A 3-D geoelectric model over mineralized zone of Ugonoba, Edo State, Nigeria

Abstract

The occurrence of solid minerals in Ugonoba community was investigated using the 3D electrical resistivity method. Data was acquired using PASI 16GL Terrameter using the wenner electrode configuration with a view to delineating mineral deposits in the study area. During the reconnaissance survey, the outlook of some geological features in the form of outcrops on the surface formed part of the motivation for the geophysical survey within the Ugonoba area. Ten traverses of 200 m maximum spread and 10m electrode spacing with total depth of 40.07 m were obtained in the study area to form a square grid. The acquired data was first processed and inverted using RES2DINV software to generate ten 2-D model images and later collated into 3-D using the inversion code of RES3DINV software which automatically determines a horizontal 3D depth slice, cubes and block models of resistivity distribution. These models generated were interpreted and used to ascertain the true resistivity, lithologic formation, depth extent to any buried mineral and aggregate deposited in the study area. The extracted 3D model images revealed evidence of some geological materials/minerals in the study area which fall within the high resistivity range of 2500 Ωm to 14376 Ωm. It can therefore be inferred from the standard resistivity table that the lithology of study area is composed of non-metallic type of mineral resources which are: clayey sand, lateritic clayey sand, sandstone and limestone. The estimated quantity in metric ton for the dominant lithology (sandstone, granite and limestone) is ± 10% of 1,257,142.9 which can be commercially explored.
 Keywords: Wenner-wenner array, outcrop, minerals, RES3DINV, block models.