Abstract Turkey is sited at the collisional boundary between Gondwana in the south and Laurasia in the north and its geological history records the suturing of a succession of continental fragments. The Tethyan ocean, which existed between Laurasia and Gondwana, was not a single continuous oceanic plate, but rather comprised variable-sized continental fragments throughout its history (Fig. 1). These rifted from the Gondwana margin and, as the rifts widened, created oceans (mainly described as Prototethys, Palaeotethys and Neotethys in the literature), then subsequently collided with Laurasia so that these oceans sequentially closed. The present tectonic regime follows closure of the Neotethyan ocean. Although Prototethys has traditionally been regarded as a Late Proterozoic and/or Early Palaeozoic ocean, Palaeotethys as a Palaeozoic ocean and Neotethys as a Mesozoic-Early Tertiary ocean, the views expressed in this volume show that there is no common agreement. Many alternative models have been proposed for their evolution and they may, indeed, have overlapped in time. The models proposed below differ in subduction polarity, timing of ocean basin opening and closure, and in the location of suture zones. Figure 1 is a simplified tectonic map showing the location of the main Tethyan sutures and neighbouring major continental blocks in Turkey and its surrounding area.

Abstract Diachronous subsidence patterns of Tethyan margins since the Early Palaeozoic provide constraints for paleocontinental reconstructions and the opening of disappeared oceans. Palaeotethys opening can be placed from Ordovician to Silurian times and corresponds to the detachment of a ribbon-like Hun Superterrane along the Gondwanan margin. Neotethys opening took place from Late Carboniferous to late Early Permian from Australia to the eastern Mediterranean area. This opening corresponds to the drifting of the Cimmerian superterrane and the final closing of Palaeotethys in Middle Triassic times. Northward subduction of Palaeotethys triggered the opening of back-arc oceans along the Eurasian margin from Austria to the Pamirs. The fate of these Permo-Triassic marginal basins is quite different from areas to area. Some closed during the Eocimmerian collisional event (Karakaya, Agh-Darband), others (Meliata) stayed open and their delayed subduction induced the opening of younger back-arc oceans (Vardar, Black Sea). The subduction of the Neotethys mid-ocean ridge was certainly responsible for a major change in the Jurassic plate tectonics. The Central Atlantic ocean opened in Early Jurassic time and extended eastwards into the Alpine Tethys in an attempt to link up with the Eurasian back-arc oceans. When these marginal basins started to close the Atlantic system had to find another way, and started to open southwards and northwards, slowly replacing the Tethyan ocean by mountain belts.

Abstract A belt of Late Triassic deformation and metamorphism (Cimmeride Orogeny) extends east-west for 1100 km in northern Turkey. It is proposed that this was caused by the collision and partial accretion of an Early-Middle Triassic oceanic plateau with the southern continental margin of Laurasia. The upper part of this oceanic plateau is recognized as a thick Lower-Middle Triassic metabasite-marble-phyllite complex, named the Nilüfer Unit, which covers an area of 120 000 km 2 with an estimated volume of mafic rocks of 2 × 10 5 km 3 . The mafic sequence, which has thin stratigraphic intercalations of hemipelagic limestone and shale, shows consistent within-plate geochemical signatures. The Nilüfer Unit has undergone a high-pressure greenschist facies metamorphism, but also includes tectonic slices of eclogite and blueschist with latest Triassic isotopic ages, produced during the attempted subduction of the plateau. The short period for the orogeny (< 15 Ma; Norian-Hettangian) is further evidence for the oceanic plateau origin of the Cimmeride Orogeny. The accretion of the Nilüfer Plateau produced strong uplift and compressional deformation in the hanging wall. A large and thick clastic wedge, fed from the granitic basement of the Laurasia, represented by a thick Upper Triassic arkosic sandstone sequence in northwest Turkey, engulfed the subduction zone and the Nilüfer Plateau.

