TECTONIC HISTORY OF THE SUBMERGED MAGHREBIAN CHAIN FROM THE SOUTHERN TYRRHENIAN SEA TO THE PELAGIAN FORELAND

A description is given here of the structure and tectonic evolution of the submerged NW-SE trending Alpine belt extending from the Sardinia Channel across the Sicily Straits to the Pelagian Sea. This mainly results from re-interpretation of the existing seismic network. In the Sicily Straits the crust comprises an allocthonous belt composed of Tertiary flysch-type thrust slices stacked in an imbricate wedge. The wedge is composed of Mesozoic basin and platform carbonates thrusts derived by deformation of the old Sicilian continental margin. Lower Miocene to Lower Pleistocene foredeep deposits (terrigenous and elastic carbonates) filled progressively onlapping foreland basins during regional compression. In the southern Sicily offshore the deformation spanned early Miocene to early Pleistocene time. The structural evolution of the Gela foredeep shows the kinematics and timing of emplacement of the 'Gela Thrust System', that is believed to be the present-day thrust front of the Sicilian accretionary wedge. In the Sicily Channel, the Plio-Pleistocene tectono-sedimentary history of the Lampedusa-Linosa sector reveals evidence of middle Pliocene extensional tectonics, and indicates a rift mechanism for formation of the Sicily Channel. This event was followed by inversion tectonics and strong vertical tectonics in the late Pleistocene.