Tertiary Tectonic and Sedimentological Evolution of the South Carpathians Foredeep: Tectonic Vs Eustatic Control

Marine and Petroleum Geology 16 (1999) 719±740

Tertiary tectonic and sedimentological evolution of the South Carpathians foredeep: tectonic vs eustatic control

T. RabaÆ gia a,*,1, L. Mat° enco b

aProspect° iuni S.A., Hydrocarbon Division, 20 Coralilor str., Bucharest, 1, Romania bBucharest University, Faculty of Geology and Geophysics, 6 Traian Vuia str., sect. 1, 70139, Bucharest, Romania Received 25 October 1998; received in revised form 2 August 1999; accepted 6 August 1999

Abstract

A detailed seismic sequence stratigraphy study based on a dense network of seismic pro®les is integrated with structural observations from interpreted geological sections to derive a tectonic and sedimentological model for the Miocene±Pliocene evolution of the South Carpathians foredeep (Getic Depression). Following Paleogene and older orogenic phases, the ®rst tectonic event which aected the studied area was characterised by Early Miocene large scale extension to transtension which is responsible for the opening of the Getic Depression as a dextral pull-apart basin. Further Middle Miocene contraction caused WNW±ESE oriented thrusts and associated piggy-back basins. The last tectonic episode recognised in the studied area relates to general transpressive deformations during the Late Miocene±Early Pliocene interval, a ®rst NW±SE oriented dextral episode is followed by second N±S sinistral deformations. The detailed sequence stratigraphy study allows for the de®nition of the dominant tectonic control of the sedimentary sequences in foreland basins. A eustatic control may be associated, but has a clear subordinated character. # 1999 Elsevier Science Ltd. All rights reserved.

Keywords: South Carpathians; Sequence stratigraphy; Tectonics; Eustasy

1. Introduction sional deformations, the entire system being buried by 1±2 km of ¯at-lying Pliocene sediments, slightly The South Carpathians foredeep, named the Getic deformed in the last, late Pliocene tectonic event Depression or the South Subcarpathians (SaÆ ndulescu, (Dicea, 1996; Mat° enco, Bertotti, Dinu & Cloetingh, 1984), represents a sedimentary basin developed at the 1997; RaÆ baÆ gia & FuÈ lop, 1994). contact between the South Carpathians nappe pile and Previous studies of the eustatic and tectonic control the Moesian Platform (SaÆ ndulescu, 1984) (Fig. 1). The on the development of the sedimentary bodies in active 50±100 km wide basin comprises more than 6 km of tectonic basins (Crumeyrolle, Rubino & Clauzon, Uppermost Cretaceous to Tertiary sediments deposited 1991; Leckie & Smith, 1992; Prosser, 1993; Robertson, in a polyphase tectonic regime. Following a general Eaton, Follows & McCallum, 1991) have demon- tectonic scheme, the evolution of the Getic Depression strated the importance of the sequence analysis in was characterised by Paleogene to Lower Early revealing the detailed architecture of the sedimentary Miocene extension/transtension followed by large scale basins. Several uncertainties arise in de®ning the in¯u- Middle to late Miocene contractional to transpres- ence of tectonic in respect to eustatic control in active tectonic areas, especially in foreland basin settings (Robertson et al., 1991; Vail et al., 1977). * Corresponding author. Tel.: +40-1-3110922; fax: +40-1- Previous studies of the South Carpathians generally 3111168. focused on the northern nappe pile (Berza & E-mail address: [email protected] (T. RabaÆ gia) 1 Present address: Schlumberger Logelco, Romanian Branch, Hotel DraÆ gaÆ nescu, 1988; Codarcea, 1940; Mat° enco et al., Diplomat 106, 13-17 Sevastopol str., sect. 1, Bucharest, Romania. 1997; Murgoci, 1905; Ratschbacher et al., 1993).

0264-8172/99/$20.00 # 1999 Elsevier Science Ltd. All rights reserved. PII: S0264-8172(99)00045-8 720 .RbÆi,L Mat L. RabaÆgia, T. ° no/Mrn n erlu elg 6(99 719±740 (1999) 16 Geology Petroleum and Marine / enco

Fig. 1. Geological structural map of the external part of the South Carpathians. Compiled from geological maps 1:200.000, 1:50.000, published by the Geological Institute of Romania and results of this paper structural work. Thick lines, 1±14, indicate the position of pro®les in Figs. 5±8. SI to SV indicates the position of Figs. 9±13, respectively. Inset indicate the position of the structural map detailed in Fig. 4. T. RabaÆgia, L. Mat° enco / Marine and Petroleum Geology 16 (1999) 719±740 721

Fig. 2. General time correlation table and stratigraphyic column for the Tertiary deposits and sketch of the main tectonic events (modi®ed after Mattenco & Schmid, 1999). Correlation with Central and Eastern Parathethys for the Oligocene and Miocene and Pliocene ages after RoÈ gl (1996). Hatched areas represent the ages used in this study. Note especially the dierences at the Miocene/Pliocene boundary between the ages used in the present study and the standard Tethys scale. Thick light grey and dark grey arrows represent an attempt to de®ne a foreland-breaking sequence for the extensional deformation and for the contractional deformation respectively. SSQ represent the seismic sequences de®ned in the present study. General deformation patterns represent results of this paper and correlation with Ratschbacher et al. (1993), Mat° enco (1997), Schmid et al. (1998) and Mat° enco and Schmid (1999).

However, few studies have taken into account the is still to be pursued (e.g., Mat° enco, 1997; RaÆ baÆ gia & detailed analysis of the foredeep sedimentary architec- FuÈ lop, 1994) (Fig. 1). ture as a whole (Dicea, 1996; Motas° , 1983), while the The Getic Depression is analysed in this paper detailed kinematic and tectonic evolution of the basin through a dense network of roughly 3500 km of seis- 722 T. RabaÆgia, L. Mat° enco / Marine and Petroleum Geology 16 (1999) 719±740

