LATE MIOCENE TO QUATERNARY STRUCTURAL EVOLUTION OF THE LAMPEDUSA ISLAND OFFSHORE

The Pelagian Archipelago (Lampedusa, Lampione and Linosa islands) rests within a complex geodynamic context characterized by the simultaneous interaction of two apparently in contrast tectonic processes: the convergence along the Apennine-Maghrebian accretionary wedge and the late Miocene-early Pliocene rifting in the Sicily Channel. Through recently acquired, high-resolution single-channel seismic reflection profiles (Sparker System), an updated interpretation of the structural setting of Lampedusa Island offshore and its significance in the regional tectonic scenario has been performed. Late Miocene-early Pliocene rift structures control the tectonic evolution of the Lampedusa plateau, with the development of graben and half-graben basins, filled with syn-rift deposits, in most of the offshore area. In particular, two systems of normal faults in the Lampedusa offshore have been recognized. The master extensional faults, oriented WNW-ESE, represent the main structural alignment of the Lampedusa offshore, reflecting the extensional trend of the Sicily Channel. The second order extensional faults, orientated NNW-SSE, bound smaller pull-apart basins probably associated with the main dextral-transtensive regional regime. The observed tectonic fabric of the Lampedusa plateau is in agreement with the geodynamic features of the area, consisting of a regional extensional regime in a dextral-transtensive zone, marked by extensional and pull-apart basins. More in particular, a different distribution of the syn-rift wedges in the various sectors of the Lampedusa plateau has been identified. It shows that extensional faults terminated their activity in late Miocene in the southern sector, whereas they were active until at least the early Pliocene in the northern one. Furthermore, the tectono-stratigraphic analysis here presented has allowed the identification of the offshore continuations of structures cropping out on land, such as the Cala Creta and the Punta Muro Vecchio normal faults.