Structural inheritance, growh and dissection in a fold-and-thrust belt: a case from western Lucania, southern Italy

In this contribution we anticipate the results of a structural investigation carried out along the central sector of the Apennines fold-and-thrust belt of western Lucania, southern Italy. The data inferred from this study made it possible to reconstruct the complete deformation history of the central province of the southern Apennine belt, where documentation of well-constrained deformation episodes is integrated with recognition of previously unreported structures. The study area is located between the Melandro and Agri valleys, and comprises the villages of Savoia di Lucania, Vietri di Potenza, Marsico Vetere and Viggiano. From Late Miocene time onwards thrusting was followed bythe onset of extensional deformations that overprinted contractional structures and migrated progressively towards the front of the belt. The most recent structures related to the extensional episode are high-angle normal faults that are clearly visible along the northeastern edge of the Agri Valley. These faults are replaced to the south by left-lateral strike-slip faults, analogue to those described at the Lucania-Calabria boundary. High-angle normal faults truncate and offset at least two older generations of tectonic contacts, that dip at moderate to low angles producing mainly extensional displacements. At odds with older thrusts and with more recent high-angle normal faults, the kinematics of these low-angle tectonic contacts is not always well-constrained, and thus their tectonic significance remains problematic. Observations carried out in the northern edge of the Agri valley strongly support the hypothesis that these contacts are, in fact, low-angle normal faults, although a thrust origin for analogue structures found elsewhere in the investigated area cannot be ruled out.