as a result of the Late Cretaceous ``Laramian'' deformations, namely the Dacidic molasse (SaÆ ndulescu, 1984). A thick coarse-grained clastic succession was deposited on the inner basement formed by the Getic, Severin and the Danubian nappes, and on the Mesozoic carbonates and Paleozoic series of the Moesian platform (Dicea, 1996). An Uppermost Cretaceous (Campanian±Maastrictian) succession can be observed at surface in the east, as well as at depth, westward, close to the northern basin border. Thick (1000±1500 m) coarse-grained clastic deposits are transgressively covering the northern border in the eastern region (Szasz, 1975). The Paleogene is characterised by a thick succession (roughly 5000 m in the Fig. 3. 1D basement subsidence evolution based on backstripping northern parts), transgressively covering the techniques (Steckler & Watts, 1978; Watts, Karner & Steckler, 1982). Cretaceous deposits in the NE areas (Jipa, 1980, 1982, 1=Ticleni, 2=Bibesti, 3=Bulbuceni, 4=Bustuchini, 5=Alunu 1984), onlapping southward the top-Cretaceous uncon- representative wells in various oil®elds (for location see Fig. 4). Note that the curves represent the basement subsidence, i.e. no isostatic formity of the Moesian platform (Dicea, 1996) and compensation was performed to derive tectonic subsidence curves, recording up to 2500 m basement subsidence in the due to the ¯exural behaviour of the foreland (Moesian) platform in western parts of the Getic Depression (Fig. 3). the front and below the foredeep (Mat° enco, 1997). Note the signi®- The Miocene sedimentary cycle (Fig. 2) is mainly cant Eocene subsidence in the Ticleni structure, the Early composed by clastic deposits, the basal coarse sedi- Burdigalian subsidence related to the onset of the extension and the large Sarmatian subsidence in the frontal part of the Pericarpathian ments being gradually replaced upward by ®ner sedi- thrust (Bibesti, Bulbuceni). ments. A regional unconformity, the ``Paleogene morphology'' (Paraschiv, 1975), marks the beginning of this cycle. The Lower Miocene is characterised by mic lines, distributed both along the E±W strike of the major subsidence (Fig. 3), accommodating up to 2000 basin and on the N±S cross sections. The average dis- thick conglomerates (Dicea, 1996), followed by tance between the lines is about 5 km, their calibration roughly 500 m of ®ner marine deposits (Fig. 2). Upper being made with 65 correlation wells. The high data Burdigalian sediments are deposited above a regional density has allowed the de®nition of a detailed local unconformity, observed both on seismic lines and on seismic/sequence stratigraphy, correlation of the outcrops, marking the transition to an evaporitic or sequences being possible directly between the lines. lacustrine episode. Further Badenian deposits are Further conclusions enabled a detailed Miocene tec- characterised by tus, marine marls and salt deposits. tonic and sedimentary model, focused mainly on the The top of the Miocene sedimentary cycle is de®ned sedimentary response of the tectonic deformations by the Lower to Middle Sarmatian (Upper Miocene in within the South Carpathians foredeep. These ®ndings Paratethys time scale) siliciclastic deposits, which de- are important for the quantitative assessment of the ®ne the most important syntectonic sediments. role of the structural and eustatic control, providing The third sedimentary cycle (Upper Sarmatian± further constraints on the mode of tectonic and sedi- Pliocene ) (Fig. 2) is mainly characterised by up to mentary evolution. The latter has major implications 2000 m clastic deposits covering the deformed part of for the processes controlling the formation and archi- the foredeep. The various basins separated by the tecture of sedimentary basins along the external Miocene tectonic activity were ®lled during the Late Romanian Carpathians. Miocene to Pliocene times, maximum thickness being observed in the foreland of the frontal (Pericarpathian) thrust (Mat° enco, 1997; RaÆ baÆ gia & FuÈ lop, 1994), where 2. Geological background large subsidence values are recorded especially during the Late Miocene (Fig. 3). At the same time, signi®- The Tertiary evolution of the Getic Depression is cant uplift takes place in the inner South Carpathians, mainly characterised by major variations in sedimen- as suggested by ®ssion track data (Bojar, Neubauer & tary and structural patterns. A roughly S-ward thin- Fritz, 1998; Sanders, 1998). ning clastic wedge is observed, three main sedimentary Most of the accepted plate tectonic models (e.g. cycles being de®ned in connection with the tectonic ac- Csontos, 1995; Ratschbacher et al., 1993; Royden & tivity (Dicea, 1996; Mat° enco, 1997; Motas° , 1983). BaÂ ldi, 1988; SaÆ ndulescu, 1984) assume that the A®rstUppermost Cretaceous±Paleogene cycle (Fig. Tertiary tectonic evolution of the South Carpathians 2) is characterised by molasse type sediments deposited foredeep represent the result of the complex interaction T. RabaÆgia, L. Mat° enco / Marine and Petroleum Geology 16 (1999) 719±740 723

Fig. 4. Detailed structural map of the central and western area of the Getic Depression. Note the large scale normal faults truncated by later transpressional transcurrent movements. Description in the text, location in Fig. 1. between the movements of the Rhodopian fragment tral transcurrent movements during the late Miocene (Burch®el, 1976) to the N and NW and the Moesian (Mat° enco, 1997). platform towards the S and SW (Mat° enco et al., 1997). According to SaÆ ndulescu (1984), the South Carpathians foredeep becomes tectonically active only in Sarmatian times (Moldavides deformation), when 3. Seismic analysis the Subcarpathian nappe was thrusted southward on top of the Moesian platform, along a sole thrust, The South Carpathians foredeep has been recently whose tip line is de®ned as the Pericarpathian linea- been investigated in detail through a large number of ment. According to more recent interpretations (e.g., seismic studies and wells performed for the petroleum Ratschbacher et al., 1993; Csontos, 1995), the Moesian industry, the Getic Depression being a large oil and platform acted during the Alpine orogeny as a rigid gas Miocene basin (see also Dicea, 1996). The dense ``corner'', imposing late Cretaceous to Paleogene dex- seismic network and the correlation wells enabled a tral wrenching in the South Carpathians and causing detailed seismic sequence analysis, focused especially E±W contraction and subsidence in its northern part. on the Miocene deposits. This further allowed the de®- The latter would be responsible for the large amount nition of a kinematic, structural and sedimentological of Uppermost Cretaceous±Paleogene sediments depos- model, integrated in the currently available plate tec- ited in the area. Other authors (e.g., Mat° enco et al., tonic scenarios. Further discussion will take into 1997) assume that the Paleogene±Early Miocene account 14 regional geological cross sections (Fig. 4) period is characterised by large scale extension to (Figs. 5±8), the major structures being detailed in ®ve transtension, due to the NE-ward movement of the local seismic lines (Figs. 9±13). In the western±central Rhodopian fragment. Despite the classical images, this part of the Getic Depression the high density of the model assume a further NE±SW Late Burdigalian con- seismic lines made possible the direct correlation of the traction and NW±SE to N±S oriented large scale dex- seismic sequences (Fig. 4), while in the eastern part of 724 .RbÆi,L Mat L. RabaÆgia, T. ° no/Mrn n erlu elg 6(99 719±740 (1999) 16 Geology Petroleum and Marine / enco

Fig. 5. Interpreted seismic pro®les 1±4, across the western area of the Getic Depression. 1±14 represent seismic sequences for the Miocene±Lower Pliocene deposits. Earlier sequences have not been interpreted along the seismic pro®les. Thick dashed lines represent the supposed eroded traces of the normal faults. Location in Fig. 1. (a) Interpreted pro®le 1; (b) interpreted pro®le 2; (c) interpreted pro®le 3; (d) interpreted pro®le 4. .RbÆi,L Mat L. RabaÆgia, T. ° no/Mrn n erlu elg 6(99 719±740 (1999) 16 Geology Petroleum and Marine / enco

