Geometry of the African margins of the Equatorial Atlantic

Delphine Rouby (1) , Jing Ye (1) , Dominique Chardon (1) , Damien Huyghe (1) , François Guillocheau (2) , Cécile Robin (2) , Massimo Dall’asta (3)

1 GET - Géosciences Environnement Toulouse
2 GR - Géosciences Rennes
3 TOTAL PAU

The 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 at geological time scales. This margin, alternating transform and oblique segments from Guinea to Nigeria, shows a 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 as offshore sub-surface data. Syn-rift architectures (Early Cretaceous) are largely impacted by transform faults that define sub-basins with contrasted width of crustal necking zone (narrower in transform segments than in oblique/normal segments). During the Late Cretaceous post-rift, sedimentary wedges record a transgression along the all margin. Proximal parts of the sedimentary wedge are preserved in basins developing on segments with wide crustal necking zone while they were eroded away in basins developing on narrow segments. As a difference, the Cenozoic wedge is everywhere preserved across the whole width of the margin.

Domaines: Stratigraphie

Delphine Rouby, Jing Ye, Dominique Chardon, Damien Huyghe, François Guillocheau, et al.. Geometry of the African margins of the Equatorial Atlantic. 25 ème Réunion des sciences de la Terre (RST 2016), Société Géologique de France, Oct 2016, Caen, France. pp.281. ⟨insu-01388687⟩