The buried Fold and Thrust Belt in Sicily: perspectives for future exploration.

The study region is a part of the Sicilian-Maghrebian Fold and Thrust Belt (FTB), a segment of the Alpine collisional belt, recently described as a result of both post-collisional convergence between Africa and Europe and roll-back of the subduction hinge of the Ionian lithosphere. The region (extending in central Sicily from the Madonie Mountains. to the eastern corner of the Iblean-Pelagian foreland through the impressive NE-SW trending Tertiary clastic and evaporitic range of the Caltanissetta trough) is located in an area where the main thrust system disappears beneath a wedge of deformed Neogene deposits. Earlier studies have neglected the importance of the potential target for hydrocarbon opportunities as well the occurrence of carbonate platform rock bodies at a depth and their tectonic relationships with the deepwater carbonate thrust systems. Due to the poorly known structural and stratigraphic characters of the study area some questions arise: - Is there a thrust pile structurally comparable with the western and eastern Sicily tectonic wedge? - Are there carbonate platform units involved in the belt and what is their depth? - Is the clastic and evaporitic Neogene tectonic wedge filling the Caltanissetta trough so thin to be crossed by oil research boreholes? Stratigraphy and mesostructural analyses, accomplished in the last years, in the frame of the Field Mapping CARG Project, provide new data able to constrain the geological cross-sections.The latter are further calibrated by a deep crustal seismic profile (SI.RI.PRO. Project, scientific leader R. Catalano) recently acquired across Sicily, together with refraction seismic, gravimetry and magnetotelluric data. It has strongly improved the knowledge of the deep crustal characters beneath the central Sicily. The recognized deep geometries and the presumed Moho location represent a strong control of the surface geological setting. The results obtained illustrate the foreland forming a steep regional monocline underlying a thickened carbonate thrust wedge to the north and the Gela Nappe to the south, allowing a correlation between outcropping and buried carbonate units, and evidencing the structural relationships between shallow and deep water carbonate units. The reconstruction of the pattern and timing of deformation will be able to propose a kinematic model useful for exploration strategies.