Fig. 6. Interpreted seismic pro®les 5±8, across the central±western area (a±c) and central±eastern area (d) of the Getic Depression. Figure conventions as in Fig. 4. (a) Interpreted pro®le 5; (b) interpreted pro®le 6; (c) interpreted pro®le 7; (d) interpreted pro®le 8. 725 726 .RbÆi,L Mat L. RabaÆgia, T. ° no/Mrn n erlu elg 6(99 719±740 (1999) 16 Geology Petroleum and Marine / enco

Fig. 7. Interpreted seismic pro®les 8±12, across the central-eastern area of the Getic Depression. Figure conventions as in Fig. 4. (a) Interpreted pro®le 9; (b) interpreted pro®le 10; (c) interpreted pro®le 11; (d) interpreted pro®le 12. T. RabaÆgia, L. Mat° enco / Marine and Petroleum Geology 16 (1999) 719±740 727

Fig. 8. Interpreted seismic pro®les 13±14, across the eastern area of the Getic Depression. No separation and correlation of the seismic sequences has been performed due to the low number of seismic data. Figure conventions as in Fig. 4. (a) Interpreted pro®le 13; (b) interpreted pro®le 14. the area the correlation was made only on the basis of character of the normal faults is observed through the the well data (Fig. 1). rotation of the re¯ectors and strata (e.g., Fig. 6). Further sedimentological discussion will take into The second WNW±ESE trending normal system is account recently developed seismic-sequence terminol- located roughly in the middle of the basin and is devel- ogy in extensional basins (e.g., Prosser, 1993). oped only in the eastern areas (Figs. 4, 7 and 8). Here, According to this terminology, the evolution of these the normal faults de®ne an important WNW±WSE basins could be divided into a ®rst rift initiation, fol- trending pre-Miocene tilted block, which divide two lowed by rift-climax and post-rift system tracts. This major sub-basins. The largest 1.5 to 2 s oset along approach enables the de®nition of a high resolution these faults is observed along the southern sub-basin. seismic sequence stratigraphy in the extensional A major normal fault with oset greater than 2000 m deformed units of the Getic Depression. develops at the same time with narrowing of the extensional basin (Fig. 7d). 3.1. Pre-Middle Burdigalian deformations and sequence A large scale transfer zone is observed between the analysis two systems (Fig. 4). An increased number of ENE± WSW to E±W oriented normal faults with decreased Within the pre-Miocene deposits, the major struc- osets (Figs. 6 and 7) de®ne the transfer of the exten- tural features relate to normal faulting, two major sys- sional deformation from west to east and also from tems with dierent strike being de®ned in direct the northern basin border southward. relationship with their position within the basin (Fig. Because of the locally unclear seismic sections, one 4). Both systems are locally inverted in later Miocene can interpret part of the normal faults footwall in the deformations, the faults and the pre-Miocene re¯ectors northern part of the basin, as south to SW-ward re- being truncated by a regional unconformity. lated thrusting. However this local interpretation can- The ®rst NE±SW trending normal system is located not be laterally prolonged in most of the other places near the northern basin border and is developed in the where the normal faulting is not ubiquitous. In ad- western part of the basin, individual faults having over dition, this interpretation cannot be conciliated with 2500 m osets (Figs. 4 and 5). An associated antithetic coeval normal faulting taking place along similar 728 T. RabaÆgia, L. Mat° enco / Marine and Petroleum Geology 16 (1999) 719±740

Fig. 9. Seismic pro®le I and interpretation along the western area of the Getic Depression. Depth in TWT seconds. Discussion in the text, location of pro®le in Fig. 1.

oriented NNE±SSW normal faults, developed in the the westernmost areas, where later Miocene defor- southern part of the basin. mations are reduced. During the Early Miocene times, the tectonic ac- A representative pro®le can be observed in Fig. 9, tivity can be closely followed in the sedimentary record where the seismic sequences are developed in close on the basis of the separation and correlation of the connection with the adjacent normal fault. In this sec- seismic sequences (sequences 1±5, Fig. 5), especially in tion, the ®rst analysed seismic facies unit (sequence 2) T. RabaÆgia, L. Mat° enco / Marine and Petroleum Geology 16 (1999) 719±740 729

Fig. 10. Seismic pro®le II and interpretation along the central±western area of the Getic Depression. Depth in meters. Discussion in the text, location in Fig. 1. has an wedge shape and is characterised by chaotic/ sedimentary source for this early rift-climax system subparallel re¯ectors, truncations and onlap towards tract, dominated by mass-transport processes (see also the hanging-wall. These characters indicate typical rift- Prosser, 1993), as demonstrated by the direction of initiation features, with lateral, probably subaerial, progradation and the normal fault footwall erosion. sedimentary transport, as suggested by the total lack The following seismic sequence (5, Fig. 9) develops of marine fauna and the coarse facies observed in the over a new unconformity, with mound-shaped bodies neighbouring deep wells. The end of this sequence is with lateral onlap, local channels and levee, interpreted marked by truncations along the downlap surface, as axial turbidites. This seismic sequence represents a which may be related to the antithetic character of the mid-rift climax system tract, the basin becoming normal fault. The next sequences (3 and 4, Fig. 9) are starved and open marine. This observation is in con- characterised by prograding bodies downlapping cordance with the ®rst occurrence of a marine fauna towards the hanging-wall, having a chaotic seismic during the Middle Burdigalian. The next re¯ector facies near the main fault, which may be interpreted as package has a parallel con®guration with onlap toward a the rift-climax system tract. This sequence is built-up the fault footwall (sequences 7±10, Fig. 9), draping the by footwall fans, and records the maximum displace- Lower Miocene sediments. The coastal onlap advances ment along the main normal fault. Due to this large and oversteps the footwall source area (late rift climax displacement, the fault footwall becomes the main system tract and post rift system tract), revealing a 730 T. RabaÆgia, L. Mat° enco / Marine and Petroleum Geology 16 (1999) 719±740