Abstract Similar Palaeozoic-Lower Tertiary units in the northern Karaburun Peninsula (western Turkey) and the adjacent island of Chios (Greece) provide insights into the tectonic evolution of the Tethyan Ocean near the junction between the Taurides/Anatolides and Hellenides. The northwest Karaburun Peninsula is dominated by a highly sheared mélange ( c. τ 2 km thick) with Silurian-Carboniferous blocks (up to hundreds of metres in size) of neritic and pelagic limestone, black ribbon chert, shale, extrusives and volcanogenic sediments. The blocks are set in a matrix of siliciclastic turbidites, pelagic carbonates and channelized conglomerates. Northern Chios is similarly composed of mélange ( c. 3–4 km thick) with limestone blocks dated as Silurian-Carboniferous, black ribbon chert, shale and volcanics within predominantly siliciclastic sediments, including local conglomerates. Both mélanges are unconformably overlain by Lower Triassic basinal successions (with sheared basal contacts), including terrigenous clastics, pelagic carbonate, radiolarite, lava and volcanogenic sediments, interpreted as rift successions. In both areas, successions shallow upwards into extensive Mesozoic carbonate platform facies, similar to those widely developed in the Taurides and Hellenides. On the Karaburun Peninsula, deposition was punctuated by emergence and localized deltaic siliciclastic deposition in latest Triassic-earliest Jurassic time. The Karaburun carbonate platform later emerged, eroded, then subsided in Campanian-Maastrichtian time; it then collapsed in the Maastrichtian-earliest Tertiary and was overlain by another mélange (Bornova Mélange), with blocks of both local platform-derived and accreted Mesozoic oceanic lithologies, and was finally thrust imbricated during continental collision. On Chios, a Lower Jurassic carbonate platform succession is overthrust by an exotic Carboniferous-Lower Jurassic mixed shallow-water carbonate and siliciclastic unit. Most tectonic hypotheses for the mélange are problematic. They include formation as Palaeozoic basinal ‘olistostromes’, as an ideal Late Palaeozoic subduction-accretion complex basin, as an Early Triassic rift, or as entirely tectonic mélange. The mélange are seen here as the end-product of a combination of Late Palaeozoic southward(?) subduction-accretion (culminating in trench-microcontinent collision?), Early Triassic rifting and latest Cretaceous-Early Tertiary subduction/collision. Regional comparisons suggest that initial mélange formation took place in Late Carboniferous-Early Permian time. Subsequent Early Triassic rifting was associated with siliciclastic, calcareous and radiolarian deposition, and andesitic volcanism. The Triassic rift was overlain by a subsiding passive margin adjacent to a northerly Neotethyan oceanic basin from Middle Triassic-Late Cretaceous. This ocean closed in the Late Cretaceous-Early Tertiary, resulting in collapse of the passive margin, subduction-accretion and further mélange formation in a foredeep. Continental collision resulted in further deformation of the Palaeozoic mélange, thrust imbrication of the Mesozoic platform and shearing at its base.

Abstract Upper Permian marine carbonates are distinguished in two contrasting biofacies belts in Turkey. The Southern Biofacies Belt, represented by low-energy inner platform deposits of the Tauride Belt and the Arabian Platform, is rich in algae and smaller foraminifera but poor in fusulines. The Kubergandian and Murgabian stages are missing, although the rest of the Upper Permian consists of monotonous, shallow-marine carbonate deposits. The extremely tectonised and fragmented Northern Biofacies Belt includes the Upper Permian of the Karakaya Orogen and outer platform or platform margin deposits of the Tauride Belt. These deposits are rich in parachomata-bearing fusulines comprising Cancellina, Verbeekina, Afghanella, Sumatrina, Neoschwagerina and Yabeina . The reconstructed biostratigraphic scheme indicates that all Upper Permian stages (Kubergandian-Dorashamian) are present. The lateral continuity of the two biofacies belts is detected by the presence of tongues of he Northern Biofacies Belt pinching out in the Southern Biofacies Belt. Upper Permian blocks in the Karakaya Orogen display similar palaeontologic and biofacies characteristics, with the outer platform or platform margin deposits of the Taurides constituting the northernmost extension of the carbonate platform. This platform was probably facing a basin or a trough to the north. The lack of any transgressive Upper Permian deposits resting unconformably on the pre-Permian basement of the Sakarya Continent strongly suggests that such a basin was located between the Late Permian carbonate platform in the south and the basement rocks of the future Sakarya Continent in the north.

