forma-

tion and overlying complexes which are the youn-Towards the east, the Tarcau nappe almost com-

pletely covers the Marginal Folds nappe which gest deposits below the Marginal sole thrust.

Deformation continued during Early Badenian, asoutcrops only in tectonic windows such as the

Bistrita, Oituz and Vrancea half-windows (Figs. 3 suggested by locally overthrust beds (Slanic Tuff

and Salt Formation) (Sandulescu, 1988).and 4). The eastern boundary of the Tarcau nappe

is erosional. The overall structure of the Tarcau The internal structure of the Subcarpathian

nappe (Figs. 7–9) is characterised mainly by NEnappe is a ramp anticline, with associated imbri-

cate fan of thrusts (see for instance profiles VI– to SE-vergent thrusts and high angle reverse faults,

locally organised in imbricate fans, and by fault-VIII, Fig. 8). The internal structure of the nappe

(Figs. 7–9 ) is mainly characterised by low angle related folding. Diapirs of Lower Burdigalian salt

are common (e.g. in profiles V Fig. 7; profiles VII,imbricate thrusts. The larger ones define digitations

(e.g. Tarcau, Tazlau) (Sandulescu, 1984). Along IX Fig. 8; profile XIII Fig. 9). Where the belt

strikes NNW–SSE to N–S ( i.e. the central sectors),the strike of the belt, backthrusts can be docu-mented on the basis of field structures and depth deformation is accommodated by faults with rela-

tively high angles, higher than usually observed ininterpretations. Previous studies assume that these

faults represent overturned structures, their dip- fold-and-thrust belts (profiles V–VIII, Figs. 7 and

8), associated with widespread tear faults and ‘enping direction changing at depth towards the hin-

terland (Fig. 10A). Locally, the faults are échelon’ folds (Figs. 3 and 4). This possibly reflects

thrusting associated with dextral movements alongdocumented at depth and display a normal off set,

within Cretaceous–Eocene deposits. Our inter- fault planes. The faults become flatter towards the

north, where the belt strike changes to NW–SEpretation assumes that these structures are in fact

sets of backthrusts, which may connect with fore- (profiles I–III, Fig. 7) and would therefore suggest

only thrusting. The transition from one domain toland propagating thrusts along pop-ups. Partial

inversion of former extensional faults can account the other occurs between the southern terminationof the Bistrita half window and the Trotus valleyfor the normal off sets still preserved at depth

(Fig. 10B). Backthrusting occurred also on the (Fig. 3). The amount of internal shortening is

estimated at 57% in profile III (Matenco, 1991)rear limb of ramp anticlines producing pop-up

structures such as in the Moldova valley region and is representative for the external nappes of

East Carpathians in the northern sector.(profile I, Fig. 7), or in the Buzau valley region

(profiles IX, X, Fig. 8).

The Marginal fold nappe is basically composed 2.3. The contact between nappes and the

undeformed foreland of large-scale duplexes, hinterland-dipping to anti-

formal-stack types. Internal, low- to intermediate-

dip faults merge at depth in the major detachment The Subcarpathian nappe is thrust towards the

E onto the East European/ Scythian/ Moesian plat-surfaces and are often associated with recumbent

folds (Figs. 7–9). forms. It is difficult to estimate the amount of

Fig. 7. Geological profiles in the central–northern part of the East Carpathians derived from surface geology and interpretation of

seismic sections. The names of the nappes outcropping are indicated in the upper part of the sections. Location of the profiles in Fig. 3.


12/32


Fig. 8. Geological profiles in the central–southern part of the East Carpathians derived from surface geology and interpretation of

seismic sections. Location of the profile in Fig. 4.


13/32


Fig. 9. Geological profiles in the southernmost part of the East Carpathians derived from surface geology and interpretation of

seismic sections. Location of the profiles in Fig. 4.

displacement because of insufficient information need to be described in some detail. In all profiles,

the frontal thrust cuts Lower to Middle Sarmatianon the platforms beneath the main thrust, but a

minimum value of 15–25 km can be observed deposits and is therefore younger. The upper age

limit is less constrained because the geometry of along all profiles (Figs. 7 and 8).

The kinematics and especially the age of thrust- the frontal zone changes along strike.

In the northern profiles (from I to IV) theing along the frontal thrust are controversial and


14/32


In the southernmost part of the East

Carpathians (profiles XI–XIV, Fig. 9) the

Pericarpathian frontal thrust is precisely dated,

cutting Lower to Middle Sarmatian deposits but

being sealed by the Uppermost Sarmatian

sediments.

In the central bending area, Latest Miocene–

Early Pliocene shortening along the frontal sole

thrust was accommodated by out-of-sequence

thrusting in the more internal parts of the orogen

and Transylvania basin (Sanders, 1998; Ciulavu,

1999).Fig. 10. Cartoon illustrating (A) previous structural interpreta-

tion of hinterland-vergent thrust faults overturned in depth to

hinterland-dipping normal faults (e.g. Stefanescu and working3. Field structuresgroup, 1988); (B) inversion mechanism of an inherited normal

fault along a frontal thrust and a backthrust, organised in a

pop-up structure. Structural data were collected in the external

nappes (Tarcau, Marginal, Subcarpathian) of the

East Carpathians and in the adjacent foredeepmajor thrust outcrops at the surface, cutting

through Lower to Middle Sarmatian sediments between the Moldova valley in the north, and theOituz valley in the south (Fig. 3). For the regional(Fig. 7). Consequently, the age for the cessation

of thrusting is poorly constrained. Some second- correlation we have used literature data (e.g.

Sandulescu, 1984, 1988; Sandulescu et al., 1981a,b;order complications might be present in profiles

I–III, where the thrust is decomposed in a leading Stefanescu and working group, 1988; Micu, 1990;

Morley, 1996), and geological maps 1:200,000 andimbricate fan. Locally, Uppermost Sarmatian–

Lowermost Meotian sediments seal the frontal sole 1:50,000 published by the Geological Institute of

Romania.thrust, indicating a Late Sarmatian thrusting age.

Moving southward the geometry of the frontal

zone changes and the Subcarpathian nappe is 3.1. Data and methodsunconformably overlain by Upper Sarmatian

deposits dipping to the E (profiles V to IX). This Brittle structures such as fault striations, folds,tension joints, fault-related folds (fault propaga-contact has been traditionally considered in sub-

surface interpreted profiles as stratigraphic and, tion, drag folds), regional-scale faults have been

analysed in 90 stations in Upper Cretaceous totherefore, indicative of the end of thrusting.

However, the overall position, and particularly the Sarmatian sediments belonging to the thrust sheets.

Regional paleostress directions were reconstructedE-ward dip of the Upper Sarmatian reflectors,

suggest that this surface is a backthrust. In the using fault slip data sets collected in 67 stations

along the belt. For a similar and more completefrontal areas, therefore, a triangle zone is formed,

with the described backthrust compensating the description of the methods used, see Matenco and

Schmid (1999). Fault planes with slickensides aredisplacement of the Pericarpathian fault. Younger

salt diapiric movements overprint the boundary the most common structures measured. Roughly

1400 faults with direction and sense of slip werezone at the front of the Subcarpathian nappe

(Magiresti–Perchiu line, after Sandulescu, 1984; measured, each site having between nine and 120

measurements. The slip sense was deduced frome.g. profile V, Fig. 7). The dip of the backthrust is

relatively shallow in the Trotus valley region, but kinematic indicators along the fault plane, such as

mineral steps, tension gashes, Riedel shears, frac-increases towards the south (see for instance profile

VII and VIII). These features point to a post tures with tension planes, in-plane conjugate shear

fractures, conjugate fault planes (for a completeUpper Sarmatian age of thrusting.