Fig. 11. Seismic pro®le III and interpretation along the E±W strike of the central area of the Getic Depression. Depth in TWT seconds. Location in Fig. 1. Note the development of large scale dextral Jiu Fault (JF) and Motru Fault (MF) up to 6 s TWT at depth. Note the strike (sub)horizontal Late Burdigalian±Badenian thrust faults, truncated by later large scale Sarmatian strike-slips. A reactivated Early Burdigalian normal fault can be observed in the western area. decreased tectonic subsidence and the beginning of the ®ll (sequence 5a, Fig. 6d), and surface timing indi- basin ®ll. cators (Lower Sarmatian sediments unconformable Further to the east, in the area of changing strike of covering Burdigalian thrusted deposits in the Sohodol the normal faults from NE±SW to WSW±ENE (Figs. valley area, Mat° enco, 1997). 5d±6b), the tectonic subsidence starts earlier, observed In the central±eastern area (Figs. 1, 4, 6d, 7 and 8), in sequence 1 Ð rift initiation Ð followed by sequence the Pre-Miocene transtensional structures are inverted 2 Ð rift climax. leading to the formation of an imbricated thrust system. The piggy-back basins are ®lled with Badenian 3.2. Late Burdigalian±Badenian deformations salt deposits (sequence 5a). A coeval uplift of the Pre- Miocene blocks takes place, as demonstrated by the Starting with the Late Burdigalian, the major struc- re¯ectors truncation in the hanging-wall of the thrust tural feature is the presence of reverse faults, which sheets (Fig. 7c and d). Local dierences in the thrust structurally de®ne various uplifted areas along the characteristics can be related to these inherited pre- foredeep. The deformation is mainly characterised by Miocene blocks, their presence in the eastern areas the formation of an imbricated thrust system with WNW±ESE strike, associated with the development of favouring the thrusting migration towards the fore- local piggy-back basins (Fig. 4). The pre-Miocene± land. Lower Burdigalian basin ®ll was thus inverted and Westward, the thrusting amplitude decreases, being thrusted towards the Moesian platform. The age of con®ned only to small-scale thrusting and folding (e.g., this tectonic event is constrained by the truncation of Ticleni Bilteni structures, Figs. 6a and 10). Most of the the Upper Burdigalian sediments (e.g., sequences 4, 5, Middle Miocene thrusts were reactivated by later Late the Ticleni±Bilteni structure, Figs. 6 and 10), the syme- Miocene NW±SE dextral transpressive deformations trical onlapping of the Sarmatian deposits (sequence 7, (see further), which makes dicult to separate all the Fig. 10), and the Badenian age of the piggy-back basin Middle Miocene thrusts. .RbÆi,L Mat L. RabaÆgia, T. ° no/Mrn n erlu elg 6(99 719±740 (1999) 16 Geology Petroleum and Marine / enco

Fig. 12. Seismic pro®le IV and interpretation along the central±eastern area of the Getic Depression. Depth in TWT seconds. Discussion in the text, location in Fig. 1. Note the reactivation of the Early Burdigalian extensional/transtensional structures by later Late Burdigalian thrust faults. 731 732 T. RabaÆgia, L. Mat° enco / Marine and Petroleum Geology 16 (1999) 719±740

Fig. 13. Seismic pro®le V and interpretation along the eastern area of the Getic Depression. Depth in TWT seconds. Discussion in the text, location in Fig. 1.

3.3. Sarmatian±Early Pliocene deformations and the sin-extensional sediments being truncated by NW±SE to N±S trending sub-vertical reverse faults or- The Sarmatian deformations represent the most im- ganised in positive ¯ower structures. The ®rst dextral portant tectonic event recorded in the Getic moment has maximum oset during the sequences 7, 8 Depression foredeep (Dicea 1995, 1996; SaÆ ndulescu, (Early to Middle Sarmatian), as demonstrated by the 1988; Tari, HorvaÂ th & Rumpler, 1992). Deformation truncation and onlapping of the internal re¯ectors is mainly characterised by the formation of transpres- (e.g., Fig. 5b and c). The second sinistral moment is sional strike-slip duplexes and ¯ower structures (e.g., characterised by maximum activity at the top of Figs. 10±12) associated with the frontal thrusting of sequence 9 (late Sarmatian), where small-scale struc- the foredeep upon the Moesian platform (e.g., Fig. 8). tural uplifts develop on N±S trending strike-slip faults Although deformation was continuous during the without re¯ector truncation, but with symmetrical Sarmatian±Early Meotian, two peaks with dierent onlap at the base of sequence 10 (e.g., Fig. 5b). characteristics can be de®ned on the basis of structural Locally, activity along these faults could be further characteristics and deformation ages. An Early to continued during the Early Pliocene (Fig. 5d). Middle Sarmatian moment is characterised by dextral Further to the east (Fig. 6a±c), the Sarmatian defor- transpressional NW±SE trending faults, shortly pre- mation increases, the largest transpressional structures dating a second Late Sarmatian±Early Meotian in of the Getic foredeep being interpreted in the sub- moment, characterised by sinistral N±S trending faults surface. NW±SE trending dextral faults are organised (Figs. 1 and 4) (see also Mat° enco et al., 1997; in transpressional strike-slip duplexes, inverting the Ratschbacher et al., 1993). pre-existing Late Burdigalian±Badenian thrusts. A Four major zones can be observed in the foredeep, good example is oered by the Ticleni±Bilteni uplift on the basis of the deformation character. (Figs. 10 and 11), where the Late Burdigalian± In the western area (Figs. 4 and 5) the Sarmatian de- Badenian structures are truncated by a large scale posi- formations are reduced, the pre-existing normal faults tive ¯ower structure with NW±SE strike, with typical T. RabaÆgia, L. Mat° enco / Marine and Petroleum Geology 16 (1999) 719±740 733 vertical oset in the order of 0.5 s. The Early to Unconformities were de®ned using the re¯ector termin- Middle Sarmatian age is proven by the truncation of ations and the internal geometry. sequence 7 and the symmetrical onlapping of sequence The seismic sequence development mirrors the lat- 8 (see also Fig. 6b and c). In the same area, the second eral variations in the structural style of the Getic Sarmatian deformation (the Late Sarmatian±Early Depression. Three major areas can be de®ned on the Pliocene) is characterised by N±S trending sinistral basis of the seismic sequences characteristics. transpressional ¯ower structures, their activity being In the western Getic Depression (west of Jiu valley, recorded from the end of sequence 8 (e.g., Colibasi± Figs. 4, 5 and 9) Middle Miocene to Pliocene re¯ectors West, Fig. 6c) up to the end of sequence 14 (e.g., have a parallel con®guration and onlap over the exten- Bibesti±Early Upper Pliocene, Fig. 6c). sional blocks. Clinoforms develop during the Lower Eastward, the structural style of the Sarmatian tec- Pliocene, controlled by the extensional blocks position, tonic event changes to an E±W trending imbricated earlier prograding bodies being observed only in the thrust system formed in a strike-slip regime with N±S hinterland of these blocks. All the seven regional seis- compression direction (see also Mat° enco et al., 1997). mic sequences (6±14) are well visible in the seismic Activation of this system is related to the inversion of pro®les, having a clear dierent sedimentological sig- pre-existing E±W trending Lower Miocene transten- ni®cance. Sequence 6 (Upper Miocene Ð Fig. 5b and c) sional structures (Figs. 4±7). The imbricated thrust sys- with a mounded shape, characterised by chaotic tem is composed of medium to high angle reverse seismic facies, is interpreted as a LSST-bfc/turbiditic faults, which truncate deposits as young as the Lower bodies (Vail et al., 1977). Sequence 7 records also the Sarmatian (sequence 7). The whole system is thrusted LSST period with parallel con®guration and coastal over the Paleogene±Lower Miocene deposits of the onlapping surfaces, but without prograding complex Moesian Platform. Locally, the thrust system is con- features. At sequence 7 top, local small prograding ®ned to the area south of the large scale extensional bodies can be observed symmetrically to the positive block formed during previous Lower Early Miocene ¯ower structures (Fig. 5b and c). Sequences 8 and 9 extension (Fig. 7c and d). The NW±SE trending trans- start with onlapping surfaces (Figs. 5a, b and 9), show pressional structures are organised in positive ¯ower a base level drop and represent LSST intervals, with structures (Vladimiri, Piscu Stejarului, Bustuchini-East, non-correlable turbiditic bodies. However, NW-ward ZaÆ treni, DraÆ ganu, Fig. 4) with maximum uplift during of the extensional blocks, HSST prograding bodies can sequence 8 and developed up to sequence 9 be observed during the same time span (Figs. 5a, b (Uppermost Miocene). and 9). Seismic sequences 10 and 12 (Lower Pliocene) The easternmost area of the Getic Depression (Figs. have unconformity relationships with sequence 9, par- 1 and 8) is dominated by the imbricated thrust system, allel and prograding re¯ectors and form a single deformation generally increasing eastward. The depositional sequence. The ®nal seismic sequence (14), Miocene basin ®ll was thrust southward over the which represent a new one (Vail et al., 1977), has the Sarmatian of the Moesian Platform for a larger dis- same parallel and prograding re¯ectors and basal tance than in the western areas, de®ning along the onlap surfaces. frontal sole thrust, the Pericarpathian fault. In the central±eastern Getic Depression (Figs. 6a±c Deformation begins also during the same Sarmatian, and 10) important changes take place at sequence 7 being characterised by local piggy-back basins (Fig. and 8 level. In this area, with a higher degree of defor- 8a), and is prolonged up to the Middle Pliocene (Fig. mation, an increased number of local unconformities 8b). Locally, along the Early Miocene extensional (onlap and truncation) de®ne new seismic sequences Ð structures both Sarmatian and Meotian are truncated 7a, 7b, 8a, 8b, 8c Ð, equivalent of the western 7 and 8 along the uplifted blocks. The large scale thrusting is seismic ones. Towards the foreland, the separation of associated with local ¯ower structures (e.g., Botes° ti, these sequences is no longer valid, except the original Fig. 8b). unconformity between sequences 7 and 8. In the eastern Getic Depression (east of pro®le 8, 3.4. Middle Miocene±Pliocene sequence analysis Figs. 6d, 7, 8 and 12), the activity of the imbricated thrust system is recorded slightly earlier, at sequence 5 The seismic sequence analysis of the Middle level. This sequence is further separated in pre/syn- Miocene±Lower Pliocene deposits has revealed a clear compressional in®ll by the development of the piggy- post-rift sedimentological character, being controlled back basins. Increased tectonic activity vs the western by the evolution of compressional/transpressional regions is recorded at sequences 7 and 8 level, where structures and by sea-level changes. Major character- onlapping unconformities surrounding the active tec- istics of the basin are linked with the development of tonic areas are associated with new downlapping sur- eight major correlable seismic sequences (e.g., 7±14, faces (sequence 8b) and turbiditic bodies (ssq. 8b'). Fig. 9) with major sedimentological constraints. Along the easternmost analysed pro®les 11 and 12 734 T. RabaÆgia, L. Mat° enco / Marine and Petroleum Geology 16 (1999) 719±740

