Lateral slab deformation and the origin of the western Mediterranean arcs

摘要: [1] The western Mediterranean subduction zone (WMSZ) extends from the northern Apennine to southern Spain and turns around forming narrow tight Calabrian Gibraltar Arcs. The evolution of WMSZ is characterized by a first phase orogenic wedging followed, 30 Ma on, trench retreat back-arc extension. Combining new previous geological data, tomographic images mantle, plate kinematics, we describe during last 35 Myr. Our reconstruction shows that two arcs form fragmentation 1500 km long in small, slabs. Once formed, these slabs outward, producing extension large scale rotation flanks, shaping arcs. Arc formed middle Miocene, while later, late Miocene-Pliocene. Despite different paleogeographic settings, mechanism rupture backward migration presents similarities on both sides Mediterranean, suggesting slab deformation also driven lateral mantle flow particularly efficient restricted (upper mantle) style convection.