15/32


review see Angelier, 1994), or rare shear bands traction axis and the shear plane is a direct function

of the material properties.(Simpson and Schmid, 1983) in the case of more(3) The Spang (1972) numeric dynamic analysiscomplicated shear zones. The quality of slip sense

method. In addition to the Turner method, thewas classified in the field as certain (37% of faultSpang (1972) method is computing a reducedpopulation), probable (54%), supposed (12%), orstress tensor, the relative values of the principalunknown (7%). Relative chronological constraintsstresses being calculated from the mean values andwere obtained in the field in approximately 30%vectors of the bulk stress tensor.of the locations, using criteria such as cross-cutting

The most reliable stress axis determinations arerelationships, successive striations along a faultthose provided by the Angelier method. In casesplane and reactivations of conjugate faults. In eachof ambiguous solutions we have used the otherlocation, subsets of fault–slip data consistent withtwo methods to double-check and further constrainvarious stress directions were separated, on thethe stress field.basis of the stress regime type/ orientation and on

In places with a low number of measurements,the chronological constraints. Where a sufficientlythe inversion method was combined with paleo-large number of faults/ subsets could be measured,stress determinations from two conjugate faultsdata sets were analysed using three methods:(e.g. Angelier, 1984), minimisation of s

n on tension(1) The Angelier (1984, 1989) inverse method,

joints (Delvaux, 1993) and fault-related fold axisthat finds the best possible fit between observedanalysis. For the sake of simplicity, only the twofault–slip data and computed shear stresses gener-conjugate faults were plotted as faults with slipated on the fault planes. We have used the Delvauxsense (stereoplots in Figs. 11A, 13A, 14A).

(1993) method and software, which starts fromFor the definition of the stress field we have

the tensor given by the right dihedron methodused the nature of the (sub)vertical stress axis and

(Angelier and Mechler, 1977). This tensor is firstthe value of ratio R (Delvaux et al., 1997), if

optimised automatically ( least squares method)computed (Table 1). For the regional stress field,

and second manually, in order to obtain the bestall the stress tensors related to a given deforma-

mentioned fit (usually minimising a mean sliptional stage, as obtained by these methods, were

deviation). The limitations of this method concern-plotted in a single diagram (Figs. 11B, 13B, 14B).

ing the tensors and isotropy are discussed inStatistical calculations of the cone of confidence

detail elsewhere (e.g. Etchecopar et al., 1981;for each deformation stage and regional deviations

Angelier, 1984; Dupin et al., 1993; Pollard et al.,

were performed, using the Wallbrecher (1986)1993). The method allows for the definition of method and software.the orientation of principal stress tensors Regional timing constraints were obtained(s

1≥s

2≥s

3) and the ratio R between stress magni- through correlating the chronological constraints

tudes [R=(s2−s

3)/ (s

1−s

3)] for a single deforma- observed in the field with the deformation age of

tion period (Tables 1 and 2 and Figs. 11A, 13A, the sediments, observed at the surface and in14A). On the basis of the slip sense quality and interpreted geological profiles ( i.e. orientation of TQR indicator (tensor quality rank, Delvaux 1993; fault planes, similar type of kinematics and chro-Delvaux et al., 1997), each tensor was classified as nology). In addition, the age of the ENE–WSWgood (TQR≥1.5, 7% from the total number of compressional stress regime (see below) was corre-tensors), medium ( 0.5≤TQR


16/32


Table 1

Location stations and parameters of paleostress reconstruction. s1≥s

2≥s

3, azimuth and dip of principal stress axes. R ratio=stress

ellipsoid shape factor, R=(s2−s

3)/ (s

1−s

3). a represents the mean slip deviation between the measured kinematic indicator on fault

plane and the orientation of the calculated shear stress. n/ N represents the number of faults generating a stress tensor versus the total

number of faults in the index. TQR=tensor quality rank (Delvaux et al., 1997), TQR=n(n/ N )/ a. Stress fields may vary from

extension (s1

vertical ), with pure extension (0.25


17/32


Table 1 (continued )

Station Latitude Longitude Direct inversion (TENSOR ) n/ N TQR Rock age

(deg min s) (deg min s)

s1

s2

s3

Ratio a

EC44a-CP2 46 20 10 26 14 08 177/ 48 83/ 03 350/ 42 0.47 9.29 15/ 18 B-1.34 lt

EC44b-SEN 46 19 54 26 21 28 37/ 38 172/ 42 286/ 24 0.69 17.17 8/ 08 B-0.52 Sn

EC44b-CP2 46 19 54 26 21 28 125/ 22 226/ 26 0/ 55 0.25 13.55 8/ 14 C-0.33 Sn

EC46-CP1 46 29 54 26 29 04 250/ 25 355/ 28 126/ 51 0.33 21.10 21/ 24 A-0.87 Pg3

EC46-SEN 46 29 54 26 29 04 220/ 40 20/ 48 121/ 10 0.34 15.58 8/ 11 C-0.37 Pg3

EC47-CP2 46 33 39 26 27 39 130/ 06 35/ 40 227/ 50 0.06 16.37 13/ 19 B-0.54 Pg3

EC48-SEN 46 34 37 26 27 02 30/ 19 209/ 71 300/ 00 0.30 14.45 7/ 07 C-0.48 Pg3

EC48-CP2 46 34 37 26 27 02 330/ 11 105/ 75 238/ 11 0.29 12.37 14/ 15 B-1.05 Pg3

EC49-CP2 46 26 21 26 22 12 310/ 15 69/ 61 213/ 24 0.50 12.75 11/ 14 B-0.67 lt

EC49-CP1 46 26 21 26 22 12 236/ 23 331/ 12 87/ 64 0.30 6.99 8/ 09 A-1.01 lt

EC50-CP1 46 27 08 26 11 46 250/ 22 155/ 12 39/ 65 0.12 9.69 7/ 07 B-0.72 lt

EC50-SEN 46 27 08 26 11 46 47/ 30 227/ 60 317/ 00 0.75 11.82 12/ 12 B-1.01 lt

EC50-CP2 46 27 08 26 11 46 152/ 01 62/ 08 251/ 82 0.35 13.70 12/ 15 B-0.70 lt

EC51-SEN 46 31 37 26 30 30 215/ 06 313/ 53 120/ 37 0.31 16.39 17/ 21 B-0.83 Pg3, Bd

EC52-CP1 46 33 26 26 31 06 288/ 34 197/ 02 104/ 56 0.40 14.06 8/ 10 C-0.45 Pg3

EC53-CP1 46 35 23 26 29 32 80/ 04 172/ 26 342/ 64 0.56 18.73 16/ 19 B-0.71 Pg3

EC53-SEN 46 35 23 26 29 32 45/ 04 299/ 75 136/ 14 0.14 13.84 13/ 18 B-0.67 Pg3

EC54-SEN 46 37 35 26 26 24 41/ 23 225/ 67 131/ 02 0.53 15.75 25/ 33 B-1.20 Pg3EC55-CP2 46 40 28 26 26 34 145/ 25 240/ 11 351/ 63 0.50 8.17 10/ 17 B-0.71 Pg3