Fig. 14. Lower Burdigalian isopach map obtained through direct interpolation of the Lower Burdigalian vertical thickness measured in the interpreted seismic lines. Values are TWT seconds, fault osets were neglected due to direct interpolation procedure. Note the large depocenter in the central±western part of the basin and the development of several sub-basins in the eastern areas.

(Fig. 8), an increase in the southern thrusting defor- tonic sediments reaching their maximum thickness in mation is linked with new local unconformities devel- the intermediate area (Figs. 4 and 14). The width of oped up to sequence 14. A good example is oered by the extensional basin is gradually decreasing towards basal symmetrical onlap around the RomaÃnesti uplift. the eastern and western basin borders, where larger The northern area is characterised by symmetrical osets can be recognised along individual normal onlap relationship in respect to the basin axis (Fig. faults (Fig. 14). An associated antithetic character of 7c). the normal faults can be de®ned on the basis of footwall strata rotations. The exact age of the transtensional deformation is still to be worked out due to 4. Structural and sedimentological model of the uncertainties in dating the ®rst syn-rift sequences. Miocene±Pliocene evolution of the Getic Depression However, this age is constrained by the dated Oligocene deposits in the footwall of the normal faults The Getic Depression is the result of a complex sedi- and by the well dated Middle Burdigalian age of the mentologic and tectonic evolution, four major episodes second syntectonic sequences (rift climax Ð sequences being recognised during the Tertiary, namely the Early 3 and 4). Miocene transtension, the Middle Miocene positive During this time span, sedimentation has a clear inversion, the late Miocene (Intra-Sarmatian) right-lat- syn-tectonic character with high subsidence rate visible eral transpression and the Early Pliocene sinistral at sequences 1±5 level. The sedimentation has a pro- strike-slip. nounced tectonic control, deposition being similar with the Prosser (1993) model, which assumes a low eustatic 4.1. Early Miocene transtension and syn-rift control. This interpretation is supported by the lateral sedimentation variation of the pre-rift, rift initiation and rift climax system tracts which closely follow the tectonic control During this timespan, the Getic Depression starts its along the normal faults. The lateral variation can be distinct tectonic and sedimentological evolution. Large demonstrated along the interpreted seismic pro®les by scale transtensional structures can be observed along the time migration of the hummocky seismic con®gur- the whole basin, being mainly characterised by steep ation of the rift-initiation, and of the downlapping sur- normal faults (Fig. 17). Faults strike changes from faces of the rift-climax system tracts. As a consequence NE±SW in the west to WNW±ESE in the east, syntec- the seismic sequences 1, 2, 3, 4, 5 represent tectonic T. RabaÆgia, L. Mat° enco / Marine and Petroleum Geology 16 (1999) 719±740 735

