This paper reports the geology and mineralogy of the clay occurrences around

ABSTRACT:This study was carried out in Sapele, Jesse and Oghara, Delta state to determine the groundwater potential by correlating results of seismic refraction survey and those of electrical resistivity studies. Fifteen vertical electrical sounding (VES) locations were sounded and nine seismic stations were shot to complement the study. The seismic results show that the area has generally three or four layer formations. The thin weathering layer with thickness of 1.0 -3.5 m has velocity range of 250 -350 m/s. while the velocities of second and third layers range from 900 -1400m/s to consolidated zone. The analysis of the VES data delineated 4 to 5 layers with HK and AKA curves types mainly and showed that the formation of the area is basically conducting which suggests the existence of heavy clay or clayey sand formations. Although the numbers of layers delineated differ, both methods indicate that viable aquifer at Sapele and Jesse is generally within 25m although false and contaminated aquifer may be intercepted at 10 -15 m. On the contrary, Oghara is more of sandy formation with aquifer above 35 m. @JASEM

Studies were carried out on the geochemistry of 18 representative samples of the granite gneiss host rock, common Pb dates on six granite gneiss whole rock samples, six feldspar sample separates, and six samples from the lode gold deposit in the Ilesha schist belt. The AFM plot for the biotite granite gneiss indicated that its protolith was derived from a subduction related tectonic setting. The granite gneiss had low U/Pb and Th/Pb ratios (0.10 to 0.31 and 0.33 to 1.31, respectively), and upper crustal Pb content of 30-47 ppm. The 207 Pb/ 204 Pb, 206 Pb/ 204 Pb, 208 Pb/ 204 Pb, were extremely homogeneous in the host rock, the feldspar, and the pyrite indicating derivation from a subduction related environment like a back arc or island arc. The two-stage Stacy and Kramers (1975) Pb-Pb model dating method of interpretation adopted in this study indicated that the granite gneiss was emplaced at 2750 ± 25 Ma in an orogen. On analysis, common Pb in pyrite yielded an average model age of 550 Ma. This Pb systematics indicated that Au was derived from the volcanics in the Ilesha schist belt by hydrothermal leaching, transported through the same medium and deposited in the massive quartz veins as thio-complexes from which native gold was liberated through interaction of the ore fluid and spinnels in the host rock.