FIELD AND PETROGRAPHIC EVIDENCES OF GRANITOIDS AND MAFIC MAGMAS INTERACTION IN THE NEOPROTEROZOIC CENTRAL AFRICAN FOLD BELT IN CAMEROON (MAKENENE AREA)

Abstract

Field and petrographic studies of the Makenene area in the Central African Fold Belt in Cameroon reveals several features testifying the mafic and felsic magmas interactions and their coeval nature. They are: (1) the Mafic Magmatic Enclaves (MMEs) scattered throughout the Makenene granitoid pluton and displaying sub-rounded shape and back veining, (2) flow structures consisting of schlierens at the tails of MMEs, folded MMEs along with felsic host granitoids with hinge indicating the flow direction, (3) irregular or cuspate boundary between MMEs and host granitoids, (4) quenching of apatite and biotites minerals, (5) MMEs enclosing other MMEs or felsic host granitoids. The mafic magma injection operated during at least four stages (from early to late crystallization state of the host magma) leading respectively to the formation of homogenized granitoid; sub-spherical MMEs scattered in the pluton; dismembered dyke and undisturbed synplutonic mafic dyke. The Makenene area registered four deformation phases (D1 to D4). The first two deformation phases occurred before the magmatism and migmatization events. The third phase is coeval to the magmatism and the migmatization period (at the Eburnean orogeny (2.08-2.07 Ga)). The fourth phase is related to the Panafrican orogeny.