Fig. 15. Balanced cross section in the western part of the Getic Depression (after Mat° enco, 1997), using the method for zones with multiple deformations (Woodward, Boyer & Suppe, 1989). Note that only the Pliocene deformations were restored. Earlier deformations were not restored due to transcurrent movements (plane-strain assumption, e.g., Woodward et al., 1989). system tracts (Prosser, 1993) and their boundaries rep- strike-slip system, which can be closely followed along resent tectonic control unconformities. the whole western part of the studied area. According to earlier interpretations (e.g., Stefanescu The opening of an extensional basin in the western & working group, 1988), the uplifted position of the part of the Getic Depression is supported by geophysi- Early Miocene normal faults footwall was related to cal and tectonic modelling arguments. The anomalous thrusting, in direct connection to the Late Miocene ac- shape of the Bouguer anomaly in the South tivity of the Pericarpathian thrust, which according to Carpathians, whose minimum (135 mgals) is placed these authors should westward follow the bending of in the middle of the foredeep and shows the largest the South Carpathians, in a position similar to the density contrast for the Romanian Carpathians (e.g., normal faults de®ned in the map view in the western- Sza®an, 1999), the large foredeep heat ¯ow anomaly, most part of the Getic Depression. Southward, the as well as the thermally young lithosphere with low eective elastic thickness (Mat° enco, 1997) indicate a thrusting along the Pericarpathian sole fault would be large amount of sediments deposited during and after transferred to dextral displacement along the Timok/ a relative young stretching tectonic episode. Cerna fault system (Royden & BaÂ ldi, 1988; SaÆ ndulescu, 1988). According to these authors, the 4.2. Middle Miocene±Pliocene tectonics South Carpathians foredeep becomes tectonically active only in Late Miocene, further Pliocene defor- 4.2.1. Middle Miocene inversion mations being restricted to small scale thrusts and During the late Burdigalian±Early Badenian, the de- folds (e.g., restoration in Fig. 15). formation changes to a NNE±SSW compressional The westward interpretation of the Pericarpathian stress regime (Mat° enco et al., 1997), contractional de- lineament and prolongation along the Timok fault formation being recognised along the whole studied relies just on one well (structure Ciovarnasani, pro®le area (Fig. 16) (Fig. 17). The large scale structures 2, Fig. 5), where Cretaceous of Carpathian type is relate mainly to ESE±WNW directed thrusts and structurally in a higher position than the Burdigalian folds. Associated small scale piggy-back with ESE± of foredeep type. Our seismic interpretation relates this WNW strike can be observed in the central-eastern structural inversion to the activity of the Late Miocene part of the basin. The thrust osets decrease from 736 T. RabaÆgia, L. Mat° enco / Marine and Petroleum Geology 16 (1999) 719±740

Fig. 16. Synthetic correlation of the recorded base level curves in the Getic Depression. Columns represent the interpreted seismic pro®les. Pro®le 10 has not been plotted, being similar to pro®le 11. Note the superposition of the tectonically active areas with the large local variations of the base level.

NNE to SSW, probably disposed in a foreland-break- mainly by transpressive strike-slip duplexes with NW± ing sequence (Fig. 4). SE strike. Transpressional structures with signi®cant The inversion of the pre-existing transtensional uplift are well marked by the oil structural lineaments basin takes place especially along newly formed thrust de®ned by the petroleum industry, such as Piscu planes, truncating the earlier normal faults (e.g., Fig. Stejarului±T° icleni, Colibasi±Bustuchini (Fig. 4). 12). Locally, such as in the central area (e.g., Fig. 13), One main strike-slip system (Jiu±BaÃlteni±T° icleni± inversion of the NNE dipping normal faults can be Piscu Stejarului, Fig. 4), observed up to 7 s TWT on documented during the Late Burdigalian. In these seismic lines (e.g., Fig. 11) separates areas with dier- areas, the syn-rift deposits are thrust on top of the ent kinematics. While to the west, deformation relates pre-Miocene tilted blocks. The shortening increases mainly to NNW±SSE trending transpressive structures, eastward, as documented by the larger number and in the eastern areas, the NW±SE trending transcurrent oset of the thrust faults and associated folds, organ- motion is coeval with large scale reactivation of the ised in imbricated fans. In this area the larger contrac- WNW±ESE to W±E trending Late Burdigalian tion degree generates regional scale anticlines with thrusts. The Pericarpathian thrust is the main structure Upped Miocene syntectonic sedimentation (e.g., Fig. (re)activated during this timespan and divides the 8). deformed foredeep in the north (the Subcarpathian nappe), from the undeformed part, developed south- 4.2.2. Late Miocene dextral transpression ward. The large scale thrust structures developed in Starting with the Middle Sarmatian times, large this transpressional regime are related to the shape of scale transcurrent motions were recorded in the Getic the downbending Moesian platform, which under- Depression (Fig. 17). Deformation is characterised thrust the South Carpathians nappe pile during this T. RabaÆgia, L. Mat° enco / Marine and Petroleum Geology 16 (1999) 719±740 737

bearing structures, such as Bilteni, Ticleni, Colibasi, Piscu Stejarului (Fig. 4).

4.3. Middle Miocene±Pliocene sedimentological model

Due to the lateral variations of the structural patterns, the Middle Miocene±Pliocene evolution of the Getic Depression can be divided into three dierent sedimentological models, in correspondence with the tectonic areas de®ned in the basin. In the western areas (west of Jiu valley, Figs. 4 and 16), where the deformations are limited, the seismic sequences are controlled by the eustatic/climatic changes. The system tract package has non-typical features in comparison with the Vail et al. (1977) model, due to the pre-existing extensional paleomorphology created by the Early Miocene tectonic episode. Generally, the TST-s are almost lacking, the LSST are well developed and are dominated by the parallel con- ®gurations in relationship to the lateral transport. The HSST do not prograde on top of the LSST, because when a small base level rise occurs, an important lateral migration of the depocenter takes place. This moment appears when the morphological high due to Pre-Miocene tilted block becomes submerged. Horizontal compensation between the HSST-s and LSST-s depocenters takes place at small base level variations. The HSST sediments are not entirely eroded during the LSST periods, because of the parallel-basin morphological breaks, but these sediments are re-deposited in subaerial fans. This type of evolution is attenuated upward, as the extensional structures are covered. The transpressional tectonic control is con- Fig. 17. Sketch of the Tertiary tectonic evolution of the South ®ned to local small-scale prograding bodies, developed Carpathians foredeep. Description in the text. around the NW±SE trending transpressional uplifts. In the central±western area (west of Gilort valley, tectonic event. In fact, the whole Subcarpathians Figs. 4 and 16) the Middle Miocene±Pliocene nappe, as classical de®ned in the geological literature, sequences are genetically connected to NW±SE trend- was emplaced during this transpressional regime, and ing uplifts due to coeval strike-slip structures. These can be recognised with large thrusting characteristics uplifted areas generate local tectonic unconformities, only east of the Olt valley (Fig. 1). well marked by truncations and the symmetrical onlapping on both uplift ¯anks. Such an unconformity represents a marker for the moment when the 4.2.3. Early Pliocene sinistral strike-slip morphological high is large enough to involve a The last deformation episode recorded in the area is change in the geometry of the sedimentary bodies, and related to a NNE±SSW trending sinistral transcurrent does not assume major paleobathymetric variations. deformation during the Early Pliocene (Latest Locally, small prograding bodies could have the Sarmatian±Meotian) (Figs. 4 and 17). Coeval conju- uplifted area as sediment source. As well as in the wes- gate NE±SW trending right-lateral faults are also tern area, the same eustatic unconformities are also observed. An associated small-scale transpressional observed, dierences being recorded in the tectonically character can be de®ned along the strike-slip faults. active areas, and remain the same on southern unde- The oset of the sinistral strike-slip faults is in the formed margin of the basin. Such structures become order of 3±5 km. important hydrocarbon traps, sealing littoral sands in Large scale uplifted areas develop at the intersection distal pelitic deposits. Termination pattern maps show between the Late Miocene dextral faults and the Early their juxtaposition over the major NW±SE/N±S trans- Pliocene sinistral ones, well marked by the largest oil- pressional structures (Fig. 18, comparison with Fig. 4). 738 T. RabaÆgia, L. Mat° enco / Marine and Petroleum Geology 16 (1999) 719±740