EC56-SEN 46 48 55 26 08 36 33/ 20 219/ 70 124/ 02 0.59 15.28 21/ 27 B-1.06 lt

EC57-SEN 46 42 54 26 12 11 29/ 09 264/ 74 121/ 13 0.53 16.72 8/ 11 C-0.34 lt

EC58-SEN 46 46 59 26 06 24 235/ 26 81/ 62 330/ 11 0.50 10.81 10/ 13 B-0.71 Pg1

EC59-SEN 46 53 34 26 03 36 18/ 29 240/ 53 120/ 21 0.63 14.99 15/ 20 B-0.75 lt

EC60-SEN 46 56 21 26 05 56 355/ 23 192/ 66 88/ 06 0.43 12.11 9/ 14 C-0.47 Pg1

EC60-CP2 46 56 21 26 05 56 160/ 09 255/ 30 55/ 58 0.43 13.72 12/ 16 B-0.65 Pg1

EC61-CP1 46 56 14 26 07 21 203/ 21 97/ 35 318/ 47 0.03 12.25 7/ 07 B-0.57 Sn

EC61-CP2 46 56 14 26 07 21 323/ 04 65/ 72 232/ 18 0.00 16.41 9/ 10 B-0.51 Sn

EC62-CP1 47 03 46 26 03 17 205/ 16 115/ 01 22/ 74 0.20 13.65 18/ 20 B-1.18 Sn

EC63-CP1 47 35 00 25 40 50 212/ 19 121/ 02 25/ 71 0.29 8.51 9/ 13 B-0.73 Pg3

EC64-CP1 47 32 32 25 48 08 255/ 05 164/ 08 15/ 80 0.30 12.82 8/ 10 B-0.51 Pg3

EC64-SEN 47 32 32 25 48 08 43/ 12 228/ 78 133/ 01 0.18 11.81 21/ 27 B-1.38 Pg3

EC65-SEN 47 27 45 25 48 26 248/ 13 1/ 60 151/ 27 0.65 13.31 8/ 09 B-0.53 Pg3

EC66-SEN 47 32 15 25 52 49 205/ 11 358/ 78 114/ 05 0.68 18.08 7/ 07 C-0.38 Bn

EC67-CP1 47 35 10 25 51 24 232/ 23 331/ 20 98/ 59 0.40 11.55 16/ 17 B-1.30 Pg1-lt

(Morley, 1996; Hyppolite and Sandulescu, 1996; deformations are presented in a later section of

the paper.Zweigel et al., 1998; Ciulavu, 1999) integrated with

our own observations.

3.2.1. WSW–ENE shortening

The first data set (stereoplots in Fig. 11) is3.2. Central East Carpathians

characterised by a compressional stress regime

with WSW–ENE-oriented s1

( Fig. 11). A fairlyWe present evidence for three major Tertiary

tectonic events in the studied units, illustrated in good concentration of the obtained tensors is

observed (Fig. 11B). The slip deviation factor (b)an old-to-young succession. For each stage we will

discuss first the general stress parameters and the which ‘compares’ the observed faults with the

shear plane determined by the tensor is low, sug-fault data, and second the significant associations

of structures observed in outcrops. Large, map- gesting that deformation was accommodated along

well-grouped fault directions ( Fig. 11C and D).scale structures that can be correlated with these


18/32



19/32


Table 2

Statistical calculations of the general parameters of the stress fields for each determined stage. Stress axes, R ratio, and slip deviation

are statistically averaged from the results obtained from the direct inversion method (Direct inversion), the numeric dynamic analysis

method (Numeric), and the PT axes method (PT axes). Statistical parameters obtained are preferred orientation (PO), concentration

parameter (CO), cone of confidence (CC) and spherical aperture (SA) (Wallbrecher, 1986)

Direct Inversion Numeric PT Axes Statistic parameters

PO (%) CP CC (°) SA (°)

Stage CP1

s1

241/ 15 238/ 11 245/ 08 70.70 6.56 15.14 32.77

s2

338/ 04 148/ 03 155/ 02 72.49 6.99 14.59 31.63

s3

64/ 80 44/ 78 52/ 82 84.91 12.74 10.43 22.86

Ratio R – 0.56 – – – – –

Slip deviation 12.81 – – – – – –

Stage CP2

s1

149/ 09 148/ 16 148/ 15 83.73 11.52 14.49 23.79

s2

245/ 14 245/ 24 244/ 20 75.06 7.40 21.04 29.96

s3

26/ 70 28.61 23.65 79.24 8.89 18.94 27.10

Ratio R – 0.38 – – – – –


Stage SEN s1

30/ 06 38/ 08 36/ 08 65.63 5.65 14.09 35.89

s2

252/ 82 252/ 81 250/ 81 79.75 9.60 10.37 26.74

s3

117/ 07 129/ 05 132/ 4 61.66 5.07 15.07 38.26

Ratio R – 0.64 – – – – –


The ratio R indicates pure compression for the this WSW–ENE compression are common and

form the dominant grain of the belt. They trendmajority of the stations. A strike–slip component

associated with the inverse-dextral faults can be predominantly NNE–SSW to N–S in the southern

and central sectors and NW–SE in the northerndefined only for four stations (EC28, 30, 31, 33,

Fig. 11A). Generally, the s1 orientation tends to ones (Fig. 11A). Forethrusts dominate and arecommonly associated with backthrusts. Similarbe perpendicular to the dominant strike of the

belt, i.e. from E–W to ENE–WSW in the south to features are observed in representative outcrops.

In station EC1, located near the base of theNE–SW oriented s1

in the north (Fig. 11A). The

age of the youngest sediments in which paleostress Marginal Folds nappe (Fig. 12A) two sets of con-

tractional structures are recorded. The older onesmeasurements were performed is Lower

Burdigalian. are foreland-vergent folds often associated with

thrusts in their cores. These folds are truncated byFaults and folds that can be associated with

Fig. 11. ( A) Geological–structural map of the studied area with paleostress tensors associated with the Late Burdigalian–Sarmatian

compressional event. Mean regional stress values of s1=241/ 15±15°,±15°, s

2=338/ 04±15°, s

3=64/ 80±10°,±15° and±10° being

the aperture of the cone for 95% confidence, were computed using the Wallbrecher (1986) method. Structures (faults, folds, nappe

contacts) active at the time are evidenced with thicker black lines. Stereoplots represent the paleostress results for the WSW–ENE

(CP1) shortening event. Only faults with a certain sense of movement have been plotted (70% of fault population). (B) Principal

stress axes derived from the direct inversion method. (C) Projection of the measured compressional (small circles) and tensional

(small squares) axes for each fault in the measured set, and projection of mean compression, tension and medium directions, computed

using the Turner method. (D) Hanging-wall movements for all faults, and principal stress axes computed for the whole faults set

using the numeric dynamic analysis (NDA) method.


20/32


Fig. 12. (A) Sketch and stereoplot of the outcrop structures in station EC1. Note the development of hanging-wall anticlines and

recumbent folding and subsequent out-of-sequence thrusting. Stratigraphy: Lower menilites and bituminous marls formation

(Oligocene). Unit: Tarcau nappe. ( B) Sketch and stereographic projections of the outcrop structures in station EC15. Stratigraphy:

Doamna limestone (Eocene). Unit: Marginal Folds nappe. Description in the text. (C) Sketch and stereographic projection of the

outcrop structures in station EC68. Stratigraphy: Upper gypsum formation. Unit: Subcarpathian nappe. Description in the text.

thrusts faults with correlative ramp folds. Vergence In station EC68 (Trotus valley) (Fig. 12C),outcrop-scale folding is associated with E-wardof the younger thrusts is towards the ENE. The

shortening direction is ENE–WSW for both sets thrusting. All the structures are formed in the

hinge of an approximately 200 m wavelengthof structures, thereby suggesting that they belong

to the same deformation phase. anticline.

In station EC15 (Fig. 12B), the Eocene

Doamna limestone forms an asymmetric anticline 3.2.2. Strike–slip regime

The second data set (stereoplots of Fig. 13) is(approximately 800 m wavelength) with E-ward

vergence and slight S-ward axial plunge. Second- characterised by a strike–slip regime with NNE–

SSW-oriented s1

and WNW–ESE-oriented s3

order structures such as parasitic folds, low-angle

thrust faults on the normal limb, high-angle inverse ( Fig. 13). The concentration of the obtained ten-

sors is good (Fig. 13B). The slip deviation fromfaults on the steep limb and thrust-ramping along

the hinge are common. Faults formed in the initial the theoretical general tensor is low, reflecting

deformation along fault planes with fairly constantstages of deformation accommodating layer paral-

lel shortening, and were subsequently passively strike along the belt (Fig. 13C and D). Most R

ratios demonstrate a pure strike–slip character.rotated during folding. Shortening directions are

compatible with those derived for the large-scale Tensional/ strike–slip R values are found mainly

in or near the Comanesti depression. Afold.


