The age of the oceanic accretionary wedge and onset of continental collision in the Sicilian Maghrebian Chain.

New biostratigraphic data from the formations unconformably lying above the tectonic units resulting from the Fysch Basin Domain (FBD) in the Sicilian Maghrebids are here reported. The FBD constituted a southern branch of the western Tethys, separating during the Jurassic to Paleogene a Mesomediterranean Microplate from the African Plate. The age of the youngest sediments involved in the nappes and that of the unconformable terrains deposited in thrust-top basins on these tectonic units, allow to define both the age of deformation of the oceanic realm and the onset of the continental collision. The deformation migrated from internal to external areas of FBD starting from the latest Burdigalian-Langhian to Serravallian. Therefore, the previously proposed Eocene-Oligocene mesoalpine deformation of the Maghrebian FBD cannot be supported. The continental collision started during the Serravallian and it was accomplished in the late Tortonian, when clastic deposits sealed the boundaries of the tectonic units originated from all the paleogeographic domains of the Maghrebian Chain. The steps of the tectonic evolution in the Sicilian Maghrebids are now very well constrained and the proposed tectonic evolution may be extended to the whole Maghrebian Chain, as far as to the western Betic Cordilleras and to the southern Apennines, where most of the tectonic events show highly similar features and ages.