Fig. 18. Stratal termination pattern map of the Upper Miocene±Lower Pliocene period. A, Sarmatian level; B, Meotian level

These structures divide small-scale sub-basins, where The hanging-wall of the thrust faults de®ne a ®rst the main sediment transport is probably longitudinal, order active morphological zone and a newly formed towards the major basin located SE-ward. source area, which is parallel with the basin margin. In the central-eastern area (west of Olt valley, Fig. Thus, the thrust fault trace represents a subsidence 16), the main features relate to the development of the hinge line, the basin being divided in dierent sedimen- E±W trending imbricated thrust system, at the same tation areas in respect to this fault. The evolution is time as the activation of the NW±SE trending trans- furthermore complicated by the second order uplifted pressional uplifts. The lowermost Sarmatian seismic areas induced by the transpressional faults, oriented sequences are divided into a large number of ``tec- transverse to the basin margins. These areas allow tonic'' system tracts, with apparent eustatic control. sediments transfer across the previously mentioned T. RabaÆgia, L. Mat° enco / Marine and Petroleum Geology 16 (1999) 719±740 739

®rst order uplifted areas (Fig. 18). In contrast, sedi- In the active tectonic areas, due to the Middle mentation records eustatic variations in places where Miocene±Pliocene deformations, many local seismic no signi®cant tectonic uplift occurs. sequences appear, which can be still considered to be depositional sequences. The limited lateral extent, controlled by the active morphological areas, reveal that 5. Discussions and conclusions these depositional sequences do not record eustatic variations, but show mainly a tectonic control of local We have demonstrated in the previous sections that base level changes. The tectonic uplift values are high the Tertiary evolution of the South Carpathians fore- enough to mask the eustatic control, for instance the deep is mainly characterised by large scale Early Sarmatian uplift reached 1 m/1000 years (RaÆ baÆ gia & Miocene (Early Burdigalian) extension/transtension, FuÈ lop, 1994). The unconformities which divide the tec- Middle Miocene (Late Burdigalian±Badenian) contrac- tonic sequences can be de®ned as tectonic sequence tion and Late Miocene±Early Pliocene (Sarmatian± boundaries (TSB), being characterised by low lateral Early Meotian) transpression. correlation, low paleobathymetrical variations and Accepted plate tectonic models for the Carpathians± time/space evolution linked to the basin structural pat- Pannonian system (e.g., Csontos, 1995; Ratschbacher terns. et al., 1993; SaÆ ndulescu, 1984) generally assume that This ®nding supports the conclusion of the domi- the Carpathians orogen formed as a consequence of N nant tectonic control of the sedimentary sequences in and E-ward translation of one or more continental the foreland basins. The eustatic control may be as- blocks (Dacidic and other) and subsequent collision sociated, but has a clear subordinated character. with the Moesian platform in the south and the East European platform in the east and north. During the Early Miocene (Early Burdigalian), the Acknowledgements large scale clockwise rotation of the Rhodopian fragment (Csontos, 1995), associated with its NE-ward This paper is the result of a common cooperation movement (Mat° enco, 1997), induced the transtensional work between the Prospect° iuni S.A., Hydrocarbon opening of the Getic basin along a roughly E±W Division, Bucharest and Faculty of Geology and oriented shear corridor, de®ning a regional dextral Geophysics, University of Bucharest. Special thanks pull-apart basin (Fig. 17). Clockwise rotation of the are addressed to A. M. FuÈ lop for the creative support South Carpathians created major dextral transten- in understating the eastern Getic Depression, to O. sional deformations at the contact with the Moesian Dicea and C. Dinu for useful ideas, helpful comments Platform and dierent normal fault patterns within the and continuing support. M. TaÆ raÆ poancaÆ is thanked for Getic basin, their strike changing from NE±SW in the understanding the kinematics of the Intramoesian west to WNW±ESE in the east (Fig. 17). Further east- fault. ern deformation is taken up by the Intramoesian fault, with NW±SE trending dextral character. The Paleogene NE±SW to E±W opening of the Petros° ani References basin (Ratschbacher et al., 1993) and the large scale E±W orogen parallel extension observed at the contact Berza, T., & DraÆ gaÆ nescu, A. (1988). The Cerna-Jiu fault system between the Getic/Danubian nappes (Schmid, Berza, (South Carpathians, Romania), a major Tertiary transcurrent Diaconescu, Froitzheim & Fuegenschuh, 1998) in the lineament. D.S. Inst. Geol. Geo®z., 72(73), 43±57. South Carpathians nappe pile would suggest the mi- Bojar, A. V., Neubauer, F., & Fritz, H. (1998). Jurassic to Cenozoic gration in time of the transtensional/extensional defor- thermal evolution of the southwestern South Carpathians: evi- dence from ®ssion-track thermochronology. Tectonophysics, mation towards the foreland. 297(14), 229±249. The Miocene±Pliocene sedimentological evolution of Burch®el, B. C. (1976). Geology of Romania. Spec. Paper. 158, the Getic basin is mostly resumed in base level vari- Geological Society of America, 82 pp. ation curves (Fig. 16). The tectonic control is well Codarcea, A. (1940). Vues nouvelles sur la tectonique du Banat et marked on these curves, both on the syn-rift sediments du Plateau du Mehedint° i. An. Inst. Geol. Rom., XX, 1±74. (Early Miocene) and on the syn-compressional/trans- Crumeyrolle, P., Rubino, J., & Clauzon, G. (1991). Miocene depositional sequences within a controlled transgressive-regressive cycle, pressional sediments (Middle/Late Miocene±Earliest Sedimentation, tectonics and eustasy, International Association of Pliocene). The eustatic sequence boundaries change Sedimentologists, Special Publication, 12, 374±390. their character in the active morphological areas, but Csontos, L. (1995). Tertiary tectonic evolution of the Intra- still remain unconformities. The parts of a eustatic Carpathian area: a review. Acta Vulcanologica, 7, 1±13. Dicea, O. (1995). The structure and hydrocarbon geology of the sequence boundary (ESB) which develop both under Romanian East Carpathians border from seismic data. Petroleum tectonic and eustatic control could be considered as a Geoscience, 1, 135±143. mixed sequence boundary (MSB). Dicea, O. (1996). Tectonic setting and hydrocarbon habitat of the 740 T. RabaÆgia, L. Mat° enco / Marine and Petroleum Geology 16 (1999) 719±740

