Seismic anisotropy and deformation patterns in upper mantle xenoliths from the central Carpathian-Pannonian region: indications for a collision driven asthenospheric flow?

The Cenozoic geodynamic evolution, including basin formation, volcanism in the Carpathian-Pannonian region (Central Europe, CPR for short), has been interpreted in many different ways. A review is presented on deformation patterns in mantle xenoliths from the central part of the Carpathian-Pannonian region and seismic anisotropy data which appear to support the existence of an E-W directed asthenospheric flow underneath the study area. The E-W oriented asthenospheric flow and accompanying horizontal extrusion of lithospheric blocks from the Alpine orogen, as well as extension was the result of the collision between the European and Adriatic units in the Eocene. The eastward directed asthenospheric flow may be an additional driving force to the previously proposed slab-rollback and gravitational instability models for the formation and deformation of the Carpathian-Pannonian region. The existence of such a flow beneath the CPR may also generally confirm that the asthenosphere does not only have a passive role in tectonically active zones (i.e., orogen belts) but can be an important driving-force for the formation of marginal basins.