21/32


Fig. 13. Results of the paleostress analysis for the Late Sarmatian strike–slip (SEN) event. Mean regional stress values are

s1=30/ 06±14°, s

2=252/ 82±10°, and s

3=117/ 07±15°. Conventions as in Fig. 11.


22/32


compressive/ strike–slip character is observed in a In the Early Miocene–Sarmatian, NW–SE com-

pression led to the major thrusting and folding of few stations located close to the contact with

Subcarpathian nappe, or in the nappe itself (e.g. the Moldavides nappes (Fig. 15). North of the

Buzau Valley, the maximum stress axes trendEC21, EC28, EC53, Fig. 13A). The youngest sedi-

ments in which these measurements were per- WNW–ESE, and are thus parallel with the trans-

port direction. These conclusions are compatibleformed are Upper Burdigalian.

Outcrop-scale structures developed during this with results obtained by Morley (1996) according

to whom regional Miocene shortening is character-stage are common and are mainly strike–slip faults

( Fig. 13A). Sinistral transcurrent faults dominate. ised by a stress field with roughly E–W contraction

direction north of the Buzau Valley, changing toThey strike ENE–WSW in the central sectors and

NE–SW in the northern ones. Dextral, NNE– NW–SE south of it (Fig. 15). These data are also

compatible with our observations from the north-SSW conjugate faults are subordinate (Fig. 13A).

Large-scale structures associated with this stage ern segment of the East Carpathians.

No strike–slip stress field has been explicitly(Fig. 13) can be observed over the entire studied

area. Sinistral faults clearly dominate and are E– reported for the external East Carpathians bending

area. However, a large number of published paleo-W to WNW–ESE directed in the area of Trotus

valley, and E–W to WSW–ENE north of this stress stations have a clear strike–slip character

and spatially coincide with large-scale transpressivevalley. Conjugate, N–S oriented dextral faults were

formed locally as reactivation of the older roughly structures. For instance, a large part of the tensors

obtained by Hyppolite and Sandulescu (1996)N–S trending thrust contacts.(Fig. 15) displays a strike–slip character with NE–

SW compression axes. The age of this stress field3.2.3. NNW–SSE shortening

The third data set (stereoplots of Fig. 14) is is considered by the authors as Miocene without

further specification. In addition, according tocharacterised by a compressional regime with

roughly NNW–SSE-oriented s1

(Fig. 14). The ori- Zweigel et al. (1998), brittle deformation of base-

ment and Mesozoic sedimentary cover in theentations of the calculated tensors have a certain

degree of dispersion, reflected by high slip devia- internal part of the East Carpathians bend zone

occurred exclusively in strike–slip with NW–SEtion from the general theoretical shear planes

(Fig. 14C and D). R values show pure compres- contraction direction and extensional modes. The

same authors recognised, in the external part of sional to strike–slip compressional character.

Three stations (EC48, 29, 61) have a pure strike– the East Carpathians bend zone, two groups of brittle structures. The first and larger group hasslip character (Fig. 14A). The age of the youngest

sediments in which such tensors were obtained is contraction axes oriented WNW–ESE to NNW–

SSE, interpreted to be coeval with the Paleogene– Lower Miocene.

Outcrop-scale faults ( Fig. 14A) are thrusts with Miocene shortening. The second group is younger,

has N–S- to NNE–SSW-oriented contractionalSE vergence and secondary thrusts with NW

vergence. Large-scale structures associated with axis, and is interpreted to be coeval with the Late

Miocene–Quaternary shortening. Roughly 40% of this deformation ( Fig. 14A) are rare. However,

SSE-vergent thrusts can be documented in the these paleostress stations have a strike–slip charac-

ter with NW–SE to NNE–SSW, both groups beingComanesti area, in the Tarcau nappe and around

Piatra Neamt. compatible with our observations and with the

strike–slip stress field with NW–SE to N–S direc-

tion observed in the external South Carpathians3.3. Southern East Carpathians

(see also Ratschbacher et al., 1993; Matenco et al.,

1997a; Linzer et al., 1998). Since there is no realBased on the work carried out in the area by

several authors (e.g. Hyppolite and Sandulescu, evidence in the subsurface for any kind of

Paleogene tectonics (e.g. Stefanescu and working1996; Morley, 1996; Zweigel et al., 1998) three

deformation stages can be identified. group, 1988; Ionescu, 1994; Dicea, 1995, 1996; and


23/32


Fig. 14. Results of the paleostress analysis for the Pliocene shortening (CP2) event. Mean regional stress values are

s1=149/ 09±14°, s

2=245/ 14±21°, s

3=26/ 70±19°. Conventions as in Fig. 11.


24/32


Fig. 15. Compilation of paleostress measurements performed in the southern East Carpathians bending area (after Morley, 1996;

Hyppolite and Sandulescu, 1996).

review of Sandulescu, 1988), we are correlating The Pliocene ( Wallachian) deformation stage is

characterised in the southern part of the Eastthe first group with the Middle to Late Miocene

shortening depicted by our study in the external Carpathians by roughly N–S to NNE–SSW com-

pressional axes (Hyppolite and Sandulescu, 1996)East Carpathians.


25/32


as demonstrated by paleostress tensors in several vergent imbricate thrusts, backthrusts, duplexes

and associated ramp folds with several hundredlocalities of the external nappes, especially between

the Dambovita and the Buzau Valleys (Fig. 15). metres to some kilometres off set developed during

this stage (Figs. 7–9). The distribution and thick-

ness of the competent Tarcau sandstone exerted a

fundamental control on the geometry of shorten-4. An integrated tectonic model

ing. Large values are observed in the internal parts

of the Tarcau nappe where this horizon is largelyIn this section we integrate the data derived

from surface structural work and the available developed. North of the Bistrita valley or towards

the foreland, where this horizon is thinner, thrustssubsurface information into a kinematic model of

the Central East Carpathians during Miocene and are more closely spaced and the amount of internal

shortening higher (Figs. 7–9 ). In the MarginalPliocene times. Since Neogene to Quaternary struc-

tures are partly controlled by Paleogene deforma- Folds nappe (Figs. 7–9 ) deformation is accommo-

dated by more tightly imbricated thrust faults,tion (e.g. Ellouz and Roca, 1994), a brief summary

is given on the Paleogene evolution. large duplex systems and recumbent folding with

overturned foreland limbs. Detachment folds are

common in and above the Lower Cretaceous black4.1. Paleogene tectonics

shales, which is the lowest detachment horizon in

the Tarcau and Marginal units (e.g. profile 7,The Paleogene history of the East Carpathians

is characterised by extensional deformation mainly Fig. 8).Beginning with the Sarmatian, the Tarcau nappeof Eocene age, stretching being accommodated by

N–S-trending, mainly eastward-dipping normal was transported onto the Marginal Folds nappe

and thrusting continued its forward propagation,faults (Sandulescu, 1992). Some of these faults

have been imaged in seismic lines across the belt aff ecting the Subcarpathian nappe with NNE–

SSW- to NNW–SSE-oriented thrusts and folds(Figs. 7 and 8) where they appear to have been

subsequently inverted. Thick, coarse-grained sand- ( Figs. 3, 4 and 16A). Out-of-sequence thrusts and

backthrusts also formed in the more internalstones in the western nappes (Tarcau sandstones)

were deposited in the proposed extensional basin. Tarcau and Marginal units. Sedimentary basins

developed in a piggy-back fashion during the EarlyThis extensional episode is correlative in geometry

and time with the Paleogene extension documented to Middle Sarmatian, the most important being

the Comanesti basin (Fig. 11A).in the South Carpathians, at the Getic/ Danubiannappes contact (Schmid et al., 1998; Matenco and During the Sarmatian, the Subcarpathian nappe

was eventually thrust over the undeformed fore-Schmid, 1999) and within the Getic Depression

(Matenco, 1997; Rabagia and Matenco, 1999). land along the Pericarpathian fault. The termina-

tion of movements along this thrust fault is

diachronous. It is Late Sarmatian north of the4.2. Late Burdigalian–Sarmatian thrusting

Trotus fault and in the southernmost part of the

East Carpathians, but it becomes younger, EarliestThe first tectonic event that aff ected the studied

area was ENE–WSW- to ESE–WNE-directed Pliocene, in the central bending area (Figs. 3 and

4). Diff erences in thrusting age were taken up byshortening (Fig. 16A) responsible for the ENE- to

ESE-vergent thrusts present in all studied nappes. various transfer zones, as for instance the Trotus

fault, a deep basement fault forming the boundaryDeformation began in Middle Miocene (Late

Burdigalian) times and continued until the between the East European and the Scythian plat-

forms (Sandulescu and Visarion, 1988) ( Fig. 6),Sarmatian.

