Central Atlantic margin basins of North West Africa: Geology and hydrocarbon potential (Morocco to Guinea)

This paper summarises the stratigraphy, structure and petroleum geology of the Central Atlantic margin of NW Africa, from Morocco to Guinea. Rifting of the margin began in Late Triassic (Carnian) times and clastic red bed sequences were deposited on both sides of the Atlantic margins. Red beds were followed by early Jurassic evaporite deposition, with three separate salt basins developed. A major magmatic event with dykes, lavas and plutons occurred along the whole Central Atlantic margin at 200 Ma during salt deposition. A carbonate platform developed along the margin in Jurassic to Early Cretaceous times. This consists mainly of carbonate ramp facies, but with rimmed-shelf carbonate platforms developed in Senegal. The deepwater sections of the margin consist of predominantly deep-marine clastic sedimentation from the Jurassic to Recent. Important deltas built out at Tan Tan, Cape Boudjour (Early Cretaceous), Nouakchott (Tertiary) and Casamance (Late Cretaceous). These delta deposits are important for oil exploration, because the rich Cenomanian-Turonian source rock reaches maturity for hydrocarbon generation in these areas.