Despite the fact that lots of works were done on the Pre-Cambrian rocks of eastern Nigeria, classifying the rocks especially the charnockites is still controversial. Some petrologist believed that the charnockites are metamorphic rocks simply because they occur within orogenic belts and have few metamorphic signatures and mineral assemblages, while other believed they are just igneous intrusions within the metamorphic rocks that intruded during the Pan African orogeny. The migmatites and gneisses also needs further examination, so as to know if they are banded orthogniesses, stromatolitic, schlieren, or nebulitic migmatites, the grade of metamorphism is also need in order to know if the rocks were metamorphosed on granulite or amphibolite facie metamorphism. The economic potential of this rocks needs to be assessed in order make a good recommendation to investors.
Key words: Charnockites, migmatites, Nigeria, granulite.
|
