Abstract

A geophysical survey using the vertical electrical sounding (VES) technique was carried out to evaluate kaolin clay mineral deposit of Lakiri village, Obafemi-Owode local government area of Ogun State, Southwestern, Nigeria. Thirty three (33) Schlumberger vertical electrical soundings (VES) were acquired at three different sites. The data obtained was interpreted using WingGLink software to determine the apparent resistivity and thickness of each geoelectric layer. A minimum of three geoelectric layers and a maximum of five geoelectric layers were delineated. The subsurface lithology includes: topsoil, clayey sand/sandy clay, kaolin clay and sandstone. The kaolin clay distribution was identified in about 80% of the VES stations with resistivity values ranging between 1099 - 22037 Ω m and thicknesses between 0.4 - 17 m. Chemical analysis carried out on samples collected from these sites shows that the kaolin clay is acidic and contains high concentration of alkaline metals. The physical analyses revealed the kaolin clay to have an average porosity of 0.46 and bulk density of 1.4 g cm^-3.  The study also revealed that the percentage of clay in the samples collected was found to be higher than that of silt and sand.

 Key words: Kaolin clay, resistivity, bulk density, electrical sounding and geoelectric layers.