Abstract Central and Western Anatolia form a continental back-arc region related to the Hellenic-Cyprus convergent plate boundary of the Anatolian and African Plates. The Akşehir-Afyon Graben (AAG), the easternmost extension of the west Anatolian horstgraben system, is located at the junction of Central Anatolia and eastern limb of the Isparta Angle. The AAG is 4–20 km wide and 90 km long. It trends west-northwest-east-southeast and is an actively growing rift containing two sedimentary infills of continental fluviolacustrine origin bounded on both sides by oblique-slip normal faults. The older infill is folded, thrust faulted and early Late Miocene in age. The younger infill, which is nearly horizontally bedded, is Plio-Quaternary in age and rests on the older infill with angular unconformity. The deformation of the older infill and the angular unconformity indicate a Late Miocene phase of compression, which separates two extensional periods. The second phase of extension has lasted since the Pliocene and is part of the current extensional neotectonic regime of both west Central Anatolia and the Isparta Angle, despite being previously reported as a compressional neotectonic regime. The graben-bounding Akşehir Fault Zone (AFZ) and the Karagöztepe Fault Zone display well-preserved fault surfaces and slickenlines. Although stereographic plots of the fault slip data show that the graben-bounding structures are oblique-slip normal faults, the AFZ has also been described as a single reverse fault. Both the field and seismic data, particularly the 1921 Argıthanı-Akşehir and 1946 Ilgın-Argıthanı earthquakes, indicate that the AAG is an active neotectonic structure. However, it can also be interpreted to lie in a seismic gap when its rate of seismicity is compared with that of the Gediz-Simav Graben forming its west-northwestern extension.

Abstract The Plio-Quaternary Eşen Çay Basin is situated at the junction of Hellenic and Cyprus arcs in southwestern Turkey. The basin is important for understanding the tectonic evolution of the region in relation to the Hellenic and Cyprus arcs. Fault data from unconsolidated Pliocene and Quaternary deposits, as well as from pre-Pliocene lithologies, are analysed in order to reconstruct the evolution of the stress field evolution from Pliocene onwards. Inversion of measured fault slip vector data identifies two main stress states: extensional and strike-slip. Both states are characterized by a NE–SW-trending minimum horizontal stress axis (σ Hmin =σ 3 ). The mean R value is 0.67, indicating a triaxial state of stress. The inversion also indicates the existence of extensional and strike-slip faulting characterized by a NW–SE-trending σ 3 axis. This indicates a change in the direction of the minimum horizontal stress axis (σ 3 ) from a NW–SE-trending σ 3 that dominated prior to Quaternary to a NE–SW-trending σ 3 that dominated during Quaternary up to actual time.

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.

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.