Determination of 3D Paleostress Systems: An Additional Technique for Basin Analysis

H. E. Bakker

The present structure of the western Mediterranean has been largely determined by several phases of rifting and oceanic spreading which began during the Oligocene. The main rifting event took place during the middle Oligocene-earliest Miocene. This is indicated by structural, stratigraphic, metamorphic, and volcanic data. During this event Corsica and Sardinia drifted eastward from the previously amalgamated Iberian-European plate, and the Provencal and Algerian basins were developed.

The plate movements related to the development of these basins have been reconstructed by using the orientation of the present plate boundaries, the strike of transform faults, the age and trend of magnetic anomalies, and paleomagnetic data.

An additional approach is proposed, based on detailed field study of faults at specific locations on the continental plates. From fault-plane and slip-direction data we can calculate the responsible 3D paleostress systems. These stress systems apparently can be used to reconstruct in detail the kinematics of the rifting and drifting processes on both a local and regional scale. The method is illustrated by the geodynamic evolution of Mallorca, Menorca, and the Gulf of Valencia.

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