In the initial, Middle Miocene (Late which acted as a sinistral transfer zone during this

time interval.Burdigalian–Badenian) stages, deformation

aff ected the more internal nappes of the system, A significant coeval structure is the northern

limit of the Bistrita half-window, where thethe Tarcau and Marginal Folds nappes. Foreland-


26/32


Fig. 16. Sketch of the Tertiary tectonic evolution of the Romanian East Carpathians. Description in the text.

Tarcau/ Marginal contact is right-laterally transfer- 4.3. Latest Sarmatian–Early Meotian strike–slipred ( Fig. 11A). This dextral movement aff ects the

trend of faults and fold axes, which swing from The second deformation stage developed in a

strike–slip regime with NNE–SSW to N–S com-NNW–SSE to NE–SW and then back to NNW–

SSE. Tear faults continue both towards more pressional axes (Fig. 16B). Structures are not

homogeneous across the entire Romanian Eastinternal areas and towards the foreland (Fig. 11A),

and are kinematically linked with a major W–E Carpathians and two diff erent zones can be

recognised.trending fault segmenting the foredeep basement

(Fig. 6), its northern block being roughly 2000 m In the northern zone, extending from the

Moldova Valley in the north to the Oituz half-uplifted (Dicea, 1995). A major change in the

thrusting geometry occurs across this fault. The window in the south (Fig. 13A), strike–slip defor-

mation was predominantly accommodated bylarge-scale antiformal stack developed in the

Marginal nappe and correlative ramp faults in the ENE–WSW-trending sinistral faults. Sinistral

faults of regional importance develop at the south-Tarcau nappe (profile II, Fig. 7) present north of

the fault are replaced to the south by hinterland- ern termination of the Bistrita half-window and

along the Trotus valley (Fig. 13A). The northerndipping duplexes developed in the Marginal Folds

nappe associated with an imbricated thrust system sinistral fault has an off set of ca. 10 km and is

kinematically linked with the reactivation of ain the Tarcau nappe (profile III, Fig. 7).


27/32


deeper structure aff ecting the thrusted foreland Meotian sediments sealing numerous transcurrent

faults.platform (Bistrita fault, Fig. 6; see also Dicea,

1995). The second major structure is the E–W4.4. Pliocene–Pleistocene thrusting Trotus fault, separating the Scythian and the

Moesian platforms. Its crustal importance is sug-The last tectonic event aff ecting the area is thegested by the 30 km sinistral displacement shown

roughly NNW–SSE-oriented shortening (Fig. 16C).by the Bouguer anomaly contours across the faultDeformation in the northern part of the studied areazone (Fig. 6). The sinistral reactivation of theis diff use and mainly represented by small-scaleTrotus fault caused widespread deformation in thethrusting with SSE vergence (Fig. 14A). Thrustsoverlying flysch units (Fig. 13A). Faults belongingrelated to this stage cut Late Sarmatian strike–slipto this system cut older thrusts both in outcropfault and are therefore Pliocene or younger.and in map view (e.g. the contact between Audia

Large-scale structures associated with this stageand Tarcau nappes in the west and the frontalare common in the southern sectors, i.e. from thethrust of the Subcarpathian nappe in the east,Buzau Valley southward (Fig. 4). Here, deforma-Fig. 13A).tion in the Subcarpathian Nappe is mainly charac-In the S-most part of the East Carpathians,terised by out-of-sequence, E–W-trending thrusts,Latest Sarmatian–Early Meotian deformation waswhich aff ect deposits as young as the Uppermainly accommodated by WNW–ESE- to NW– Pliocene–Pleistocene (Fig. 9). Off sets up to 2000 mSE-trending dextral strike–slip faults (Fig. 4).are locally observed along these thrust faults (e.g.They are often transpressional, forming positivethe Apostolache, Urlati, Valenii de Munte, Valea

flower structures (e.g. the Moreni, Cimpina andLunga, Moreni structures, Fig. 9). The total

Valenii de Munte lineaments, Fig. 9), the associ-amount of deformation accommodated during this

ated E–W-trending anticlines being arranged ‘eninterval is of the order of 15–20 km (see also

échelon’. In the frontal part of the SubcarpathianMatenco et al., 1997).

nappe south of Buzau, E–W-trending thrusts are

common (Fig. 4), their activation being related to

the reactivation of older pre-existing normal faults5. Structural evolution and the shape of the East

during the Latest Sarmatian times (see alsoCarpathians

Rabagia and Matenco, 1999).

Strain was partitioned between the sinistral

On a regional map view, the Romanian Eastfaults developing in the northern part of the Carpathians show two quite abrupt changes in theRomanian East Carpathians and the dextral faults dominant trends. The overall structural grain of in the southern one. This resulted in a movement the belt is NW–SE in northern Romania and intowards the SSE of the central, intermediate sec- adjacent Ukraine, changes to a N–S direction intors, and an increase of curvature of the southern correspondence with the Moldova valley, andpart of the fold belt (Fig. 4). As a result, contracti- assumes an E–W direction at the junction with theonal structures developed during this time span in South Carpathians (Fig. 1). In both cases an oro-the bending area, compatible with the diff erent clinal bending of the already structured fold-and-age, Latest Sarmatian–Early Meotian, of the fron- thrust belt is unlikely, because of the absence/ tal sole thrust. In the internal zones, the SSE-ward insufficient amount of accommodating extensionalmovement of the bending area is accompanied by features (Marshak, 1988) in the external parts of extension and strike–slip movements (e.g. the fold-and-thrust belt and in the adjacent fore-Girbacea and Frisch, 1998; Ciulavu, 1999). land (for a complete description see Morley, 1996;

The total displacement accommodated by Zweigel et al., 1998). Therefore, the observedLatest Sarmatian–Early Meotian strike–slip is of changes should relate to pre-contractional featuresthe order of some tens of kilometres. Deformation such as irregular plate boundaries or lateral

changes in the characteristics of the sedimentaryended in the Early Pliocene, as documented by


28/32


package entering the subduction zone and involved associated with a high number of backthrusts) and

in thrusting. Additionally, they could be at least high foreland advancement (Nieuwland andpartly related to the polyphase tectonic history. Walters, 1993). Both processes seem to apply in

We propose that the change in direction taking the East Carpathians. Indeed, in the northern part,place across the Moldova valley (Fig. 3) is associ- where the Tarcau nappe is very thick, especially atated with lateral changes of the sediments pre- the Paleocene–Eocene level (e.g. thick Tarcauviously lying on top of the subducting plate and sandstone) (Fig. 17A), thrust sheets are widelyinvolved in thrusting. According to this view, spaced. In the same region, the basal detachmentchanges in directions (oroclines) are ‘passive’ fea- layer is either the Lower Cretaceous black shalestures associated with diff erential wedge geometries. in the Tarcau and Marginal nappes, or LowerTwo parameters are known to exert a primary Burdigalian and Badenian evaporitic (mainly salt)influence on thrusting geometry and thus on the in the Subcarpathian nappe. In the northern partwidth of the accretionary wedge, the thickness of of the East Carpathians, on the contrary, thethe sediments involved in thrusting and the friction wedge is narrower and has a high degree of internalat the main detachment surface (Fig. 17A). Thick shortening (duplexes, antiformal stacking). This issedimentary packages create wide wedges and compatible with the lower thicknesses of thewidely spaced thrusts (e.g. Marshak and Tarcau sandstone in the region and of the shalesWilkerson, 1992). On the other hand, low friction and evaporites acting as detachment layer. Alongsurfaces cause low internal shortening (ramping strike, changes in the thickness of the Tarcau

sandstone have been attributed to Paleogene

stretching events (Sandulescu, 1992; Matenco,

1997).

