The 1800 km divergent continental margin off southwestern Africa lies between two major orthogonal crustal lineaments: the modem Walvis Ridge abutment and the Agulhas Fracture Zone. Secondary lineaments subdivide it into Walvis and Orange sediment basins, and buoyant Lüderitz and Columbine/Agulhas arches. By comparison, the wider conjugate margins of South America suggest that the African side represents the upper-plate fragments of the original, Jurassic South Atlantic rift zone. Oceanic isolation during the early phases of continental separation resulted in a long period (?Hauterivian to late Aptian: 17 Ma) of anoxic marine sedimentation in the palaeo-southeast Atlantic, following the partial infilling of the rift valleys by lavas and continental detritus. Albian to Oligocene sediments accumulated as huge marine delta/fans adjacent to the Orange River and in the bight of the Walvis Ridge. In the former, particularly rapid oceanward progradation during Santonian to Maastrichtian time was facilitated by continuous slumping on a massive scale. During the latter half of the Cenozoic (when terrigenous sediments were replaced by authigenic and biogenic sediments as the dominant forms), the continental margin off southwestern Africa suffered sediment starvation and there was relatively little accumulation on the shelves, and a nett loss from the deep-sea basins because of erosion.