Abstract This paper focuses on the Mesozoic-Tertiary tectonic evolution of southern Turkey and offshore areas of the easternmost Mediterranean. The area is discussed and interpreted utilizing three segments from west to east. In the far west, the Lycian Nappes represent emplaced remnants of mainly Mesozoic rift, passive margin and oceanic units that formed within a northerly strand of the Mesozoic (i.e. Neotethyan) ocean. Further east, the Hoyran-Beyşehir-Hadim Nappes, likewise encompass sedimentary and igneous units that formed within a northerly Neotethyan oceanic basin, although lithologies, structure and timing of emplacement differ from the Lycian Nappes. Further east (Adana region), ophiolites and ophiolitic mélange also formed in a northerly oceanic basin and were thrust southwards over the regionally extensive Tauride carbonate platform initially in latest Cretaceous time (e.g. Pozanti-Karsanti Ophiolite). By contrast, further south the regionally important Antalya Complex records northerly areas of a separate, contrasting southerly Neotethyan oceanic basin. This comprised a mosaic of carbonate platforms and interconnecting seaways, similar to the Caribbean region today. In particular, an ocean strand separated Tauride carbonate platforms to the west (Bey Dağlari) and east (e.g. Akseki Platform) within the Isparta Angle area. In the centre of southern coastal Turkey, the metamorphic Alanya Massif is interpreted as a Triassic rift basin bordered by two small platform units that was located along the northern margin of the southerly Neotethys which collapsed in latest Cretaceous and was finally emplaced in Early Tertiary time. Remnants of the southerly Neotethyan oceanic basin remain today in the non-emplaced continental margin of the Levant and North Africa, and neighbouring seafloor areas (e.g. Levant and Herodotus Basins). In southern Turkey, emplaced Neotethyan units are unconformably overlain by a complex of mainly Miocene basins. These largely reflect the effects of southward directed crustal loading as convergence of Africa and Eurasia continued, although the basins were also influenced by an inferred more southerly subduction zone (near Cyprus). Further east, in southeastern Turkey, ophiolites, ophiolitic mélange and continental margin units were emplaced southwards onto the Arabian Margin, a promontory of North Africa in latest Cretaceous time. The south Neotethyan basin’s north margin experienced northward subduction, accretion, arc volcanism and ophiolite emplacement in Late Cretaceous time. The intervening southerly Neotethyan oceanic basin remained partly open in the Early Tertiary, finally closing by diachronous collision in Eocene-Oligocene time, followed by further convergence and overthrusting in the Miocene. The Eocene later stages of convergence were marked by renewed arc volcanism and extensive subduction accretion (e.g. Maden Complex). In the west, subduction remained active in Late Oligocene-Early Miocene time giving rise to sedimentary mélanges (olistostromes) of the Misis-Andirin Mountains (Adana region) as an accretionary wedge. By the Miocene the subduction zone accommodating Africa-Eurasia convergence had been relocated to its present position south of Cyprus. Areas behind this subduction experienced crustal extension (e.g. Antalya and Adana-Cilicia Basins) from the Late Miocene onwards. After onset of westward ‘tectonic escape’ of the Turkish Plate in the Early Pliocene, southeastern Turkey was transected by the South Anatolian Transform Fault. Strike-slip was dissipated though the Kyrenia-Misis Lineament into Cyprus. Today, southeastern Turkey records a post-collisional setting, whereas areas to the west experience incipient collision of the African and Turkish Plates.

