The Senegal sedimentary basin, also known as the Senegal-Mauritania Basin, formed as the largest marginal basin in Africa during the rifting apart of the center of the supercontinent Pangaea to form the Atlantic Ocean in the Mesozoic. The basin is 1400 kilometers from north to south and 500 kilometers at its maximum width at Dakar. This Atlantic-type half-basin has gently dipping sedimentary units that get thicker closer to the coast.