The West African orogens (Mauritanides, Bassarides, Rokelides) record a locally complex, polyphase, tectonothermal evolution. The earliest event corresponded to westward rifting of a continental fragment from the West African craton at ca. 700 Ma. This led to development of a rift-facies lithotectonic succession that included sedimentary units and intracontinental igneous sequences. Rifting must have been of limited extent because a western ensialic arc began to develop as early as 680 Ma. The associated convergence culminated in an episode of folding and metamorphism at ca. 650 Ma (Pan-African I orogenesis) in the Mauritanides and Bassarides.

Following widespread deposition of Late Proterozoic...