New Insights into the Geomorphological Evolution of the West African Relief

Detailed mapping and prospecting drilling for bauxites in the territory of the Fouta-Djallon Plateau and Mandingo Mountains and the compilation on the succession, lithology, facies, and age of the Mesozoic–Cenozoic deposits of the marginal zone of the Senegal–Guinea Perioceanic Depression have allowed us to correlate and essentially update the scheme of the geomorphologic evolution of the territory of West Africa and to produce the map of planation surfaces. It has been demonstrated for the first time that the base level inverted in the Middle Miocene, and its emergence was responsible for paleogeographic changes and related regional (not local) accumulation of alluvial and lacustrine sediments of the Sangaredi Group, with the subsequent formation of high-grade bauxites with a high content of boehmite. These bauxites were used for the first time as an age indicator in mapping the Middle–Late Miocene stepwise planation surface.