Paleomagnetic indications of megatectonic movements in the Tethys

The paleomagnetic data obtained in northeast Italy, southern France, and northeast Spain differ considerably and systematically from those for meso-Europe. The deviation of the inclination of the paleomagnetic directions may be explained by assuming that the structural units of Italy, southern France, and Spain have moved westward with respect to meso-Europe. This late Paleozoic, Mesozoic, and Cenozoic westward drift of rigid blocks in the mobile Tethys zone is considered to be due to dextral shear movements, which developed in the Tethys zone during the northwestward drift of the Gondwana shields (Africa, Arabia, and India) and the contemporaneous eastward movement of meso-Europe. The deviation of the declination of the paleomagnetic directions in northeast Italy, Corsica, and northeast Spain are indicative of counterclockwise rotations. These rotations are thought to be related to the dextral shear movements mentioned above. They were caused by subsidiary left lateral shear which developed in the mobile zones bordering the primary dextral faults. Similar structural systems are found in the former Tethys areas of Turkey (Anatolia fault system) and northwest Africa (Atlas fault system). The main conclusion drawn from the paleomagnetic data is that the Tethys mobile belt was and still is a zone of primary dextral shear.