Late Quaternary sea-level changes along the Tyrrhenian coast near Orbetello (Tuscany, central Italy): palaeoenvironmental reconstruction using ostracods

Abstract

A multidisciplinary study has been carried out on a 51 m long core, drilled on coastal lowlands near the Albegna River (Tuscany, Central Italy). Both sedimentological and faunal analyses (ostracods and molluscs) indicate a coastal lagoon environment repeatedly influenced both by the rising Holocene sea and the Albegna River alluvial inflow. δ 13C, δ 18O, Mg/Ca, Sr/Ca and 87Sr/ 86Sr analyses were performed on Cyprideis torosa shells in order to detail the influence of Albegna River freshwater on the coastal lagoon water. The analytical data illustrate the difficulties of using geochemical proxies in marginal marine settings. Four radiocarbon dates provide a chronostratigraphy for the early Holocene part of the core. The data are used to reconstruct Late Pleistocene to early Holocene palaeoenvironments along this part of the coast and show the development of freshwater environments followed by a coastal brackish lagoon formed in response to the initial Holocene rapid rise in relative sea level. An attempt is made to relate sediments and age data from the core to the relative sea-level curve for the Tyrrhenian Sea.