GNGTS 2013 - Atti del 32° Convegno Nazionale

Morphological evidences of tectonic tilting in NE Sicily F. Pavano Dipartimento di Scienze Biologiche, Geologiche ed Ambientali, Università degli Studi di Catania, Italy Introduction. The NE-Sicily, the southern termination of the Calabrian arc, represents a discrete crustal mobile block ( PMB - Peloritani Mobile Block; inset in Fig. 1a) diverging towards the NNE from the rest of the Sicilian collision zone and moving independently from rest of the Calabrian arc (Hollenstein et al. , 2003; D’Agostino and Selvaggi, 2004). The marine terraces analysis suggests that this crustal block, since the Middle-Pleistocene (~600 ka) experienced a homogeneous uplift constraining a long-term uplift-rate of about 1.1 ± 0.13mm/a, respect to the 0.76 ± 0.05 mm/a measured for the surrounding areas. This change in uplift-rate is accommodated, to the SW, by several NW-SE-oriented normal fault segments, showing rejuvenated fault scarps and providing a short-term vertical displacement-rate of about 0.4-0.5 mm/a. In correspondence of the south-western portion of the PMB a drainage system analysis has been carried out in order to recognized the morphological effects due to local tectonic deformation occurred along the NW-SE oriented faulted belt. Several morphometric features of fluvial network and drainage basins, like basins lateral asymmetry, fluvial hierarchical anomalies and drainage system arranging, have been analyzed. The results of these analysis, show that, since the Middle-Pleistocene, the southwestern portion of PMB , underwent a NE- ward tectonic tilting, complying and geomorphometrically confirming the NW-SE oriented, SW-dipping, normal faults activity. Tectonic and seismotectonic setting. The NE Sicily is located at the southern termination of the Calabrian Arc, at the intersection between the Neogene Sicilian collision belt and the incipient Siculo-Calabrian Rift Zone ( SCRZ – Catalano et al. , 2008) (Fig. 1a). The NE Sicily represents an orocline that during the Neogene-Quaternary age has been involved in two main stages of deformation. During the first one, the Calabrian Arc experienced a lateral extrusion towards to the south-east (Boccaletti et al. , 1990), accommodating the hinge retreat of the Ionian slab. This process caused the development of a wide system of NW-SE and WNW- Fig. 1 – a) Seismotectonic sketch map of Sicily and southern Calabria, displaying the main Quaternary tectonic features and their relationships with plate boundary. The inset shows the location of the PMB (Peloritani Mobile Block); b) Active tectonics and Pleistocene deposits at the SW margin of PMB. The inset shows the absolute elevation (m a.s.l.) of the marine terraces recognised in this area. 176 GNGTS 2013 S essione 1.2