Abstract In the Central Sakarya area of Turkey there are two main Alpine continental units, separated by a south verging ophiolitic complex which represents the root zone of the İzmir-Ankara Suture Belt. The Central Sakarya Terrane in the north includes two ‘Variscan’ tectonic units in its basement. The Söğüt Metamorphic rocks represent a Variscan ensimatic arc complex and the Tepeköy Metamorphic rocks are characteristically a forearc-trench complex. The unconformably overlying Triassic Soğukkuyu Metamorphic rocks correspond to a part of the Karakaya Formation and are interpreted as a Triassic rift basin assemblage. These units are unconformably overlain by a transgressive sequence of Liassic-Late Cretaceous age that represents the northeastward deepening carbonate platform of the Sakarya Composite Terrane. The middle tectonic unit (the Central Sakarya Ophiolitic Complex) comprises blocks and slices of dismembered ophiolites, blueschists and basic volcanic rocks with uppermost Jurassic-Lower Cretaceous radiolarite-limestone interlayers. Geochemical data from basalt blocks suggest mid-ocean ridge basalt (MORB)- and suprasubduction-type tectonic settings within the Neotethyan İzmir-Ankara Ocean. The southern tectonic unit includes basal polyphase metamorphosed clastic rocks (Sömdiken Metamorphics), intruded by felsic and basic dykes and overlain by thick-bedded marbles. This assemblage is unconformably overlain by continental clastic rocks gradually giving way to thick-bedded recrystallized limestones, cherty limestones and pelagic limestones intercalated with radiolarites, and finally by a thick high pressure-low temperature (HP-LT) metamorphic synorogenic flysch sequence. This succession is identical to the passive continental margin sequences of the Tauride Platform. It is suggested that this passive margin was subducted during the Late Cretaceous in an intraoceanic subduction zone and affected by HP-LT metamorphism. The emplacement of the allochthonous oceanic assemblages and the collision with the Central Sakarya Terrane was complete by the end of the Cretaceous.

Abstract The Barla Dağ area of southwestern Turkey and its surroundings represent one of the most characteristic Tethyan regions in which the unique characteristics of the Jurassic radiolarite deposits permit detailed study of this enigmatic facies. Hitherto, radiolarites of Western Tethys have not been studied in sufficient detail to yield the information required for unequivocal interpretation of this siliceous sedimentary event. Moreover, few of the occurrences of Tethyan radiolarites during the Jurassic have been adequately explained by palaeoenvironmental causes deduced from facies analysis. In the Barla Dağ area, the main radiolarite episode began after the ‘main gap’ or mid-Late Jurassic discontinuity, a 25 Ma hiatus extending from the Early Bajocian to the Kimmeridgian. These radiolarites are interbedded with biocalcarenites characterized by shallow-water shells. They formed in a ramp environment subject to strong storm oscillatory movements and were deposited within, or just below, wave base. Pre-existing platforms were converted into ramp settings by a widespread drowning episode, mainly following postulated regional warping that led to creation of the ‘main gap’. Coincident with this event, the differentiation of rimmed platform lagoonal organisms and typical ramp inhabitants, such as Tubiphytes , took place. Furthermore, nearby platforms, unaffected by the extensional faulting (e.g. the Davras Dağ), were sites of carbonate accumulation receiving only a few radiolarians. On the other hand, displaced shallow-water organisms of the same age (typical of the restricted lagoons flanking the rimmed platforms such as pfenderinas, kurnubias and Clypeina jurassica ) are absent from the sequences of calcarenites interbedded with radiolarian cherts. Replacement of deep basins by ramps is indicated by the changing depositional bathymetry of some radiolarites. It is tentatively attributed to the extension of shallow seas and narrowing of the oceanic realm between Eurasian and African Plates in Western Tethys.

Abstract The eastern Pontides (northeastern Turkey) and Transcaucasus (Georgia) belong to the same geological belt representing an active margin of the Eurasian continent. According to palaeotectonic–palaeogeographic reconstructions, based on regional geological, palaeomagnetic, palaeobiogeographical and petrological data, the eastern Pontides and the major part of the Transcaucasus, situated to the north of the North Anatolian–Lesser Caucasian ophiolitic suture, comprise island arc, forearc, back and interarc basins. The eastern Pontide segment of the belt consists of three structural units which, from north to south, are the northern, central and southern units. The northern unit, the southeastern Black Sea coast–Adjara–Trialeti Unit, represents a juvenile back arc basin formed during the Late Cretaceous (pre-Maastrichtian). This unit separates the southern and northern Transcaucasus zones. The central Artvin–Bolnisi Unit is also known as the northern part of the southern Transcaucasus and is characterized by Hercynian basement, unconformably overlying the Upper Carboniferous–Lower Permian molasse and Upper Jurassic–Cretaceous arc association. The southern unit is the imbricated Bayburt–Karabakh Unit and is known as the southern part of the southern Transcaucasus. This unit has a similar basement to the Artvin–Bolnisi Unit and also includes a chaotic assemblage; it unconformably overlies the Upper Jurassic–Cretaceous forearc association. The eastern Pontide system is interpreted as the product of interference between a spreading ridge and subduction zone during Late Jurassic–Cretaceous times. The North Anatolian–Lesser Caucasus Suture, comprising ophiolites, mélanges and an ensimatic arc association, separates the overlying system from the Anatolian–Iranian Platform in the south. Maastrichtian–Lower Eocene cover rocks in the region unconformably overlie all the other units. Middle Eocene rifting resulted in the formation of new basins, some of which closed during an Oligocene–Early Miocene regression. Others, such as the Black Sea and Caspian Basins, have survived to the present day as relict basins.

