Geophysical investigation of the crust of the Upper Adriatic and neighbouring chains

Abstract

The Adria domain and the neighbouring chains (Alps, Apennines, Dinarides) are presented with images and interpretative models indicating their main crustal characteristics as revealed by the geophysical prospecting (gravity, receiver functions, wide-angle seismic and near vertical reflections). The collision with the adjacent blocks has implied deformations of the lower crust and of the crust–mantle boundary with accretionary wedging of slabs of lithosphere, entire crust or upper crust, respectively. The position of the main decoupling levels within the subducting lithosphere like the Sub Tauern Ramp in the Eastern Alps is the key parameter for the post-collision evolution. Decoupling levels at the top of the lower crust or at the base of the upper crust also might have played a dominant role in the orogenic movements controlling the present-day crustal architecture. According to the recent acquisitions a triple junction among Adria, Pannonian and European crusts is proposed near Katschberg, at the eastern edge of the Tauern Window, with Pannonian acting as upper plate in the collision with Europe and with Adria: Europe underthrusts Adria and Pannonian and Adria underthrusts Pannonian fragments. Finally, Adria underthrusts the Apennines along the western side of the Adriatic Sea. The paper revisits the geophysical data (mainly reflection and refraction seismic) to evidence resolution and penetration limits in the exploration of crustal structures.