The post-rift stratigraphy on the west African margin is characterized by aggradation of a carbonate ramp during Late Cretaceous to Eocene epochs and progradation of a terrigenous wedge from Oligocene to the Present. Such first-order structure has been attributed in the past to geodynamic forcing. However, comparison of the stratigraphic record of the margin with eustasy, δ18O and 87Sr/86Sr curves, shows a close temporal relationship with the Tertiary climate cooling, an increase of continental weathering, and a long-term lowering of sea level. We suggest that the transition from low-amplitude, high-frequency sea-level changes during the greenhouse period to high-amplitude, high-frequency sea-level changes during the icehouse period may account for: (i) the switch from an aggrading carbonate ramp to a prograding clastic wedge, and (ii) the enhanced continental weathering and increased terrigenous influx to the margin.