3D modelling of the Sorbas Basin (Spain): New constraints on the Messinian Erosional Surface morphology

• 3D modelling of the Sorbas Basin confirms the occurrence of the Messinian Erosional Surface.
• Tectonic shortening during the Pliocene induced a gravitational sliding deformation on top of the Messinian gupsyum.
• We suggest that the Messinian river system developed during the Crisis exited the basin toward the south and the Níjar-Carboneras basin.

The scenario of the Messinian Salinity Crisis (MSC) remains one of the most debated topics in the Mediterranean realm and especially in the Sorbas Basin, which is one of the type-localities of MSC-related deposits. After a recently improved chronostratigraphic framework of the Miocene and Pliocene deposits of the basin, this work is an attempt to image the morphology of the Messinian Erosional Surface (MES) at depth. We built a basin-scale 3D-model of the Miocene and Pliocene series that confirms the erosional character of the Messinian/Pliocene boundary, solving a long-standing and debated question. We tentatively also suggest that the fluvial system developed during the peak of the MSC was exiting the basin toward the south. This new geometrical model, showing a robust internal consistency, can be used as a basis for interpreting the Messinian Salinity Crisis in other sedimentary basins around the Mediterranean Sea. The return of marine conditions in the Early Pliocene on an erosional surface interferes with the continuous formation of the Sorbas Basin asymmetrical syncline, subsidence of the hinge, uplift of the limbs and gravitational sliding. The irregular shape of the MES is superimposed in the southern part of the basin by small-scale box-type folds with two oblique NNE–SSW and WNW–ESE fold axes directions. The architecture of these folds suggests gravitational sliding of post-evaporitic marine sediments during the progressive deformation of the basin during the Zanclean.