The Djabatoure Basin in Togo (West Africa)

The Djabatoure Massif represents a component of the Pan-African Dahomeyid suture zone in Togo. It is composed of three units that are structured by overlapping contacts. Unit 1 (Djabatoure) is characterized by metagabbroic granulites, amphibolites and pyroxenites; units 2 (Afoulayo) and 3 (Adiaé) are composed of garnet granulites. The objective of this thesis is to characterize these basic massifs from a petrographic and structural study and to trace the different phases of metamorphic recrystallization in relation with the Pan-African deformation. The rocks of these massifs present mainly a Pl-Cpx-Grt-Rt mineralogy, typical of high pressure granulites with locally relics of low pressure Opx-Pl-Ilm granulites. The succession of metamorphic paragenesis shows a probable increase in pressure until the peak of metamorphism in the high-pressure granulite facies followed by retromorphosis in the high-pressure amphibolite facies. Structurally, the massifs and their host rocks are affected by NE-SW oriented fractures.