Abstract The Central Anatolian Crystalline Complex (CACC) or Kırşehir Block is part of the metamorphosed leading edge of the Tauride–Anatolide Carbonate Platform. It contains oceanic remnants derived from the Neotethys Ocean (İzmir–Ankara–Erzincan branch) which separate it from the Sakarya microcontinent. Two tectonic units are distinguished: an amphibolite facies Mesozoic ‘basement’, dominated by platform marbles, over which is thrust a younger fragmented Upper Cretaceous ophiolite sequence. Three metabasite horizons were sampled to reconstruct the development of the oceanic components: (1) fragmented Upper Cretaceous (90–85 Ma) stratiform ophiolitic members comprising gabbros, sheeted dykes, basalt lavas and pelagic sediments thrust over all other units; (2) a tectonised admixture of basite, ultramafic and felsic blocks in an ophiolitic mélange (Upper Cretaceous matrix) thrust over the basement metamorphic rocks; and (3) amphibolites concordant with ‘basement’ marbles and minor pelagics of the largely (?)Triassic Kaleboynu Formation in the lower part of the carbonate platform. Metabasalts and metagabbros from isolated fragments of the stratiform ophiolites form geochemically coherent groups and indicate the influence of a subduction component during their development. It is considered that the suprasubduction zone ophiolites record the association of a tholeiitic arc and an adjacent back-arc basin with more mid-ocean ridge basalt (MORB)-like compositions. Metabasite blocks within the tectonised ophiolitic mélange slice are MORB like, together with minor ocean island basalt (OIB) and island arc basalts, and may be tectonically related to ophiolitic units within the accretionary wedge of the Ankara Mélange. Concordant amphibolites of the Kaleboynu Formation are largely OIB types and reflect an early ensialic rifting stage of the Tauride–Anatolide Carbonate Platform. Small ocean basins also developed at this time, as recorded by the presence of MORB and associated pelagics. The CACC block, together with parts of the Ankara Mélange, are considered to represent oceanic lithosphere (comprising both early spreading centre and latter subduction-influenced crust) and continental carbonate platform that were subsequently ejected from an accretionary–subduction complex on collision with the Sakarya microcontinent.

Abstract The Central Anatolian Ophiolites (CAO) comprise a number of little studied Upper Cretaceous ophiolitic bodies that originally represented part of the northern branch of the Neotethyan ocean. The Çiçekdağ Ophiolite (CO) is an dismembered example of this ophiolite group that still retains a partially preserved magmatic pseudostratigraphy. The following units (bottom to top) can be recognized: (1) layered gabbro; (2) isotropic gabbro: (3) plagiogranite; (4) dolerite dyke complex; (5) basaltic volcanic sequence; and (6) a Turonian-Santonian epi-ophiolitic sedimentary cover. The magmatic rock units (gabbro, dolerite and basalt) form part of a dominant comagmatic series of differentiated tholeiites, together with a minor group of primitive unfractionated basalts. The basaltic volcanics mainly consist of pillow lavas with a subordinate amount of massive lavas and rare basaltic breccias. Petrographic data from the least altered pillow lavas indicate that they were originally olivine-poor, plagioclase-clinopyroxene phyric tholeiites. Immobile trace element data from the basalt lavas and dolerite dykes show a strong subduction-related chemical signature. Relative to N-mid-ocean ridge basalt the Çiçekdağ basaltic rocks (allowing for the effects of alteration) have typical suprasubduction zone features with similarities to the Izu-Bonin Arc, i.e. enriched in most large-ion lithophile elements, depleted in high field strength elements and exhibiting depleted light rare earth element patterns. The geochemical characteristics are similar to other eastern Mediterranean Neotethyan SSZ-type ophiolites and suggest that the CO oceanic crust was generated by partial melting of already depleted oceanic lithosphere within the northern branch of the Neotethyan ocean. The Çiçekdağ body, along with the other fragmented CAO, is thus representative of the Late Cretaceous development of new oceanic lithosphere within an older oceanic realm.

