Resumen de Migrating submarine furrows on Gabonese margin (West Africa) from Miocene to present: influence of bottom currents?
Laurie Biscara, Thierry Mulder, Eliane Gonthier, Michael Cramer, Jean-Claude Faugeres, Thierry Garlan
Several furrows have been mapped on the slope of the South Gabon continental margin, using acombination of geo-acoustic and core data. The seismic profiles studied display furrows 1-4 km wide and 100-170m deep, that develop normal to the margin between 500 and 1500m water depth. Theses sedimentary structures were initiated above the major Oligocene unconformity and they developed within the Neogene to Present megasequence of progradation of the margin. The furrows show an agradation/progradation pattern, leading tomargin parallel, northwestward migration of their axes through time until Present. A detailed analysis of the internalorganisation of theses structures suggests the action of along-slope bottom current. The evolution of these migrating structures reveals that this northwestward bottom current occurred from the Miocene in the study area, probablyin relation to the formation of the AAIW water.
