ORIGIN, SEDIMENTARY PROCESSES AND DEPOSITIONAL EVOLUTION OF THE AGADIR TURBIDITE SYSTEM, CENTRAL EASTERN ATLANTIC

The Oligocene to Recent Agadir turbidite system occurs in the Agadir B asin, abutting against the continental margin off South Morocco (centr al eastern Atlantic). This system is part of the submarine drainage sy stem linking back to the Anti- and High Atlas mountains through the Ag adir Canyon, and its sedimentary evolution is shown to comprise latera l shifts of canyon, channel, overbank and lobe deposits, governed by l ocal topography (draped palaeorelief seamounts, and a contourite ridge ) and channel avulsions. In addition, the turbidite system shows an ov erall retrogradational stacking (migrating about 60 km upslope). This probably reflects a decrease in gradient on the continental margin, gr adual basin filling, and/or a progressive decrease in energy and load of the sediment gravity Bows that fed the system. The latter change in sediment flux could result from the interplay between the progressive denudation of the source areas, together with the climatic change whi ch led to the present arid/desertic conditions in the hinterland. The seismic features observed with new ultra-high resolution seismic tools allow the recognition of the present-day sedimentary activity within the Agadir turbidite system, and this is related, among other factors, to the active seismicity of the area.