Age refinement of the Messinian salinity crisis onset in the Mediterranean

We propose a revised age calibration of the onset of the Messinian salinity crisis (MSC) in the Mediterranean based on re-analysis of two “classical” sections: Perales (Sorbas basin, Spain) and Monticino (Vena del Gesso basin, Italy). The main novelties are recognition of an extra gypsum cycle in the transitional interval of the Perales section and the revision of the magnetostratigraphy in the Monticino section. We show that the first primary gypsum bed is located three precessional cycles above the C3r/C3An magnetic reversal, correlating to the summer insolation peak at 5.969 Ma; consequently we place the MSC onset in the preceding flexural point in the insolation curve at 5.971 Ma. Accordingly, we suggest that the MSC onset was preconditioned by the reduction of the hydrological exchanges with the Atlantic ocean and was finally triggered by glacial conditions in the northern hemisphere and by arid conditions in northern Africa.