Cretaceous – Cenozoic Magmatism and Volcanism
Basaltic lava plateaus, trachyte plugs and domes, large central volcanoes and small basalt cinder cones with thin flows are all found among the more southerly manifestations of Cenozoic volcanism in West Africa (Wright, 1985). This province also includes the remarkable offshore continuation of the Cameroon volcanic line, the four islands situated in the Gulf of Guinea itself. Areas of basement doming include the Jos Plateau, southeast of the Benue Trough, with probably still greater uplifts; and the Adamawa Highlands further east, where lavas of the Ngaoundere Plateau overlie the Ngaoundere fault zone, which was reactivated in the Cretaceous. The flood basalts of the Biu Plateau are situated on the Zambuk Ridge of the Upper Benue Trough, and the smaller Longuda Plateau lies near the bifurcation of the Upper Benue Trough, which has been identified as a possible secondary triple junction (Fig. 3.1).