Intertidal Upper Pleistocene algal build-ups (Trottoir) of NW Sardinia (Italy): a tool for past sea level reconstruction

Abstract

Biological sea level indicators such as intertidal coralline red algal build-ups (Lithohyllum rim or Trottoir) are a powerful tool for precise sea level reconstruction.
Several patches of relict intertidal Lithophyllum Trottoir crop out along the north-west Sardinia coasts (Mediterranean Sea, Italy). Based on the strathigraphic correlations and preliminary luminescence ages (avg 120±8 ka) these algal bindstones are associated with the Marine Isotope Stage 5e (MIS 5e, 135-115 ka). A Sedimentological/stratigraphic approach performed on relict Mediterranean Algae Trottoir led us to developed an evolution model and precisely estimate the relative sea level elevation during MIS 5e along the NW coast of Sardinia. Moreover, coastal feature plays a vital role for “Lithophyllum incipient Trottoir” development which under a stable sea condition may growth up to the mature tabular Trottoir aspect. The mean elevation of the studied MIS 5e Lithophyllum bioconstructions is 4.9±0.5 m above the present sea level, which is in good agreement with both the global and the regional data.