The relationship between offshore subsidence, continental uplift and sedimentary
deposition to passive margins is poorly understood. A history of dynamic
subsidence, continental uplift and sedimentary deposition to West Africa’s passive
margin was synthesised to produce a framework for predicting patterns of
sedimentary flux to the Mauritanian basin. Stratigraphy was mapped using
seismic/well data and Cretaceous–Recent sedimentary flux was calculated.
Clastic sedimentary flux to the centre of the basin increased significantly during
Neogene times and accelerated across the basin at ~ 5 Ma. The origins of
the Mauritanian basin were explored by backstripping wells from the study
area to calculate subsidence histories. Seismic, well, gravity, magmatic and
tomographic information was used to show that < 0:8 km of rapid Neogene–
Recent subsidence occurred due to the initiation of shallow mantle convection.
Neogene–Recent mantle draw-down caused the creation of accommodation
within the Mauritanian basin that was subsequently filled by clastic sediments
delivered by rivers draining West Africa’s passive margin. The causes of increased
Neogene–Recent sedimentary flux were explored by inverting 14700
African longitudinal river profiles using a calibrated stream–power model to
calculate a history of continental uplift and to predict the pattern of sedimentary
flux to the Mauritanian basin. Results are consistent with independent
stratigraphic observations which indicate that from ~ 30 Ma–Recent, sedimentary
flux to Africa’s major deltas increased and induced a change from
dominantly carbonate to clastic deposition. This pattern of sedimentary flux
is consistent with calculations of offshore sedimentary volumes made using
seismic and well data. I suggest Neogene clastic flux to the Mauritanian margin
was generated by denudation of the uplifting Fouta-Djallon topographic swell
and Mauritinides fold-belt, which appears to have accelerated during the last
~ 5 Ma. Results suggest that mantle-driven convective continental uplift exerts
an important control on the sedimentary budget to Africa’s passive margins.