Seismic stratigraphy and structural evolution of the Adana Basin, eastern Mediterranean

The transition from deep water to fluvio-deltaic sedimentation in the early Tortonian recorded the combined effects of a global eustatic sea-level fall and regional tectonic uplift, presumably related to renewed activity in the Tauride orogen to the north. It led to widespread erosion giving rise to a smooth unconformity surface in most of the Adana Basin. The stratigraphic and structural relationships suggest that the onset of east-directed thrusting in the trailing portion of the Misis fold-thrust belt occurred sometime during the lower Tortonian, coinciding with the switch from marine to terrestrial sedimentation. The truncation by this unconformity of the folded-thrusted successions of both Miocene successions across the trailing thrust sheets marks the effect of progressive erosion as the thrust sheets are uplifted above base level. A prominent progressive syntectonic unconformity is developed extending from the region of main thrust culminations westward into the depocentre situated on the backlimb of the leading thrust of the Misis fold-thrust belt. Much of the Tortonian deposition took place within this trailing piggy-back basin and the easterly onlap and the westerly tilt of this succession mark the progressive uplift of the fold-thrust belt during the remainder of the Tortonian. Terrestrial and fluvio-deltaic deposition in the Tortonian was succeeded in the Messinian by the deposition of mixed evaporite-carbonate-clastic succession in the Adana Basin. The base of this succession is a local unconformity across the Tortonian succession that marks the cessation of the fold-thrust activity in the east and ensuing erosion across the fill of the Tortonian piggy-back basin. The subcrop of the Messinian succession marks the edge of deposition in a paleotopographic depression situated between the Tortonian Misis fold-thrust belt in the east and the paleoslope over the front of the reactivated Tauride fold-thrust belt in the north. The western margin of deposition of the Messinian succession was probably controlled by the development of the Kozan Fault zone. Plio-Quaternary subsidence created the accommodation space that allowed rapid delta progradation.