Cenozoic tectonic evolution of the Ecemis fault zone and adjacent basins, central Anatolia, Turkey, during the transition from Arabia-Eurasia collision to escape tectonics

The effects of Arabia-Eurasia collision are recorded in faults, basins, and exhumed metamorphic massifs across eastern and central Anatolia. These faults and basins also preserve evidence of major changes in deformation and associated sedimentary processes along major suture zones including the Inner Tauride suture where it lies along the southern (Ecemis) segment of the Central Anatolian fault zone. Stratigraphic and structural data from the Ecemis fault zone, adjacent NE Ulukisla basin, and metamorphic dome (Nigde Massif) record two fundamentally different stages in the Cenozoic tectonic evolution of this part of central Anatolia. The Paleogene sedimentary and volcanic strata of the NE Ulukisla basin (Ecemis corridor) were deposited in marginal marine to marine environments on the exhuming Nigde Massif and east of it. A late Eocene-Oligocene transpressional stage of deformation involved oblique northward thrusting of older Paleogene strata onto the eastern Nigde Massif and of the eastern massif onto the rest of the massif, reburying the entire massif to >10 km depth and accompanied by left-lateral motion on the Ecemi§ fault zone. A profound change in the tectonic setting at the end of the Oligocene produced widespread transtensional deformation across the area west of the Ecemis fault zone in the Miocene. In this stage, the Ecemis fault zone had at least 25 km of left-lateral offset. Before and during this faulting episode, the central Tauride Mountains to the east became a source of sediments that were deposited in small Miocene transtensional basins formed on the Eocene–Oligocene thrust belt between the Ecemiş fault zone and the Niğde Massif. Normal faults compatible with SW-directed extension cut across the Niğde Massif and are associated with a second (Miocene) re-exhumation of the Massif. Geochronology and thermochronology indicate that the transtensional stage started at ca. 23–22 Ma, coeval with large and diverse geological and tectonic changes across Anatolia.