Location and Composition
The craton appears to have formed when three Archean cratons fused: Leo-Man-Ghana, Taoudeni and Reguibat. The first two docked around 2,100 Ma (million years ago), and the Reguibat Craton docked with the craton around 2,000 Ma. The roots of the combined craton extend to a depth of over 300 km in the sub-continental lithospheric mantle.
The West African Craton stretches from the Little Atlas mountains of Morocco to the Gulf of Guinea, and is bounded by mobile belts of much younger rocks to the north, east and west. The oldest rocks were metamorphosed 2,900 to 2,500 million years ago. In the Sahara they are mostly covered by more recent sediments from the Phanerozoic Eon. Further south, younger volcanic and sedimentary rocks outcrop in Ghana, Ivory Coast, and Sierra Leone, surrounded by even younger sediments laid down in the Precambrian.
The West African Craton underlies the modern countries of Morocco, Algeria, Mauritania, Senegal, The Gambia, Guinea Bissau, Guinea, Mali, Burkina Faso, Sierra Leone, Liberia, Ivory Coast, Ghana, Togo and Benin.
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