Other changes in deformation geometries are

related to lateral variations of the lithospheric

characteristics of the thrusted platforms entering

the subduction zone. In the late Miocene, the most

advanced East Carpathians nappes (central sec-

tors) reached the East European block north of

the Trotus valley. The introduction into the system

of lithospheric block with up to 50 km thick crust

and very thick lithosphere (Rãdulescu et al., 1976;

Zielhuis and Nolet, 1994; Guterch et al., 1994)

imposed changes on thrusting geometries

(Fig. 16A). The most important was the onset of

substantial uplift in the rear part of the wedge,

associated with the activation of regional

backthrusts in the internal part of the orogen

(Sanders, 1998), and further in the Transylvania

basin (e.g. Ciulavu, 1999). Similar structures are

also found further to the south, but in a much

more external position (i.e. Tarcau and

Subcarpathian nappes, Matenco, 1997). SuchFig. 17. (A ) Lateral variations in thrusting geometry due to changes are not observed in the southern segmentsvariations in wedge thickness and decollement friction (after of the chain where the thinner Moesian plate isNieuwland and Walters, 1993). (B) Flexural modelling results

involved in subduction.(after Matenco et al., 1997b), which indicate possible mecha-

One of the most interesting features of the Eastnisms of slab break-off and slab tearing for the EastCarpathians foreland platforms and their distal components. Carpathians is the SW bend area, where the struc-


29/32


tural grain changes from N–S north of the Buzau Carpathians. Deformation generally propagated

from the more internal to the more external unitsValley, to NE–SW and further E–W southward

(Fig. 4). Almost all published studies (e.g. and in the Sarmatian the ‘molasse’ deposits of the

Subcarpathian nappe were thrusted on top of theSandulescu, 1984; Morley, 1996; Hyppolite and

Sandulescu, 1996; Zweigel et al., 1998) assume foreland platforms. These frontal movements were

accommodated with foreland-vergent thrusts inthat individual structures in the external East

Carpathians nappes are continuous and follow the the north and with a backthrust associated with a

triangle zone in the south. The oroclinal shape of belt bend across the SE corner. The low values

deduced in these studies for the required orogen- the thrust belt must have been initiated in the later

deformation moments due to the irregular plateparallel extension (15–20% after Morley, 1996;

Zweigel et al., 1998) through surface kinematics boundaries and the lateral variations in thickness

of the sedimentary wedge involved in shortening.or mapping are moreover not supported by the

subsurface images, i.e. no such types of structure During Late Burdigalian–Sarmatian times, the

thrust front in the northern part of the belt reachedwere observed by extensive exploration studies in

the external East Carpathians nappes (e.g. and moved over the TTZ and the East European

Platform (Ellouz and Roca, 1994). As a conse-Stefanescu and working group, 1988; profiles A9–

A22, Ionescu, 1994; Dicea, 1995, 1996, or unpub- quence of the interactions with the East European

plate, backthrusts were activated in the internallished data of Petrom RA). This observation and

our data suggest that the main structures that parts of the orogen and important exhumation

took place. Fission track analysis (Sanders, 1998)developed at the surface of the ‘oroclinal bending’formed during diff erent episodes of deformation. show that exhumation and cooling became impor-

tant in the internal East Carpathians at 11–13 MaDuring the Middle to late Miocene shortening,

thrusts and backthrusts with NNE–SSW strike (Late Miocene). The Late Burdigalian–Sarmatian

tectonic phase is mainly responsible for the presentwere formed in the northern part of the bend area

(Fig. 4). Southward, oblique E–W thrusting day geometry of the East Carpathians and to the

up to 4 km accelerated exhumation of the rocksoccurred, possibly in association with dextral

translation along the thrust planes. Further WSW- (e.g. Sanders, 1998).

From the Late Sarmatian, the stress fieldward prolongation of the Pericarpathian line

formed during the following, latest Miocene epi- changed to a strike–slip configuration with NNE–

SSW-directed compression in the north to N–S-sode, in a strike–slip regime with N–S shortening

direction (Fig. 16B). Later, Pliocene south-vergent directed compression in the south. Widespreadleft-lateral shearing occurred along numerous E– out-of-sequence thrusting (Fig. 16C) enlarged the

S-ward off set of the mentioned thrusts and W-oriented faults in the north, and NW–SE-trend-

ing dextral transpressive structures in the south,accounts for the apparent continuity of the struc-

tures across the East Carpathians SE corner. accommodating an ESE-ward movement of the

intervening central sectors. These findings are com-

patible with the flexural modelling results, which

account for large-scale tearing and slab break-off 6. Overview and conclusions

mechanisms in the southern part of the East

Carpathians (Matenco et al., 1997b, Fig. 17B).The tectonic evolution of the foreland of the

East Carpathians can be described in terms of However, in accordance with other authors (e.g.

Sandulescu, 1984; Csontos, 1995) and diff erentlyLate Burdigalian to Sarmatian (Late Miocene)

shortening, Latest Sarmatian (Latest Miocene)– from Linzer (1996), we could find no evidence of

regional major strike–slip faults cross-cutting theEarly Meotian (Earliest Pliocene) strike–slip and

Pliocene shortening. external parts of the fold-and-thrust belt. Stress

and deformation stages similar to those presentedThe ENE–WSW-directed shortening acting in

Late Burdigalian to Sarmatian times was responsi- in this study have been documented in the South

Carpathians, particularly concerning the Lateble for the major nappe emplacement in the East


30/32


Burdigalian to Sarmatian and the Late Sarmatian tion no. 991101 of the Netherlands School of

Sedimentary Geology.phases (Matenco et al., 1997a). During the

Pliocene, the entire area was subject to an overall

NNW–SSE compressional stress regime, the eff ects

of which are observed mainly to the south, in the

bending area. References

The regional importance of Pliocene deforma-

tion is further demonstrated by recent paleostress Angelier, J., 1984. Tectonic analysis of fault slip data sets.J. Geophys. Res. 89, 5835–5848.work carried out in the bending area (Hyppolite

Angelier, J., 1989. From orientation to magnitudes in paleo-and Sandulescu, 1996; Morley, 1996) , in the south-stress determination using fault slip data. J. Struct. Geol.

ern part of the Moesian Platform (Bergerat and11, 37–50.

Pironkov, 1996) and with the present-day stress Angelier, J., 1994. Fault slip analysis and paleostress reconstruc-tion. In: Hancock, P.L. ( Ed.), Continental Deformation.field of the Carpatho-Pannonian region (Gerner,Pergamon Press, pp. 53–100.1992).

