Geodynamics of SW-Pannonian inselbergs (Mecsek and Villány Mts, SW Hungary): Inferences from a complex structural analysis

Three independent methods: paleomagnetic investigation, analysis of reflection seismic sections and structural study of outcrops have been applied to MesozoicTertiary rocks of the Mecsek and Villány Mts (SW Hungary), which form inselbergs in the southern part of the Pannonian Basin. The structural history is marked by Late OligoceneEarly Miocene NW-SE shortening (in present cooridinates); late Early Miocene N-S shortening together with important clockwise rotations of the whole area and local counterclockwise rotations in E-W left lateral wrench corridors; smaller N-S shortening with local wrenching and positive inversion during the Middle Miocene; an important N-S shortening creating large folds and thrust reactivation in Late Miocene; a transtension characterised by roughly WNWESE elongation directions, creating left lateral oblique faulting along NE-SW oriented fault segments in Late Miocene; an important NW-SE shortening from latest Miocene to Present. This latter reactivated E-W structures as right lateral transpressive wedges and generated locally important rotations along them. Comparison of the obtained and regional structural data and rotation pattern strongly modifies our original concepts about microplate behaviour in the Intra-Carpathian realm. The geodynamic history is still dominated by the opposite rotation and consequent interplay of two major terranes: Alcapa and Tisza, but these are no more considered as rigid blocks. Differential rotations and deformations within Tisza are explained by major tears or thrusts across this block. Left lateral wrench zones within the clockwise rotating Tisza block are explained by differential movements due to this rotation. Both paleomagnetic and structural data indicate that the main phase of rotation and complex deformation was in Late Ottnangian (ca. 18 Ma), followed by a more quiescent period in this part of the Pannonian Basin. Several strong reactivations, perhaps with incipient rotation, are experienced from Late Miocene (ca. 11,5 and ca. 7 Ma) on. Correspondence to: L. Csontos ([email protected])