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

Luca Basilone(*)
(*) Dipartimento di Geologia e Geodesia, Università di Palermo, Via Archirafi, 20-22 - 90123 Palermo. lucabasilone@unipa.it

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 carbonate deposits pertaining respectively to the Trapanese and the Sicanian 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-Barracù) and numidian flysch tectonic units, outcropping around the carbonate ridge. In this tectonic frame Rocca Busambra is a 15 km long, E-W trending 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 numidian 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.

Western Sicily, geological survey and mapping, Mesozoic shallow- and deep-water carbonate successions, tectono-stratigraphic setting, Meso-Cenozoic deformational history.