GEOLOGIC OUTLINE OF THE TUSCANY-LATIUM CONTINENTAL SHELF (NORTH TYRRHENIAN SEA): SOME GEODYNAMIC IMPLICATIONS

An old high-penetration seismic survey of the Tuscany-Latium continental shelf furnished use­ful information on Neogene stratigraphy, structural setting and paleogeography. The seismically penetrated stratigraphic column is composed of five seismic units which may be correlated with the tectonic and strati­graphic units of the inner Apennine belt, described in the literature. Three tectonically superposed units consti­tute the deformed substratum, transgressively overlain by two postorogenic sedimentary cycles. From the last diastrophic phases onward, the area underwent a very diversified tectono-sedimentary evolution, which gave origin to different structural landscapes. During the Upper Tortonian (?)-Middle Plio­cene time interval the Elba-Argentario sector was subject to remarkable extensional tectonics, accompanied by important strike-slip components of mostly anti-apennine trend. Analogies with the geodynamic processes that gave rise to the inner belt Neogene basins, lead to inter­pret this sector of the shelf as the penetration path of the Tyrrhenian rifting within the continental area.