Sedimentary development of the Oligocene Karsantı Basin, southern Turkey, in its regional tectonic setting

• The Karsantı Basin is infilled with Oligocene sediments, in an inferred extensional intermontane setting.
• Alluvial fan, shallow marine, lacustrine and fluvial facieses determined in the basin deposits.
• Basin was evolved in a intermontane setting and deposition controlled by half graben tectonics.
• Palaeontological determinations indicates the age of the Karsantı Basin as Oligocene.
• Lack of Palaeocene–Eocene units may imply a regional uplift around the basin.

Following Late Cretaceous ophiolite and melange emplacement within the Tauride belt several Neogene sedimentary basins of variable size were formed along the southern flank of the Taurus continent in southern Turkey. These include the Pozantı and Karsantı Basins and the regional scale Çukurova Basin Complex, extending southwestwards into the Cilicia-Kyrenia Basin. The Karsantı Basin is bounded by the regional scale sinistral Ecemiş Fault Zone to the west, the East Anatolian Fault Zone to the southeast and the Negoene Adana Basin to the south. Deformed Palaeozoic and Mesozoic rock units that display an irregular palaeotopography form the basement of the Karsantı Basin. These units are overlain by an allochthonous Kızıldağ melange and by thrust slices of basic/ultrabasic ophiolitic rocks (Faraşa ophiolites) that were emplaced in this region during the Late Maastrichtian. The Karsantı Basin was formed during the Oligocene above the thrust sheets. The Karsantı Basin disconformably overlies the ophiolitic nappes and is interpreted as a N–S trending half graben which was probably most active following the deposition of lacustrine sediments during the late Oligocene. The main Karsantı Basin infill is represented by four lithological units: 1. Alluvial fan deposits (A1), 2. shallow-marine deposits (A2), 3. lacustrine deposits (A3), and 4. fluvial deposits (A4). These sediments were deposited during the Oligocene, prior to the initiation of the main Adana Basin, which formed in a separate intermontane setting. The Karsantı Basin fill is unconformably overlain by early Miocene sediments of the Neogene Adana basin.