From mantle to crust: Stretching the Mediterranean

The origin of forces driving the deformation of the continental crust near subduction zones and especially in backarc regions is debated. This work is based on a compilation of SKS fast splitting directions that give an image of flow lines in the mantle around the Mediterranean subduction zones and a comparison with stretching and shear directions in metamorphic core complexes that show the pattern of deformation at the scale of the middle and lower crusts. We find that : (1) the two sets of directions are parallel in the three main backarc regions, namely the Alboran Sea, the Tyrrhenian Sea and the Aegean Sea showing that the lithosphere deforms with the same direction of stretching in the crust and the mantle, suggesting that (2) crustal deformation is mainly driven from below by slab retreat, and (3) the lithospheric fabric is reset within a few millions of years in backarc environments.