Abstract The Pozanti-Karsanti Ophiolite Complex is situated in the eastern Tauride Belt and represents a remnant of the Mesozoic Neotethyan Ocean. It consists of three distinct nappes: (1) an ophiolitic mélange; (2) a metamorphic sole; and (3) ophiolitic rocks. The oceanic lithosphere section of the Pozanti-Karsanti Ophiolite comprises mantle tectonites, ultramafic-mafic cumulates, isotropic gabbros, sheeted dykes and basaltic volcanic rocks. These units are cut by isolated microgabbro-diabase dykes at all structural levels. New results are presented on the whole-rock and mineral chemistry of the gabbroic cumulates. Well-layered, low-Ti gabbroic cumulates, showing adcumulate to mesocumulate textures, are represented exclusively by gabbronorites. The mineral chemistry of gabbronorites from the Pozanti-Karsanti Ophiolite indicates that these cumulate rocks have been produced by the low-pressure crystal fractionation of basaltic liquid. Magnesium numbers (Mg-numbers) of clinopyroxene, orthopyroxene and amphibole range from 89 to 73, 80–66 and 80–72, respectively. Plagioclase compositions range from An 94 to An 84 . The coexistence of calcic plagioclase, magnesian clinopyroxene and orthopyroxene indicates that the cumulate gabbronorites from the Pozanti-Karsanti Ophiolite were formed in an arc environment. The covariation of Al 2 O 3 and Mg-numbers of both clinopyroxene and orthopyroxene show features typical of low-pressure igneous intrusions such as the Skaergaard and Tonsina Complexes, but differ from the high-pressure ultramafic cumulates found in the same arc. The cumulate gabbronorites probably represent shallower levels in the arc which were subsequently juxtaposed against deeper level ultramafic cumulates either during accretion or later faulting.

Abstract Comparison of two sets of structural and thickness maps of the Black Sea Basin produced by Russian and Italian workers revealed important differences in the interpretation of thickness and structure of the lower sedimentary unit, referred to in both works as ‘Palaeocene-Eocene’. The map based on the Italian data shows two depocentres with τ 5 km of sediment in the westernmost part of the Western Black Sea Basin (WBSB), while in the rest of the WBSB and in the Eastern Black Sea Basin (EBSB) the thickness is 2–3 km. Analysis of the land and submarine geology suggests that depocentres correspond to two segments of this system is represented by the Karkinit Graben on the northern shelf of the Black Sea. Submarine studies reveal that the graben originated behind and Early Cretaceous volcanic arc situated on the present day continental slope and rise. Most of the WBSB and the EBSB opened in the Eocene. For the EBSB this age is supported by data on its landward extension — the Adjaro—Trialet Basin. The EBSB could not open due to anticlockwise rotation of the Shatsky Rise because there was no corresponding subduction or shortening in the Greater Caucasus Basin. An alternative hypothesis is that of simultaneous opening of the EBSB and the WBSB as a result of southward drift of the Pontides and clockwise rotation of the Andrusov Rise.

