Evidence of former Holocene sea level in the Marennes-Oléron Bay (French Atlantic coast)

Both sedimentological and mollusc death assemblage analyses from a 14C-dated core, coupled with seismic stratigraphical analysis within the Marennes-Oléron Bay (French Atlantic coast), provide a detailed record of environmental changes during the end of the Holocene rapid sea-level rise. Lithofacies and mollusc fauna changes evidence the transition from a former intertidal bare mudflat to a subtidal environment. The newly shown former sea-level record, computed from radiocarbon-dated Scrobicularia plana shell, matches previously published local sea-level curves. This drowned mudflat belongs to an incised valley-fill that provides new insights into valley-fill successions along the French Atlantic coast.