Petrology and Structural Features of Tsiga and its Environs Northwestern Nigeria

The major rock types mapped in the Tsiga area NW Nigeria, include gneisses and granites associated with minor rocks such as xenoliths and some structural features including foliation, joints, faults and veins (quartz and pegmatite).The mineralogy includes feldspar (orthoclase and plagioclase), quartz, biotite and some accessory minerals. These rock types and the associated structural features have their trends in N-S direction. The structural analysis of joints on the granites of the study area shows that the joints have a trend of NNE-SSW. The joints on the gneisses have a trend of NE-SW. In terms of age relationships of the rocks, gneisses are older than the granites based on deformed features. The gneisses probably originated from sediments, para-gneisses. The granites must have resulted from magma intrusion. The structures in the study area suggests the imprint of the Pan-African Orogeny, as indicated by the structural analysis of fractures. The major rivers in the study area include Yali and Moryaji with their tributaries which formed a dendritic drainage pattern, and are structurally controlled. Surface water occurs during the raining season and underground water are available in the area, occurring in shallow pit dug along the stream and river channels, and the fractured crystalline aquifer. The economic potentials in the area includes; rock aggregates, dimension stone, lateritic soil and alluvium deposits which are used for different purposes and include building houses and construction of roads and bridges and probably rare earth elements at the contact zones between the igneous and metamorphic rocks.