Abstract

Liman Katagum and Bagel are part of the Eastern margin of the Northern Basement Complex rocks of Bauchi Nigeria. The rocks are well exposed within the river channel in the western part of the study area, towards the east are few outcrops trending in NE-SW direction. The main aim of this research is to classify the rocks using morphological petrology and geochemical parameters. Three distinct migmatites were identified; Banded orthogniesses which are foliated coarse grained to porphyritic in texture with alternating bands of felcic rich quartzo-feldspathic and dark biotite rich bands, chemically the orthogneisses are tholeiitic with some slightly calc-alkaline showing enrichment of iron, and also calic to calc-alkaline. They also exhibit peraluminous character indicating source from S-type granitoids. The Diatexite migmatites are weakly foliated, and have granular texture, they are dominantly metaluminous to peraluminous showing mix source between I and S type granitiods, most of them are calc-alkaline showing enrichment of alumina. The anatectic granite are similar to the diatexites, only that they are more leucocratic, have more silica and k-feldspar with lesser biotite and other mafic minerals. The presence of biotite and amphibole within the banded orthogneisses is an indication that the rocks are within amphibolite facie metamorphism while the appearance of orthopyroxene within the diatexite migmatite indicates that the grade of metamorphism has increased to granulite facie metamorphism towards the eastern part of the study area.

Key words: Banded orthogneisses, Diatexite migmatite,Liman Katagum, Amphibolite, Granulite Facie, Anatectic granite