Evaluation of Electrical Resistivity Anisotropy in Geological Mapping - A Case Study of Odo Ara, West Central Nigeria.

presence of electrical resistivity anisotropy. The VES curves obtained were predominantly of 3 geoelectric layer of H-type (ρ1>ρ2<ρ3) curves; the topsoil, sandy clay/ clay layer and fractured basement. The pseudo-sections show a good correlation with the geoelectric section. Moreover the iso-resistivity and isopach maps also show a significant correlation with the lithological and strike of the rocks in the area but due to the non uniqueness of electrical resistivity, the lithologic difference between the banded gneiss and the amphibolite at the south western part of the area could not be totally resolved. However, the combination of the anisotropy polygons and the iso-resistivity map has reduced the ambiguity inherent in using a single geophysical parameter.