Évolution volcanologique du mont Manengouba (Ligne du Cameroun) ; nouvelles données pétrographiques, géochimiques et géochronologiques

Abstract

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 stages. The first stage, from 1.55 to 0.7 Ma, corresponds to the building of the Elengoum volcano. The second, between 0.7 and 0.56 Ma, points to the collapse of the Elengoum summit. The third, from 0.56 to 0 Ma, fits with the erection of the Eboga volcano and its caldera sinking, and, from 0.48 Ma, with the adventive fissural activity. The products define an alkaline sodic series, from nepheline-bearing basalts to trachytes. All the lavas evolved by fractional crystallization in a periodically replenished magmatic chamber.