Basin development on the Atlantic margin of Africa, according to seismic evidence, began with rifting, in an alluvial and lacustrine environment, followed by regional subsidence and later marine conditions. Evaporites commonly were deposited during the transition from rifting to subsidence. Regional subsidence probably began after separation of continental blocks. Oceanic fracture zones and related tectonic trends onshore allow for a subdivision of the African Atlantic marginal belt into four segments: Northwest Africa, Equatorial, Cameroon-Gabon-Angola, and Walvis Ridge–Cape. Each segment has its own basin history.