Episodic back-arc extension during restricted mantle convection in the Central Mediterranean

In the Central Mediterranean, during the last 80 Myr Africa has been slowly converging toward Eurasia, with an average relative velocity of less than 1 cm yr(-1). For 50 Myr this slow convergence led to the build-up of the Al pine orogenic belt and to the initiation of consumption of the former Tethy s ocean; in the last 30 Myr, however, the whole Central-Western Mediterrane an has been swept by rapid episodes of trench migration (up to 6 cm yr(-1)) and back-are opening, which consumed the whole former Tethys ocean. We com bine plate tectonic history, geological timing, and laboratory modelling to reconstruct the subduction history and the evolution of the Central Medite rranean over the last 80 Myr. We find that the dynamic evolution of the sub ducting oceanic lithosphere can reconcile the rapid, episodic back-are migr ation with the slow African convergence, but only if the subduction process is restricted to the upper mantle. (C) 2001 Elsevier Science B.V. All righ ts reserved.