Abstract

The formation of small fragments of continental lithosphere, which rift away from a passive margin and are carried toward a trench together with the surrounding oceanic crust, is a characteristic of many collisional settings, in particular of the northern margin of Gondwana during the Mesozoic. This motion, though chaotic in appearance, can be described rigorously in terms of plate kinematics driven by local temporal variations in the relative velocity field between the main colliding plates. In this model proposed here, the rifted continental fragments approach the trench with the same stationary velocity as the oceanic lithosphere in which they are embedded, while the spreading centers that separate these microplates from the rifted continental margin, either speed up or slow down in order to compensate for small variations of the velocity field between the major colliding plates. Hence, the oceanic leading edge of a subducting plate may separate from its continental part and move independently to ensure a constant convergence rate at the trench. The application of this principle to the complex tectonic history of the Mediterranean region during Jurassic and Cretaceous times is performed starting from a revised global plate motion model. A set of maps illustrating the regional velocity and acceleration fields is presented for nine major phases from the Bajocian through the Maastrichtian. These maps provide new constraints that may be helpful for the construction of plate tectonic models of the Tethyan realm. New insights into some of the major tectonic events that occurred during the Jurassic and the Cretaceous in the Mediterranean region are gained from the correlation between kinematic events and geologic evidence.

Keywords: Mediterranean region, Plate tectonic modeling, Plate kinematics, Neo-Tethys, Adria, Collisional tectonics.