Preliminary Studies of the Litho-Structural Evolution of areas around Obudu Northeast, Sheet 291, Southeastern Nigeria.

Abstract

Rocks underlying the northeastern sector of Obudu area forms part of the Bamenda massif which is a westward extension of the Precambrian terrains of Cameroon into southeastern Nigeria. These rocks are frequently found in the basement complex of Nigeria and include the migmatitic gneiss as the early metamorphic tectonites constituting over 60% of the outcropping rocks in the study area. The basement rock of the study area comprised of the migmatite gneiss and biotite-hornblende garnetiferous gneiss as well as the porphyroblastic gneiss and granite gneiss which formed the basement intruded by the Older granites (Pan-African granitoids). The Older granites in this area include charnockite, porphyritic granite, medium grained granite, diorite and pegmatite/aplite with relatively undeformed veins of dolerite and quartz. The presence of garnet nodules in the biotite-hornblende gneiss indicates high grade tectono-thermal metamorphism of a possible sedimentary protholith. The shearing observed in some rock outcrops are indication that there have been a series of structural deformation alongside magmatism and metamorphism in the area.