Sur les modalités de la sédimentation profonde actuelle dans le golfe de Gascogne

Knowledges concerning the nature and distribution of present day sedimentary facies on the slope and in the Biscay abyssal plain are very poor, due to the scarcity of available sea-floor samples.Samples from the uppermost section of Reineck cores obtained in six areas of the Bay of Biscay in water depths ranging from 2,000 to 4,800 m allow us to study the evolution of the sediments according to the water depth and geographic localisation.This study suggests that the sediment from the southern part of the bay independently of depth are characterized by a higher amount in terrigenous components (quartz, clay ...).This disparity is explained by the differing phyisiographic setting (broad shelf in the northern part versus narrow shelf and submarine canyon heading near shore in the south) as well as by a possible influence of the surfacial water masses.It results from this a difference of level of about 2,000 m between the foraminifer lysocline in the northern and southern part of the bay.The determination of the present day CCD in the bay (if present) still awaits further data. [NOT CONTROLLED OCR]