PETROLOGICAL

Five (05) granitic rock samples from Igarra-Ugbogbo area in Akoko-Edo Local Government Area of Southwestern Nigeria were obtained with the aim of determining their geochemical and mineralogical properties using XRF, XRD techniques. Results of the analysis revealed the presence of SiO2 (62.05-79.63wt.%), Al2O3 (10.88-15.10wt.%), Fe2O3(T)* (0.37- 6.29wt.%), K2O (0.89- 8.248wt.%), Na2O (0.17-10.02wt.%) and CaO (0.32-4.68wt.%). The abundance of these major oxides in the samples showed that samples OGB01 and GB05 are felsic magma while UNE02 is probably from a pegmatitic magma and EFU03 and GBO04 are most likely formed from an intermediate magma. Using Al2O3 classification scheme, its showed that OGB01 and UNE02 are peraluminous while EFU03, GBO04, OGB05 are peralkaline. The XRD analysis revealed the presence of quartz, alkali eldspars (microcline, orthoclase and sanidine), plagioclase feldspars (albite and anorthite), muscovite, lime, geothite. The modal composition of the quartz, alkali feldspar, plagioclase were plotted on a QAP diagram which showed that the rock falls within the granite and Quartz-rich granitiod.