Post-late miocene kinematics of the adria microplate: inferences from geological, geophysical and geodetic data

Abstract

The space-time distribution of deformation in the central Mediterranean area suggests that the Adriatic domain (Adria) has moved coherently w~thA frica up until the late Miocene and that, subsequently, it decoupled fiom Africa (Nubia) and undenvcnt a clockwise (CW) rotation with respect to Eurasia. This event was determined by the wcstward push of the Anatolian- Aegean-Balkan system, after its collision with the southern Adriatic continental domain. The CW rotation of the Adria microplate induced a strong compressional regime in the central Mediterranean region, which can account for the major tectonlc events that occurred in this zone since the late Miocene. These include the renewal of accretionary activity in the Apenninic belt, the opening of the central Tyrrhenian basin, the detachment of the lblean microplate from mainland Africa and the development of a major fracture in the northern Adriatic foreland. The CW rotation of the Adria plate came to an end around the late Pliocene-early Pleistocene due to the collision of the Adria continental domain with the Southern Apennines. After this event, Adria has undergone a slow CCW rotation with respect to Eurasia. This kinematic pattern during the last evolutionary phase is suggested by the distribution of Quaternary deformation in the peri-Adnatic zones, in particular the shortening recognized at the eastern (Dinarides-Hellenides) and northern (southern Eastern Alps) boundaries of Adria, and is consistent with the seismological and geodetic evidence in the Adriatic and peri-Adriatic regions. No significant recent deformation can be recognized between Adria and Africa, at the Plioccnc decoupling zone or at any other possible decoupling tectonic belt. This suggests no, or at most very littlc, rclative motion bctwcen thew two doma~ns during the Quaternary. Tlic possible implications of this last evidence on Nubia-Eurasia kinematics are discussed.