DETERMINATION, SANDSTONE DEPOSIT [USING 2- DIMENSIONAL ELECTRICAL RESISTIVITY METHOD], COLLEGE, EDUCATION, ABUDU, ORHIONWON, EDO STATE, NIGERIA

The purpose of this study is to analyze sandstone deposit using 2-Dimensional Electrical resistivity tomography survey investigation of the subsurface and getting detailed structures, properties, deposited volume and it’s economic importance, using the study area as a case study. Two dimensional Electrical Resistivity Tomography (ERT) survey each of 200m in length was laid in College of Education, Abudu, Edo State to locate and delineate sandstone deposits present at igarra. Wenner-alpha array configuration was employed to acquire field data for the various transverses which were generated in parallel and perpendicular directions using dipole-dipole electrode configuration with electrode spacing of 10m. The 2D data were collated and inverted using a computer software known as RES2DINV to obtain true resistivity images of 2D model for each line, which has various options that could be altered to obtain models that correlate with the known geology of the study area. Pasi- Earth Resistivity meter was used to measure the apparent resistivity in order to obtain a 2-D image of the subsurface for each line. These geophysical survey area were observed to be composed of sandstone, clay, limestone, shale, with resistivity values ranging between 259 mΩ to 2160 mΩ for the unit electrode spacing adopted during the period in the survey areas. The data gotten has depth ranging from 2.50m to 40m beneath earth surface and width of 200m. The first transverse has resistivity values between 20 Ωm to 1000 Ωm indicating various subsurface minerals having resistivity within that range, these indicate the presence of sedimentary rocks formation, a large percentage of shale was discovered alongside clay, sandstone and limestone in mall proportions.