Major evidence on the driving mechanism of the Tyrrhenian Apennines trench-arc-back arc system from CROP seismic data

The results of deep seismic reflection exploration in the central Mediterranean region (CROP Project) provide basic insights into the driving mechanism of the Tyrrhenian-Apennines arc-trench-back are system. In particular, such information clearly indicates that during the formation of the Tyrrhenian back arc basin the migrating orogenic wedges (Arc) and the Adriatic domain underwent strong shortening, that is not consistent with the implications of the driving mechanism which is generally invoked to explain the formation of the Tyrrhenian basin, that is the gravitational sinking of subducted lithosphere (slab-pull). In this work it is argued that the structural/tectonic features evidenced by the CROP cross sections and the major post-late Miocene tectonic events recognized in the central Mediterranean region can plausibly and coherently be explained as effects of extrusion processes driven by the West to NW ward motion of the Anatolian-Aegean system and the convergence between Africa and Eurasia. The plausibility of the proposed mechanism is also supported by the results of numerical modelling.