Angelier, J., Mechler, P., 1977. Sur une méthode graphique deMost of the Middle to Late Miocene evolutionrecherche des contraintes principales également utilisable en

of the East Carpathians and surrounding areastectonique et en seismologie: la méthode des dièdres droits.

was related to the westward subduction of the Bull. Soc. Géol. Fr. sér. 7e XIX (6 ), 1309–1318.Bancila, I., 1955. Paleogenul zonei mediane a flisului. Acad.distal parts of the East European, Scythian and

RPR Bull. St., Agron., Biol., Geol., Geogr. VII, 1201–1234,Moesian platforms and associated roughly

(in Romanian).E-vergent thrusting (Sandulescu, 1984; Royden, Bancila, I., 1958. Geologia Carpatilor Orientali. Ed. stiintifica,1988; Csontos, 1995). Processes and phenomena

Bucharest. 367 pp. ( in Romanian).taking place in more recent times are less agreed Bergerat, F., Pironkov, V., 1996. The Moesian Platform as a

key for understanding the geodynamical evolution of theupon. In particular, the role of the retreatingCarpatho-Balkan Alpine system. In: C.S.S. and B.E. (Eds.),subduction zone during Pliocene times is still beingStratigraphy and Evolution of Peri-Tethyan Platforms, Peri-debated (e.g. Linzer, 1996 and references citedtethys Memoir 3, 129–150.

therein). Our studies have demonstrated that theBotezatu, R., Calota, C., 1983. Asupra anomaliei cı̂mpului geo-

Latest Sarmatian strike–slip shearing was distrib- magnetic situata la nord-est de Suceava. Stud. Cerc. Geol.Geofiz. Geogr., Ser. Geofiz. 9, 3–22 (in Romanian).uted over large parts of the East Carpathians,

Cantini, P., Faggioni, O., Pinna, E., Soare, A., Stanicãa, D.,favouring a 40–50 km ESE-ward ‘escape’ of theStanicãa, M., 1991. Structure of the transition from the Her-central sectors, and that only limited deformationcynian lithosphere to the East European platform in Roma-

took place during the Pliocene. nia (Tornquist–Teisseyre zone). Atti del 10 ConvegnoAnnuale del Gruppo Nazionale di Geofisica della Terra

Solida, Roma, 6–8 Novembre, 601–613.

Ciulavu, D., 1999. Tertiary tectonics of the Transylvanian basin.

Ph.D. Thesis, Vrije Universiteit, Faculty of Earth Sciences,AcknowledgementsAmsterdam, 154 pp.

Csontos, L., 1995. Tertiary tectonic evolution of the Intra-Car-Part of this work was made possible by the pathian area: a review. Acta Vulcanol. 7, 1–13.

Delvaux, D., 1993. The TENSOR program for paleostressfinancial support of Shell Romania Explorationreconstruction: examples from the east and the BaikalB.V. and Free University, Amsterdam. Discussionsregion, Central Asia. Terra Nova 5, abstract suppl, 216.with D. Ciulavu, R. Huismans and C. Sanders

Delvaux, D., Moeys, R., Stapel, G., Petit, C., Levi, K.., Mirosh-have been inspiring. S. Cloetingh, C. Dinu and O.

nichenko, A., Ruzhich, V., San’kov, V., 1997. PaleostressDicea are thanked for useful ideas and permanent reconstruction and geodynamics of the Baikal region. Tecto-

nophysics 282, 1–4, 1–38.support. B. Sperner, D. Delvaux and E.Dicea, O., 1995. The structure and hydrocarbon geology of theWallbrecher are thanked for providing the software

Romanian East Carpathians border from seismic data.used for paleostress data processing. J.P. Brun, G.Petrol. Geosci. 1, 135–143.

Tari and L. Ratschbacher are thanked for con-Dicea, O., 1996. Tectonic setting and hydrocarbon habitat of

structive reviews, which have substantially the Romanian external Carpathians. In: Ziegler, P.A., Hor-vath, F. (Eds.), Peritethys Memoir 2: Structure and Pros-improved the quality of this work. This is publica-


31/32


pects of Alpine Basins and Forelands. In: Mémoires du tingh, S., C, D., 1997. Structural evolution of the Transylva-

nia basin (Romania): a sedimentary basin in the bend zoneMuseum national d’Histoire naturelle, Paris, pp. 403–425.

Dicea, O., Ali Mehmed, E., A, D., 1966. Contribution à l’étude of the Carpathians. Tectonophysics 272, 249–268.

Hyppolite, J.C., Sandulescu, M., 1996. Paleostress characteriza-de la tectonique de profondeur de la zone du flysch externe

et de la zone néogène du nord des Carpathes Orientales. tion of the ‘Wallachian’ phase in its type area, southeastern

Carpathians, Romania. Tectonophysics 263, 235–249.Rev. Roum. Géol., Géophys. Géogr., Sér. Géophys. 10,

177–182. Ionescu, N., 1994. Exploration history and hydrocarbon pros-

pects in Romania. In: Popescu, B. (Ed.), Hydrocarbon of Dumitrescu, I., 1952. Etude géologique de la région comprise

entre l’Oituz et la Coza. Ann. Com. Geol. XXIV, 195–270. Eastern Central Europe. Habitat, Exploration and Pro-

duction History. Springer-Verlag, pp. 220–250.Dupin, J.M., Sassi, W., Angelier, J., 1993. Homogenous stresshypothesis and actual fault slip: a distinct element analysis. Ionesi, L., 1971. Flisul paleogen din bazinul vaii Moldovei. Ed.

Acad. RSR, 200 pp. (in Romanian).J. Struct. Geol. 15 (8), 1033–1043.

Ellouz, N., Roca, E., 1994. Palinspastic reconstructions of the Joja, T., Mutihac, V., Muresan, M., 1968. Crystalline–Mesozoic

and Flysch Complexes of the East Carpathians (NorthernCarpathians and adjacent areas since the Cretaceous: a

quantitative approach. In: Roure, F. (Ed.), Peri-Tethyan Sector). In: Guide to Excursion 46 AC, Romania, Int. Geol.

Congr., XXIII Session, Prague, 5–63.Platforms. Editions Technip, Paris, pp. 51–78.

Ellouz, N., Roure, F., Sandulescu, M., Badescu, D., 1994. Bal- Linzer, H.G., 1996. Kinematics of retreating subduction along

the Carpathian arc, Romania. Geology 24, 167–170.anced cross sections in the eastern Carpathians (Romania):

a tool to quantify Neogene dynamics. In: Roure, F., Ellouz, Linzer, H.-G., Frisch, W., Zweigel, P., Girbacea, R., Hann,

H.-P., Moser, F., 1998. Kinematic evolution of the Roma-N., Shein, V.S., Skvortsov, I. (Eds.), Geodynamic Evolution

of Sedimentary Basins. Int. Symp. Proc., Moskow, 1992. nian Carpathains. Tectonophysics 297, 1–4, 133–156.

Marshak, S., 1988. Kinematics of orocline and arc formationTechnip, Paris, pp. 305–325.

Enescu, D., Pompilian, A., Bala, A., 1988. Distribution of the in thin-skinned orogens. Tectonics 7, 73–86.

Marshak, S., Wilkerson, M.S., 1992. Eff ect of overburden thick-seismic wave velocities in the lithosphere of some regions in

Romania. Rev. Roum. Géol. Géophys. Géogr., Sér. Géo- ness on thrust belt geometry and development. Tectonics

11, 560–566.phys. 32, 3–11.

Enescu, D., Danchiv, D., Bala, A., 1992. Lithosphere structure Matenco, L., 1991. Aplicatii ale metodelor sectiunilor balansate

in pinzele externe ale Carpatilor Orientali. Master Thesis,in Romania II. Thickness of Earth crust. Depth-dependent

propagation velocity curves for P and S waves. Stud. Cerc. University of Bucharest, Bucharest, 91 pp. (in Romanian).

Matenco, L., 1997. Tectonic evolution of the Outer RomanianGeol. Geofiz. Geogr., Ser. Geofiz. 30, 3–19.

Etchecopar, A., Vasseur, G., Daignieres, M., 1981. An inverse Carpathians: Constraints from kinematic analysis and flex-

ural modelling. Ph.D. Thesis, Vrije Universiteit, Faculty of problem in microtectonics for the determination of stress

tensors from fault striation analysis. J. Struct. Geol. 3 (1 ), Earth Sciences, Amsterdam, 160 pp.