Abstract The Neogene marginal succession of the Eastern Paratethys (EP) crops out along the southern Black Sea coast and in the Marmara region of Turkey, and provides important clues to the tectono-sedimentary and palaeoceanographic conditions. In the Tarkhanian stage, the southern margin of the EP basin was largely a carbonate platform covered by warm, marine waters. From the end of the Tarkhanian to the Early Chokrakian there was an overall emergence throughout the basin, which is indicated by an influx of siliciclastic sediments. The fossil assemblage indicates that normal marine conditions persisted during most of this period, except for a salinity reduction towards the end due to an eustatic isolation of the basin, which in turn led to anoxic bottom water conditions. The Late Chokrakian isolation became even more severe during the Karaganian as indicated by the endemic fossil assemblage indicating brackish-marine conditions. Carbonate platform conditions prevailed in the northern Pontides during this time. In the Early Konkian, the basin was reconnected briefly with the world ocean by a transgression from the Indo-Pacific Ocean. In the Late Konkian there was a return to brackish-marine conditions. Lower Sarmatian sediments are absent in the southern margin of the EP, but elsewhere in the basin this stage is characterized by a widespread marine transgression. In the Middle-Late Sarmatian, the EP basin was partially isolated with freshening and anoxic bottom-water conditions. During this time there was a brief marine transgression from the Mediterranean into the Marmara region, but it did not reach the Paratethyan basin. The Pontian is characterized by an extensive transgression from the EP that inundated the Marmara and northeastern Aegean regions. The connection with the Marmara Basin was cut off during the Kimmerian and re-established during the Late Akchagylian, when the EP basin was inundated by the Mediterranean waters via the Sea of Marmara as a result of increased North Anatolian Fault activity and a short-term global sea level rise.

Abstract The Manavgat Basin is a northwest-southeast oriented basin that developed on the eastern side of the Isparta Angle, south of the Late Eocene thrust belt of the western Taurides. The Miocene fill of the basin lies unconformably on an imbricated basement, comprising a Mesozoic para-authocthonous carbonate platform overthrust by the Antalya Nappes and Alanya Massif metamorphics. The sedimentary fill is represented by clasticdominated deposits consisting of, in ascending order, a conglomeratic wedge, reefal shelf carbonates, limy mudstones, and calciturbidites with subordinate breccias and conglomerates. Process-oriented facies analysis of the basin fill indicates a variety of depositional environments ranging from fluvial/alluvial fan and fan-delta complexes through reefal carbonate shelf and forereef slope to slope fan and basin floor. Fluvial/alluvial fan and fan-delta deposits are Burdigalian-Early Langhian in age and represent the initial conglomeratic valley-fill sedimentation during a relative sea-level rise balanced by important sediment supply from relief in the north-northeast hinterland. The continuous relative sea-level rise and a decreasing rate of sediment supply allowed the deposition of transgressive reefal shelf carbonates of Langhian age. Tectonic activity demonstrated by synsedimentary faults resulted in block faulting of the narrow carbonate shelf and foundering of the basin. The rest of the sedimentation consists of the fill of newly created accommodation space. The overall coarsening-upward succession consists of Upper Langhian-Serravallian limy mudstones-calciturbidites and debris flows, overlain by Tortonian coarse-grained fan-delta deposits. The gravity induced character of most of this progradational wedge implies a progressive uplift of the hinterland.

Abstract The kinematic and structural evolution of the major structures affecting the Çankırı Basin, central Turkey, has been deduced from a palaeostress inversion study. Four palaeostress tensor configurations indicative of four-phase structural evolution have been constructed from the fault slip data collected from the Çankırı Basin. The first two phases indicate the dominant role of thrusting and folding, and are attributed to the collision between the Pontides and the Taurides, the proposed interface of which is straddled by the Çankırı Basin. Phase 1 occurred in the pre-Late Palaeocene and Phase 2 in the Late Palaeocene-pre-Burdigalian. The third phase is dominated by extensional deformation in the Middle Miocene. The latest phase has been active since then and is characterized by regional transcurrent tectonics.

