PTOLEMAIS BASIN - THE TECTONIC ORIGIN OF A SENONIAN MARINE BASIN UNDERNEATH THE SOUTHEASTERN MEDITERRANEAN-SEA

The large Litani anticline, that was recently discovered in the SE Med iterranean basin, sheds new light on the regional tectonic history of the Levant in the late Cretaceous. The anticline is buried under 5 km of undeformed sedimentary series, its apex was leveled by erosion, and its folding can be dated to the early Senonian. The seismic reflectio n data suggest that shortly after the structural development of the an ticline in a shallow marine environment and under compressional stress es, the regional tectonic regime turned extensional, and the anticline subsided into the open marine environment of Ptolemais basin. That su bsidence can be dated to the Senonian as well. It is suggested that th e Litani anticline is a part of the Syrian Arc, and its deformation an d subsequence subsidence reflect the complex tectonic regime of southe rn Anatolia, where the continental collision with Arabia and the subdu ction of the Neo-Tethys oceanic crust took place concurrently. The Lit ani anticline and the Ptolemais basin thus show that contrasting tecto nic regimes and their structural derivatives could evolve at a very fa st rate.