Il contributo dei dati morfologici nella determinazione dello stato di attività di faglie neotettoniche: esempio del versante meridionale dei Monti Nebrodi (Sicilia settentrionale)

Abstract

The results of a morphological study along part of the Mounts Nebrodi southern slope (to the NW of Etna Volcano, in northern Sicily) are used as evidence of recent tectonics along the main structures cropping out in this area. The studied area is part of the Apenninic-Maghrebian mountain chain and is characterized by a NW-SE trending right lateral transcurrent zone. This tectonic system is associated with N-S trending normal faults and S-vergsng E-W stretching thrust faults. This tectonic pattern gave rise to a stepped morphology; "step" surfaces are remnants of an original low-relief energy summit surface developed in a fluvial environment still preserved locally on the top of the highest hills. The slope connecting stepped surfaces are portions of fault scarps. Two generations of fault scarps have been recognized: The older generation is linked with the N-S trending normal faults, the younger with E-W stretching thrusts faults. This evolution is explained by hypothesising that an original transtensional tectonic regime changed to a transpressive regime, latest phases of which continued up to the onset of the Ml Etna volcanic activity in the late Middle Pleistocene.