Mantle dynamics in the Mediterranean

Abstract

TheMediterranean offers a unique opportunity to study the driving forces of tectonic deformation
\nwithin a complex mobile belt. Lithospheric dynamics are affected by slab rollback and collision of two large,
\nslowly moving plates, forcing fragments of continental and oceanic lithosphere to interact. This paper reviews
\nthe rich and growing set of constraints from geological reconstructions, geodetic data, and crustal and upper
\nmantle heterogeneity imaged by structural seismology. We proceed to discuss a conceptual and quantitative
\nframework for the causes of surface deformation. Exploring existing and newly developed tectonic and
\nnumerical geodynamic models, we illustrate the role of mantle convection on surface geology. A coherent
\npicture emerges which can be outlined by two, almost symmetric, upper mantle convection cells. The
\ndownwellings are found in the center of the Mediterranean and are associated with the descent of the
\nTyrrhenian and the Hellenic slabs. During plate convergence, these slabs migrated backward with respect to
\nthe Eurasian upper plate, inducing a return flow of the asthenosphere from the back-arc regions toward the
\nsubduction zones. This flow can be found at large distance from the subduction zones and is at present
\nexpressed in two upwellings beneath Anatolia and eastern Iberia. This convection system provides an
\nexplanation for the general pattern of seismic anisotropy in the Mediterranean, first-order Anatolia, and Adria
\nmicroplate kinematics and may contribute to the high elevation of scarcely deformed areas such as Anatolia
\nand eastern Iberia. More generally, the Mediterranean is an illustration of how upper mantle, small-scale
\nconvection leads to intraplate deformation and complex plate boundary reconfiguration at the westernmost
\nterminus of the Tethyan collision.