Geology of the Kumeta-Pizzuta ridges (NW Sicily)

Abstract

We present a 1:25.000 scale geological map of the Kumeta-Pizzuta ridge in north western Sicily (Italy), which was achieved by integrating stratigraphic, structural and geophysical data. In this area the tectonic edifice results from the piling-up of deep water-, carbonate platform- and pelagic platformderived tectonic units (Imerese and Sicilide, Panormide and Trapanese domains respectively) originated by deformations of former southern Tethyan continental margin. The structural setting shows interference of subsequent tectonic events, different type of structural styles, and different-scale deformational patterns. Early overthrust of the Imerese on the Trapanese units (since late Serravallian) was followed by wedging at depth of the Trapanese units (after Tortonian). The wedging implied re-embrication and shortening into the overlying Imerese Units and produced main folding and compressive to transpressive structures along the Kumeta-Pizzuta Ridge. Seismic reflection profiles image the main E-W trending anticlines have been offset by high angle reverse to transpressive faults that merge at depth with low angle, regionally widespread, flat decollement surfaces that show, in this sector, a northward tectonic transport. This setting supports backthrusting along transpressional faults in the study area, ruling-out that the Kumeta ridge is a positive flower structure related to a near-vertical deep, crustal, shear zone as formerly suggested