MORPHODYNAMICS AND SEDIMENTARY EVOLUTION OF ROCKY PLATFORMS IN FRONT OF THE CLIFFS OF ESTREMADURA (PORTUGAL) - (OBSERVATIONS OF MOBILE SUBMARINE SANDS)

Morphodynamics and sedimentary evolution of rocky platforms in front o f the cliffs of Estremadura (Portugal) (observations of mobile sumbari ne sands). - The rocky platform at the base of cliffs in Estremadura ( Portugal) is an area of active sediment transport. Sands are moved sho reward along structural depressions (submarine channels) in the platfo rm. Terrigenous products also arrive there from cliffs and slopes, esp ecially where they are exposed to waves. These transits have links wit h plant and algual covers. A cross section from the top of the slope, to the rocka platform (through beach, submarine beach and submarine ch annel in the platform) is presented. Grain size analysis and morphosco py give a clue for the understanting of dynamics. A theoretical approa ch is then conducted, using mainly sand deposition models developed by Electricite De France. The sedimentary dynamics are mainly dependent on the tidal sea level fluctuation.