Petrology and Hydrogeochemistry within the Lateritic Profiles Over the Biotite Granites and Pegmatized Granite Schists of Ogbe and Environs, South-South Nigeria

This research work was aimed at studying the petrology of the different rock types and evaluating the quality of groundwater from streams, ponds and bored holes in Ogbe and its environ. Ogbe lies within latitude N 07 19’ 15.00’’ and longitude E 006 05’ 31.5’’ and is part of Igarra schist belt, southwestern Nigeria. The study area forms part of the Mesozoic Older Granite Complex, which intruded the Pre-Cambrian Crystalline Basement. The study area is composed of biotite granite, quartz-biotite granite, granitic schist and pegmatite occurring as dykes. Groundwater samples collected from boreholes and ponds were subjected to physical and chemical analysis. Physical parameters (pH, Ec, TDS and temperature) were measured insitu using standard equipment. Chemical analysis like Anions (NO3-, Cl-) and cations (Mg2+, Ca2+, K+, Na+) were measured in the laboratory using ion chromatography and heavy metals (Cu, Zn, Pb, Mn) were analysed using voltammetric stripping analysis. The mean concentration of the element measured were temp (30.6500˚C), T.D.S (144 ppm), E.C (µs), Ph (7.0250 mg/l), Na (24.7950 mg/l), K (10.3700 mg/l), Ca (23.9400 mg/l), Mg (7.3600 mg/l), Cl (51.7700 mg/l), Fe (.0155 mg/l), Zn (.0050 mg/l), Pb (.0010 mg/l) and Mn (.0010 mg/l) the results were compared with WHO and EPA standards to determine the quality of the groundwater and it was found that the percentage of alkali earth metals and alkali metals were dominant in borehole and pond respectively which was the main source of water in the community.