Geological Map of the Rocca Busambra-Corleone region (western Sicily, Italy): explanatory notes

Abstract

The geology of the Rocca Busambra-Corleone region, in centralwestern Sicily, is relevant to the understanding of the central sector of the Maghrebian-Sicilian fold-and-thrust belt. In the investigated area Mesozoic shallow- and deep-water carbo - nate deposits pertaining respectively to the Trapanese and the Sica - nian successions, and a thick Oligo-Miocene numidian flysch body, crop out. Minor outcrops of Cretaceous-Palaeogene Sicilide complex and syn-orogenic deposits of the Late Serravallian-Early Messinian Castellana Sicula and Terravecchia formations are also present. A structural analysis reveals complex tectonic relationships between the Trapanese carbonate platform tectonic unit (the Rocca Busambra carbonate ridge) and the overthrusting Sicanian deepwater carbonate (Corleone-Barracu) and numidian flysch tectonic units, outcropping around the carbonate ridge. In this tectonic frame Rocca Busambra is a 15 km long, E-Wtrending large antiform, slightly rotated to the NW-SE on its eastern limb (Pizzo Marabito). The unit forms a southerly verging ramp structure; it is bound, to the south, by E-W and WNW-ESE striking major reverse faults and, to the north, by the E-W striking Busambra fault, that is a back-verging reverse fault characterized by right-handed strike-slip component of movement. The Busambra carbonate platform tectonic unit, that appears to have been thrust up to the surface, is reimbricated above the Sicanian deep-water carbonate and numi - dian flysch tectonic units; these, in turn, are redeformed. The latter tectonic event overprinted the original tectonic relationships and took place during the Late Pliocene, as evidenced in adjacent regions