Adria/Europe Collision Effects

Zoltan Balla

In the Senonian, the Adriatic promontory of the African plate lay between two transform faults which joined the north-vergent Alpine-Carpathian front with the south-vergent Apenninic and Hellenic fronts. In the late Eocene it collided with the European continent.

The head of the promontory was crushed by compression in the Oligocene and lengthened in a west-east direction. This initiated formation of the West Alpine and West Carpathian arcs. A bay of thin European crust in the area now occupied by the Carpathians facilitated a more pronounced advance of the eastern arc. A wedge-shaped body with the Bakony Mountains in its rigid core was pressed out from the Alpine region. The Eastern Alps and the West Carpathians as well as the Southern Alps and the middle Pannonian units suffered sinistral and dextral shear, respectively, which resulted in their lengthening and zonality.

In the early-middle Miocene the Adriatic promontory was broken up. Its northern part suffered counterclockwise rotation in connection with the opening of the Ligurian Sea while the southern part only shifted relative to Africa. Rotation of the northern microplate forced the Dinaric-Hellenic arc to change its shape from convex to concave, and the intra-Carpathian units advanced toward the northeast and rotated toward each other. This completed the Carpathian arc and initiated subsidence in the Pannonian basin.

Since the late Miocene the Adriatic promontory has acted again as a part of Africa with a maximum 60-km shift toward the west, caused by the escaping Turkish microplate.

AAPG Search and Discovery Article #91032©1988 Mediterranean Basins Conference and Exhibition, Nice, France, 25-28 September 1988.