Mesozoic Source-to-Sink of the African margin of the Equatorial Atlantic

International audienceThe objective of the Transform Source to Sink Project (TS2P) is to link the dynamics of the erosion of theWest African Craton to the offshore sedimentary basins of the African margin of the Equatorial Atlantic atgeological time scales. This margin, alternating transform and oblique segments from Guinea to Nigeria, showsa strong structural variability in the margin width, continental geology and relief, drainage networks and subsidence/accumulation patterns. We analyzed this system combining onshore geology and geomorphology as well asoffshore sub-surface data.We produced paleogeographic maps at the scale of West Africa spanning the continental domain and offshorebasins since 200 Ma. Mapping spatial and temporal distribution of domains either in erosion (sources) or inaccumulation (sinks) document the impact of the successive rifting of Central and Equatorial Atlantic on thephysiography of the area. We use low temperature thermochronology dating along three transects perpendicular tothe margin (Guinea, Ivory Coast and Benin) to determine periods and domains of denudation in that framework.We compare these data to the Mesozoic accumulation histories in passive margin basins and discuss theirstratigraphic expression according to the type of margin segment they are preserved in. Syn-rift architectures(Early Cretaceous) are largely impacted by transform faults that define sub-basins with contrasted width of crustalnecking zone (narrower in transform segments than in oblique/normal segments). During the Late Cretaceouspost-rift, sedimentary wedges record a transgression along the all margin. Proximal parts of the sedimentarywedge are preserved in basins developing on segments with wide crustal necking zone while they were erodedaway in basins developing on narrow segments. As a difference, the Cenozoic wedge is everywhere preservedacross the whole width of the margin