Geometry of the African margins of the Equatorial Atlantic
Résumé
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.