Tectonostratigraphic evolution of the Upper Cretaceous–Cenozoic central Anatolian basins: an integrated study of diachronous ocean basin closure and continental collision

The Upper Cretaceous–Mid-Eocene Kırıkkale, Tuz Gölü, Haymana and Çankırı basins are bounded by the Pontide (Eurasian) continental margin to the north, the Niğde–Kırşehir microcontinent to the east and the Tauride–Anatolide continental unit to the south. The basins developed during northward subduction/collision of the İzmir–Ankara–Erzincan Ocean (‘northern Neotethys’) in the north and the inferred Inner Tauride Ocean in the south. Subduction of the İzmir–Ankara–Erzincan Ocean resulted in latest Cretaceous collision of the Niğde–Kırşehir microcontinent with the Pontide active margin and ophiolite emplacement. Some mid-ocean ridge-type oceanic crust remained to the SW and formed the basement of the Kırıkkale and Tuz Gölü basins. These basins are partially floored by an accretionary wedge to the west and by the Niğde–Kırşehir microcontinent to the east. Locally volcaniclastic, the sediment infill switched to terrigenous after latest Cretaceous. The Haymana Basin, further NW, developed as a forearc basin on the Mesozoic accretionary wedge and Pontide continental fragments. The Çankırı Basin also developed on an accretionary wedge, bounded by the Eurasian active margin to the north. An extensional setting prevailed during the latest Cretaceous related to subduction of remnant oceanic crust, followed by a switch to regional compression during Late Paleocene–Mid Eocene progressive and diachronous collision.