oa Salt Tectonics of the Sivas Basin (Turkey): Open-air Museum of Seismic Analogues

The Sivas Basin in Anatolia is likely the world’s finest open-air museum of salt tectonic structures. It is an elongated Oligo-Miocene sag basin that developed in an orogenic context above the complex Taurus-Pontides suture. A mid Oligocene quiet period in an overall continuous convergence history allowed the deposition of a thick evaporite sequence. Erosion of the Taurides shed clastic sediments and initiated the development of mini-basins and associated evaporite diapirs and walls. The minibasins are filled by Mid-Oligocene to Early Miocene clastics (fluvial silts and sandstones), marls, and lacustrine to marine limestones, the thickness of which may reach 4 kilometres. The stratal architecture along evaporite walls records the progressive subsidence of the minibasins, with strong rotation of beds, unconformities and local reworking of evaporites. Within the basin, the sediments show lateral thickness variations and spectacular angular unconformities. Following this quiet period, compression resumed in Early Miocene, forcing evaporites upward, which led to the formation of overhangs and sheets.