Geology, Petrography, and Structural Analysis of the Basement Complex around Angwan Habu, North-Central Nigeria

Abstract This study investigates the geology and petrography of the area around Angwan Habu, north-central Nigeria, to update existing geological knowledge and evaluate lithological and structural characteristics. The study area is situated within the Nigerian Basement Complex, dominated by Migmatite-Gneiss Complex and Older. The rocks are products of different orogenic episodes. This study is aimed at identifying rock units, mineralogical composition and their structural patterns. These were achieved by geological field mapping techniques and petrographic analysis. Textures, colours, and mineralogy of rocks were observed using hand lens during the geological mapping, structural trend were measured and the resulting data was presented in rose diagrams. Five (5) samples were subjected to thin section and a petrographic transmitted light microscope was used in examining the mineral composition of the sampled rocks. Two lithological units were identified in the area: migmatite gneiss and granitic rocks. The thin section microscopic studies reveal that migmatite gneiss have assemblage of quartz, plagioclase, microcline, biotite and opaque minerals while the granitic rocks have mineral assemblage of quartz, biotite, muscovite, plagioclase and microcline. Structures found associated with the above rocks in the area include veins, joint, xenoliths and faults (dextral). The rose plot of foliations and fractures demonstrate a predominately NE-SW trend, while veins show a NW-SW trend direction which is a clear imprint of Pan-African Orogeny. These structures serve as areas for mineralization. Therefore, further detail geophysical mapping needs to be carried out in order to determine depth to sources of these structures.