Petrochemistry of Granitic Rocks within Muidna and Its Environs Part of Sheet 185 SW, Paiko, North Central Nigeria

The basement rocks within Muidna and its environs part of sheet 185 SW, Paikoarea of North Central Nigeria were evaluated geologically, mineralogically and geochemically using thin section, x-ray diffraction (XRD) and x-ray fluorescence. The aim of this study is to determine their geological associations and petrochemical characterization to aid in the evaluation of their structural signatures, tectonic settings, geochemical trends and their possible mineralization potentials. Geologically, the area under investigation is underlain by granite-gneiss, porphyritic granite, granite, biotite granite gneiss and migmatite gneiss as major rocks and occurrence of quartz veins and quartzofeldspartic veins as minor rocks. The major rock types have suffered several deformational episodes evident from the presence of faults, joints, quartz veins, quartzofeldspatic and pegmatitic veins. Mineralogically, results obtained revealed dormant quartz, orthoclase, and biotite under petrographic microscopic while X-Ray Diffractograph revealed quartz as the dominant mineral followed by albite, orthoclase with minor muscovite. This implies that the rock is felsic in nature and leucogranite/quartz-richgranite to micagranite (muscovite-rich) rock occurrence. Geochemically, data obtained showed presence of high SiO2 content (Av. 38.03wt%), followed by Al2O3 (Av. 8.65wt%) and Fe2O3 content (Av. 2.39wt%). AFM and TiO2 Vs. SiO2 plots reveals a calc- alkaline granitoid, product of S – type magma. SiO2 as an index of differentiation reveal that CaO, MgO, TiO2, Fe2O3, and Al2O3 suggest fractional crystallization as the primary mechanism of differentiation. In conclusion, the study area is underlained predominantly by granitic gneisses, which were emplaced by fractional crystallization with origin linked to sedimentary protolith and have the potential for mineralization.