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