Volcanological evolution of the mount Manengouba (Cameroon line), new petrographical, geochemical, and geochronological data

The mount Manengouba is a polygenic volcanic complex of the Cameroon line, which was built in the Quaternary, between 1.55 and 0 Ma, during three stag es. The first stage, from 1.55 to 0.7 Ma, corresponds to the building of th e Elengoum volcano. The second, between 0.7 and 0.56 Ma, points to the coll apse of the Elengoum summit. The third, from 0.56 to 0 Ma, fits with the er ection of the Eboga volcano and its caldera sinking, and, from 0.48 Ma, wit h the adventive fissural activity. The products define an alkaline sodic se ries, from nepheline-bearing basalts to trachytes. All the lavas evolved by fractional crystallization in a periodically replenished magmatic chamber. (C) 2001 Academie des sciences / Editions scientifiques et medicales Elsev ier SAS.