Dynamic interactions between subduction zones

A common feature of tectonic reconstructions is the migration of subduction zones and their interactions, resulting in complex tectonic patterns. Reduced migration rates, uplift, strong rotations, and slab break-off are all tectonics features commonly associated with convergent margin interactions, showing that while subduction zones' motions fundamentally shape tectonics settings, their interactions hold the key to their complexities. Fundamental properties such as slab buoyancy, dip direction, and coupled mantle flow determine the motions of single hinge zones. When these zones approach, stress transfers between the slabs through the lithosphere and the mantle, thereby altering the subduction force balance, favoring, opposing, or diverting further motions. We illustrate the range of configurations reported in tectonic reconstructions and address their dynamics through the results of analog and numerical models of subduction dynamics in the upper mantle. The Cenozoic evolution of the Mediterranean provides relevant examples of such interactions, where the coeval activity of several subduction zones during the Africa-Europe convergence has strongly overprinted the current tectonics. A comparison of new analog models with the deep dynamics of the Mediterranean shows how the interactions among slabs and mantle may have shaped the distribution of basins and mountain belts, their uplift, and volcanism in this tectonic province.