Geochemical features and geodynamic significance of the southern Tyrrhenian backarc basin

The southern Tyrrhenian region represents a rare case of an active backarc basin where island-arc basalt (IAB)–type and ocean-island basalt (OIB)–type magmas coexist. IAB-type magmatism is the most common, whereas OIB-type magmas are restricted to a few areas. Geochemical and isotopic characteristics of southern Tyrrhenian submarine volcanic samples are summarized herein, with special attention to samples recovered during recent seafloor sampling. Samples derived from Marsili volcano, the biggest seamount in the Tyrrhenian Sea, together with those of the Prometeo submarine lava field and Palinuro seamount, give a comprehensive picture of the mantle sources of southern Tyrrhenian magmatism. Most of these samples are relatively high-magnesian basalts that approximate primary magma compositions, thus providing insight into petrogenesis of IAB- and OIB-type magmas of this area. Petrological data, integrated with new bathymetric data, allow the geodynamic evolution of the southern Tyrrhenian backarc basin to be reconstructed.