Abstract The well-known Cenozoic Aegean extensional regime, initiated at c. 25 Ma, thinned the crust so that most of it now lies submerged. North of the western continuation of the North Anatolian Fault the Aegean extensional regime is present in central and southern Bulgaria, northern Greece, Former Yugoslavian Republic (FYR) of Macedonia and eastern Albania. Here the system is exposed on land and offers an opportunity to reconstruct the extensional evolution of the system. The southern Balkan peninsula forms the northern part of the Aegean extensional system; deformation is not as great as in the Aegean, but reconstruction of this part of the extensional regime will provide important constraints on its dynamics. Following a period of arc-normal extension associated with Late Eocene-Late Oligocene magmatism, major lithospheric extension appears have begun between 26 and 21 Ma in northern Greece, involving east-northeast-west-southwest extension east of Mount Olympos, on the Island of Thasos and near Kavala. This period of extension may have been accompanied by a short period of coeval compression north of the arc during Early Miocene time or perhaps a little earlier in the Thrace Basin of northwestern Turkey. Northeast-southwest directed Middle-Late Miocene extension appears to have developed obliquely to the older magmatic arc and migrated northward into southwestern Bulgaria in the Sandanski Graben (and perhaps also into the Mesta and Padesh Grabens) by 16.3–13.6 Ma, and in the Blagoevgrad and Djerman Grabens by c. 9 Ma. Extension in south-western Bulgaria was reorganized by c. 5 Ma and in northern Greece extension on the Strymon Valley detachment fault ended by c. 3.5 Ma, but extension continued on new fault systems. From limited structural and stratigraphic data, it is speculated here that related extension may have also occurred during this time in FYR Macedonia and eastern Albania. This northeast-southwest extension is interpreted to be related to trench roll-back along the northern part of the subduction boundary in the western Hellenides. North-south extension along east-west striking faults in central Bulgaria began only after extension was well underway in northern Greece and the Sandanski Graben of south-western Bulgaria. Within the Sofia Graben, the Sub-Balkan grabens, and grabens to their east, north-south extension began at c. 9 Ma, and may have begun about the same time in the Plovdiv, Zagore and Tundja Grabens of the northern Thracian Basin: north-south extension has continued to the present in these grabens. The cause of the north-south extension is unclear and may be related to trench roll-back along the central part of the subduction zone in the Hellenides, or more local causes of clockwise and counterclockwise rotation of the western Hellenides and western Turkey, respectively. By Late Pliocene time a major erosion surface, the sub-Quaternary surface, was developed over a large area of central Bulgaria creating a major unconformity that marks the beginning of Quaternary deposition in the basinal areas. Many large and small graben-bounding faults in west-central Bulgaria displace this erosion surface and demonstrate the widespread extent of Quaternary north-south extension. North-south extension extended westward, with probably decreasing magnitude, across the older northwest trending graben of southwest Bulgaria (the Simitli and Djerman Grabens) and into eastern FYR Macedonia. During latest Pliocene(?) and Quaternary time, northern Greece developed a complex pattern of northeast-southwest extension associated with northeast to east-west striking right-lateral faults forming transfer faults between more local extensional areas. This system of faults overprinted the older northwest trending extensional faults, such as the Strymon Detachment, and may be related to the propagation of the right-lateral North Anatolian Fault into the north Aegean Sea and formation of parallel faults to its north. These two different tectonic regimes extend into FYR Macedonia, where a third regime of east-west extension in western FYR Macedonia and eastern Albania is present, and where extension may represent the continuation of the east-west extensional regime initiated in Middle-Late Miocene time. Active deformation determined from seismicity and Global Positioning System studies suggest northern Greece, and perhaps southwest Bulgaria and FYR Macedonia, is dominated by north-south extension. This pattern of deformation must have developed as recently as perhaps Late Quaternary time. Except for mountains near the Adriatic Sea all of the mountainous topography in the southern Balkan region may be the result of Miocene-Recent extension.

Abstract To solve a long-lasting controversy on the timing and mechanism of generation of the western Anatolian graben system, new data have been collected from a mapping project in western Anatolia, which reveal that initially north-south trending graben basins were formed under an east-west extensional regime during Early Miocene times. The extensional openings associated with approximately north-south trending oblique slip faults provided access for calc-alkaline, hybrid magmas to reach the surface. A north-south extensional regime began during Late Miocene time. During this period a major breakaway fault was formed. Part of the lower plate was uplifted and cropped out later in the Bozdağ, Horst, and above the upper plate approximately north-south trending cross-grabens were developed. Along these fault systems, alkaline basalt lavas were extruded. The north-south extension was interrupted at the end of Late Miocene or Early Pliocene times, as evidenced by a regional horizontal erosional surface which developed across Neogene rocks, including Upper Miocene-Lower Pliocene strata. This erosion nearly obliterated the previously formed topographic irregularities, including the Bozdağ elevation. Later, the erosional surface was disrupted and the structures which controlled development of the Lower-Upper Miocene rocks were cut by approximately east-west trending normal faults formed by rejuvenated north-south extension. This has led to development of the present-day east-west trending grabens during Plio-Quaternary time.