Matenco, L., Schmid, S., 1999. Exhumation and uplift of the51–65.

Fodor, L., Csontos, L., Bada, G., Gyorfi, I., Benkovics, L., Danubian nappes system (South Carpathians) during the

Early Tertiary: inferences from kinematic and paleostress1996. Tertiary tectonic evolution of the Pannonian basin

system and neighboring orogens: a new synthesis of paleo- analysis at the Getic/ Danubian nappes contact. Tectono-physics, submitted.stress data. Mitteilungen der Gesellschaft der Geologie und

Bergbaustudenten in Osterreich, pp. 105–106. Matenco, L., Bertotti, G., Dinu, C., Cloetingh, S., 1997a. Terti-

ary tectonic evolution of the external South CarpathiansGerner, P., 1992. Recent stress field of Transdanubia, west Hun-

gary, ALCAPA: Geological Evolution of the Internal Alps, and the adjacent Moesian platform (Romania). Tectonics

16, 896–911.Carpathians and of the Pannonian Basin. Terra Abstr. 25.

Girbacea, R., Frisch, W., 1998. Slab in the wrong place: lower Matenco, L., Zoetemeijer, R., Cloetingh, S., Dinu, C., 1997b.

Lateral variations in mechanical properties of the Romanianlithospheric mantle delamination in the last stage of the

Eastern Carpathians subduction retreat. Geology 26 (7 ), external Carpathians: inferences of flexure and gravity mod-

elling. Tectonophysics 282, 147–166.611–614.

Guterch, A., Grad, M., Materzok, R., Perchuk, E., 1986. Deep Micu, M.C., 1990. Neogene geodynamic history of the Eastern

Carpathians. Geol. Carpathica 41 (1), 59–64.structure of the earth’s crust in the contact zone of the Paleo-

zoic and Precambrian platforms in Poland (Tornquist–Teis- Mocanu, V.I., Rãdulescu, F., 1994. Geophysical features of

the Romanian territory. In: Berza, T. (Ed.), Geologicalsere zone). Tectonophysics 128, 251–279.

Guterch, A., Grad, M., Janik, T., Materzok, R., Luosto, U., Evolution of the Alpine–Carpathian–Pannonian System,

ALCAPA II, Field Guidebook, Rom. J. Tect. Reg. Geol.,Yliniemi, J., Lück, E., Schulze, A., Förste, K., 1994. Crustal

structure of the transition zone between Precambrian and 17–36.

Morley, C.K., 1996. Models for relative motion of crustalVariscan Europe from new seismic data along LT-7 profile

(NW Poland and eastern Germany). C.R. Acad. Sci. Paris blocks within the Carpathian region, based on restorations

of the outer Carpathian thrust sheets. Tectonics 15, 885–904.319, 1489–1496.

Huismans, R.S., Bertotti, G., Ciulavu, D., Sanders, C., Cloe- Mrazec, L., Popescu-Voitesti, I., 1914. Contributions a la con-


32/32


naissance des nappes du Flysch Carpathique en Roumanie. Carpathians. Ph.D. Thesis, Vrije Universiteit, Amsterdam,

204 pp.Ann. Inst. Geol. Roum. V, 495–527.Sandulescu, M., 1984. Geotectonica României. Ed. Technica,Nieuwland, D.A., Walters, J.V., 1993. Geomechanics of the

Bucharest. 450 pp. ( in Romanian).South Furious field. An integrated approach towards solv-Sandulescu, M., 1988. Cenozoic Tectonic History of the Car-ing complex structural geological problems, including ana-

pathians. In: Royden, L.H., Horvath, F. (Eds.), The Pan-logue and finite-element modelling. Tectonophysics 226,nonian Basin, a Study in Basin Evolution, AAPG Memoir143–166.45, 17–25.

Pinna, E., Soare, A., Stanicãa, D., 1991. Transition zone of Sandulescu, M., 1992. Réunion extraordinaire de la Société

East Carpathians thrust belt, foredeep basin and East Euro-Géologique de France en Roumanie. Guide des Excursions.

pean Platform System. XVI EGS Gen. Ass. Ann. Geophys. Inst. Geol. Geofiz., Bucharest.(Suppl. to Vol. 9), 45. Sandulescu, M., Visarion, M., 1988. La structure des plate-

Pollard, D.D., Saltzer, S.D., Rubin, A.M., 1993. Stress inver- formes situées dans l’avant-pays et au-dessous des nappession methods: are they based on faulty assumptions? du flysch des Carpathes orientales. St. tehn. econ., Geofiz.J. Struct. Geol. 15 (8), 1045–1054. 15, 62–67.

Rabagia, T., Fülöp, A., 1994. Syntectonic sedimentation history Sandulescu, M., Krautner, H.G., Balintoni, I., Russo-San-in the Southern Carpathians foredeep. In: Berza, T. (Ed.), dulescu, D., Micu, M., 1981a. The structure of the EastGeological Evolution of the Alpine–Carpathian–Pannonian Carpathians (Moldavia–Maramures area). Carp.-Balc.

Assoc., XII Congr.System, ALCAPA II, Abstr. Vol., Rom. J. Tect. Reg.Sandulescu, M., Stefanescu, M., Butac, A., Patrut, I., Zahare-Geol., 48.

scu, P., 1981b. Genetical and structural relations betweenRabagia, T., Matenco, L., 1999. Tertiary tectonic and sedimen-flysch and molasse (The East Carpathians). Carp.-Balc.tological evolution of the South Carpathians foredeep: tec-Assoc., XII Congr.tonic versus eustatic control. Marine Petrol. Geol.

Schmid, S.M., Berza, T., Diaconescu, V., Froitzheim, N.,Rãdulescu, D.P., Cornea, I., Sandulescu, M., Constantinescu, Fuegenschuh, B., 1998. Orogen-parallel extension in the

P., Rãdulescu, F., Pompilian, A., 1976. Structure de laSouth Carpathians during the Paleogene. Tectonophysics

crôute terrestre en Roumanie. Essai d’interprétation des297, 209–228.

études séismiques profondes. Ann. Inst. Geol. Geofiz. 50,Simpson, C., Schmid, S.M.., 1983. An evaluation of criteria to

5–36. deduce the sense of movement in sheared rocks. Geol. Soc.Rãdulescu, F., 1988. Seismic models of the crustal structure in Am. Bull. 94, 1281–1288.

Romania. Rev. Roum. Géol. Géophys. Géogr., Sér. Géo- Spang, J.H., 1972. Numerical method for dynamic analysis of phys. 32, 13–17. calcite twin lamellae. Geol. Soc. Am. Bull. 83, 467–472.

Raileanu, V., Diaconescu, C., Rãdulescu, F., 1994. Characteris- Stefanescu, M., working group 1988. Geological cross sectionstics of Romanian lithosphere from deep seismic reflection at scale 1:200,000 A9-14. Inst. Geol. Geofiz., Bucharest.

Tari, G., Dicea, O., Faulkerson, J., Georgiev, G., Popov, S.,profiling. Tectonophysics 239, 165–185.Stefanescu, M., Weir, G., 1997. Cimmerian and Alpine stra-Ratschbacher, L., Linzer, H.G., Moser, F., Strusievicz, R.O.,tigraphy and structural evolution of the Moesian platformBedelean, H., Har, N., Mogos, P.A., 1993. Cretaceous to(Romania/ Bulgaria). In: Robinson, A.G. (Ed.), Regional

Miocene thrusting and wrenching along the central South and petroleum geology of the Black Sea and surroundingCarpathians due to a corner eff ect during collision and oro-regions, AAPG Memoir 68, 63–90.cline formation. Tectonics 12, 855–873.

Turner, F.J., 1962. ‘Compression’ and ‘tension’ axes deducedRögl, F., 1996. Stratigraphic correlation of Paratethys O

Documents

Matenco-bertotti-2000