Geology and Petrography of Basement Rocks around Tsauni, Northwestern Nigeria

Abstract

This work studied the geology and petrography of basement rocks around Tsauni and its environs with the main aim of establishing the different rock types present macroscopically and microscopically. The study area is part of sheet 54 Gusau NW, Northwestern Nigeria defined by latitude 12˚12'00”N and 12˚9'00”N and longitude 6˚43'30”E and 6˚40'30”E. To achieve the aim, geological mapping was conducted in which fresh rock samples were collected and structures were studied and measured. The samples were subjected to petrographic analyses and their microscopic features were observed under the microscope. On the field, one major rock is encountered, granites (fine-medium grained and medium-coarse grained granites) while two minor rocks;
quartz and xenoliths are mapped with the former being younger and the latter older than the granites. All the analyzed rocks are seen to contain quartz (40%), orthoclase feldspar (40-50%) and biotite (10-20%). They are therefore said to be granites of the Older Granites of northwestern Nigeria believed to be of late Cambrian to lower Paleozoic in age. Strike-slip faults and joints were found as the structures associated with the rocks. Economically, these rocks can be best used in engineering constructions. There exist meandering rivers in the area enriching the inhabitants with surface water and presence of hand dug wells pinpointing the availability of groundwater. However, geophysical survey is recommended to back this up.