The Geology and Petrographic characterization of rocks in part of Tegina Sheet 142SE and Alawa Sheet 143SW North-Central Nigeria

Abstract

The geology of Kawo, Maigro and environs was studied with the aim of characterizing rock types based on their petrography. The area is part of Tegina Sheet 142SE and Alawa Sheet 143SW underlain by rocks belonging to Zungeru-Birnin Gwari Schist Belt of Nigeria and mapped on a scale of 1;50,000. From the geological mapping, four lithological units were observed namely granite, gneiss, schist and amphibolite. These rocks were intruded with quartz at the eastern part which host gold mineralization. Each outcrop location was determined with handheld GPS. Specimen of the rock samples were studies based on their colour, mineralogy and texture. Fifteen (15) out of thirty (30) collected rock samples were selected and sent to petrological laboratory for thin section analysis to determine mineral composition under binocular polarizing microscope with X10 magnification. The result of petrographic analysis showed that gneiss consist of quartz, plagioclase, biotite, hornblende and epidote. Visible grains of biotite, plagioclase elongated prismatic crystal, greenish and pleochroic. Granites consist of quartz, plagioclase and biotite and hornblende. Fracture, foliation, fold, faults, lineation and veins were the observed structures which serves as a zone of mineralization in the eastern corner of the study area.