Taux de sédimentation dans l'étang de Thau à partir des données géochronologiques, géochimiques et des repères stratigraphiques

Geochronological data (Pb-210) Obtained on four sediment cores, coupled with geochemical analysis, X-ray radiography, meteorological data and stratigraphical observations, made it possible to provide a recent and coherent sedimentary history of the Thau basin (Herault, France). Cluster analysis of major elements isolates some horizons presenting a strong terrigenous signature, which are also identified by X-ray. These strata, characterized by high Al, Fe, Ti and K contents, are the consequence of the exceptional flood which occurred in September 1875. This event serves to calibrate the radiochronological data, which are limited at 100 years. Cores located close to the continental and fluviatile inputs accurately record the flood horizon. Measured sedimentation rates range between 0.09 and 0.18 g.cm(-2).yr(-1) and are in general agreement with the knowledge concerning the dynamic of the basin.