Thrust tectonics in the central part of the External Hellenides, the case of the Gavrovo thrust

Résumé

Thrust faulting plays an important role in the structural deformation of Gavrovo and Ionian zones in the central part of the ‘External Hellenides’ fold-and-thrust belt. The Skolis mountain in NW Peloponnese as well as the Varassova and Klokova mountains in Etoloakarnania are representative cases of ramp anticlines associated with the Gavrovo thrust. Surface geology, stratigraphic data and interpretation of seismic profiles indicate that it is a crustal-scale thrust acted throughout the Oligocene time. It is characterized by a ramp-flat geometry and significant displacement (greater than 10 km). Out of sequence thrust segmentation is inferred in south Etoloakarnania area. Down flexure and extensional faulting in the Ionian zone facilitated the thrust propagation to the west. The thrust emplacement triggered halokenetic movement of the Triassic evaporites in the Ionian zone as well as diapirisms that were developed in a later stage in the vicinity of the Skolis mountain.