Romanian external Carpathians. In P. A. Ziegler, & F. Horvath, Royden, L. H., & BaÂ ldi, T. (1988). Early Cenozoic tectonics and Peri-Tethys Memoir 2: Structure and prospects of Alpine basins paleogeography of the Pannonian and surrounding regions. In L. and forelands (pp. 403±425). In MeÂmoires du Museum national H. Royden, & F. Horvath, The Pannonian Basin, a study in basin d'Histoire naturelle, 170. evolution (pp. 1±16). In AAPG Memoir, 45. Jipa, D. (1980). Sedimentological features of the basal paleogene in Robertson, A. H. F., Eaton, S., Follows, E. J., & McCallum, J. the VaÃ lsan valley, in cretaceous and tertiary molasses. In The (1991). The role of local tectonics versus global sea-level change, Eastern Carpathains and Getic Depression. Guidebook ®eldworks the Neogene evolution of the Cyprus active margin, group 3.3. Bucharest: Inst. Geol. s° i Geo®z. Sedimentation, tectonics and eustasy, International Association of Jipa, D. (1982). Explanatory notes to the lithotectonic pro®le of the Sedimentologists, Special Publication, 12, 331±369. Getic Paleogene deposits (Southern Carpathians, Romania) RoÈ gl, F. (1996). Stratigraphic correlation of Paratethys Oligocene (Sedimentological Comment to Annex 13). Vero. Zentralinst. and Miocene. Mitt. Ges. Geol. Bergbaustud. OÈsterr., 41, 65±73. Phys. Erde AdW DDR, 66, 137±146. Sanders, C. A. E. (1998). Tectonics and erosion. Competitive forces Jipa, D. (1984). Large scale progradation structures in the Romanian in a compressive orogen. A ®ssion track study of the Romanian Carpathians: Facts and hypothesis. An. Inst. Geol. Geo®z., LXIV, Carpathians. PhD thesis, Vrije Universiteit, Amsterdam, 204 pp. 455±463. Leckie, D.A., Smith, D.G. (1992). Regional setting, evolution and SaÆ ndulescu, M. (1984). Geotectonica RomaÃniei (in Romanian), Ed. depositional cycles of the Western Canada foreland basin. Tehnica, Bucharest, 450 pp. Foreland basins and fold belts, Macqueen, R.W., & Leckie, D.A., SaÆ ndulescu, M. (1988). Cenozoic tectonic history of the Carpathians. (Eds.) AAPG Memoir, pp. 9±46. In L. H. Royden, & F. Horvath, The Pannonian Basin, a study in Mat° enco, L. (1997). Tectonic evolution of the Romanian Outer basin evolution (pp. 17±25). In AAPG Memoir, 45. Carpathians: Constraints from kinematic analysis and ¯exural Schmid, S. M., Berza, T., Diaconescu, V., Froitzheim, N., & modeling. PhD thesis, Vrije Universiteit, Amsterdam, 160 pp. Fuegenschuh, B. (1998). Orogen-parallel extension in the South Mat° enco, L., Bertotti, G., Dinu, C., & Cloetingh, S. (1997). Tertiary Carpathians during the Paleogene. Tectonophysics, 297, 209±228. tectonic evolution of the external South Carpathians and the Steckler, M. S., & Watts, A. B. (1978). Subsidence of the Atlantic- adjacent Moesian platform (Romania). Tectonics, 16, 896±911. type continental margin o New York. Ear. Pl. Sci. Lett., 41,1± Mat° enco, L., & Schmid, S. (1999). Exhumation of the Danubian 13. nappes system (South Carpathians) during the Early Tertiary: Stefanescu, M., & working-group (1988). Geological cross sections at inferences from kinematic and paleostress analysis at the Getic/ scale 1:200.000, no. B1-B6. Inst. Geol. Geo®z., Bucharest. Danubian nappes contact. Tectonophysics (in press). Sza®an, P. (1999). Gravity and tectonics: A study case in the Motas° , C. (1983). Nouvelles donneÂ s sur les rapports structuraux Pannonian basin and the surrounding mountain belt. PhD Thesis, entre les Carpathes MeÂ ridionales et la deÂ pression geÂ tique. Lucr. Vrije Universiteit, Amsterdam, 154 pp. Congr. XXI Assoc. Carp-Balc. An. Ist. Geol. Geo®z., 60, 141±146. Szasz, L. (1975). Biostratigra®a s° i paleontologia Cretacicului superior Murgoci, G. M. (1905). Contributions aÁ la tectonique des Karpathes din bazinul Brezoi. DaÆri de seamaÆ ale s° edintelor, LXII, 189±220. MeÂ ridionales. C. R. Acad. Paris, 23, 23±47. Tari, G., HorvaÂ th, F., & Rumpler, J. (1992). Styles of extension in Paraschiv, V. (1975). Geologia zacamintelor de hidrocarburi din the Pannonian basin. Tectonophysics, 208, 203±219. Romania. Ed. Tehnica, Bucures° ti, 350 pp. Vail, P. R., Mitchum, R. M., Todd, R., Widmier, J., Thompson, S., Prosser, S. (1993). Rift related linked depositional system and their Sangree, J., Bubb, J., & Hatlelid, W. (1977) Seismic stratigraphy seismic expression, Tectonics and Seismic Sequence Stratigraphy, and global changes of sea level: Application of seismic re¯ector Geological Society Special Publication, 71, 35±66. Ratschbacher, L., Linzer, H. G., Moser, F., Strusievicz, R. O., con®guration to stratigraphic interpretations, Seismic stratigra- Bedelean, H., Har, N., & Mogos, P. A. (1993). Cretaceous to phy-application to hydrocarbon exploration, AAPG Memoir, 36, Miocene thrusting and wrenching along the central South 129±144. Carpathians due to a corner eect during collision and orocline Watts, A. B., Karner, G. D., & Steckler, M. S. (1982). Lithosphere formation. Tectonics, 12, 855±873. ¯exure and the evolution of sedimentary basins. Philosophical RaÆ baÆ gia, T., & FuÈ lop, A. (1994). Syntectonic sedimentation history Transactions of the Royal Society of London, 305, 249±281. in the Southern Carpathians foredeep, Berza, T., ALCAPA II: Woodward, N. B., Boyer, S. E., & Suppe, J. (1989). Balanced geo- Geological Evolution of the Alps±Carpathian±Pannonian System, logical cross sections: An essential technique in geological Abstracts volume, Romanian Journal of Tectonics and Regional research and exploration. Short course in geology, 6. AGU, 132 Geology, 75, 48. pp.