New insights into the sea-level evolution in Corsica (NW Mediterranean) since the late Neolithic

A new dataset of 16 14C radiocarbon dates better constrains Relative Sea Level (RSL) changes in Corsica Island since the late Neolithic (~3.6kaBCE). Conflicting Holocene RSL histories between the northern and southern portions of Corsica coast are presently available in literature. Here we provide new RSL data obtained by sediment coring and beachrock analysis performed along the eastern coast of the island. These data, coupled with previously available ones, were compared with the predicted RSL variations modelled by means of the sea-level equation solver SELEN. Data from different coastal sectors of Corsica indicate a coherent pattern of RSL since the late Neolithic when the RSL was placed ~ 3.8m below the present mean sea level. Then sea-level rose at rate of ~2mma-1 in the Chalcolithic period (~3.5 and ~2.3kaBCE) followed by a significant deceleration with rates ≤0.4mm-1 from the early Bronze Age to present time (last 4.0ka). The total RSL variation since ~0.5BCE does not exceed ~-0.9m. Our data are in good agreement with previous sea-level estimates made using fixed biological indicators collected in NW Corsica and derived from geo-archaeological investigations in continental France. Conversely, beachrock samples from the Bonifacio strait (southern Corsica) seem to significantly underestimate the RSL position especially between ~3.5 and ~0.5kaBCE. Such discrepancy might reflect radiocarbon calibration issues rather than sea-level variation. These results suggest that further multiproxy investigations are fundamental to better assess the regional sea-level evolution of this archaeologically important sector of the Mediterranean.