Geomagnetic and geoelectric investigation of mineral rocks at Awo, Osun state, southwest Nigeria

Abstract

Integrated geophysical survey was carried out at Awo, Egbedore Local Government, Osun State, Southwest Nigeria to identify the location and depth of formation of different magnetic minerals. Proton Precession Magnetometer (G – 856AX) and String R1 resistivity meter were used to obtain magnetic and resistivity data respectively. Sufer10 was used to present magnetic intensity anomaly maps and UBC, MAG3D program (version 4.0) was used to generate 3D inversion of the subsurface magnetic data. The slices of the 3D model at different depths were shown. Partial curve matching and Winresist (version 1.0) were used to treat the apparent resistivity data to generate sounding curves. The apparent resistivities obtained were compared with the published magnetic susceptibilities to identify the magnetic minerals and their locations in the study area. The results of the geophysical methods were in agreement and revealed that rocks at the centre towards the south western region are suspected to be Tantalite and Columbite while the north western region possibly harboured rocks such as Sandstone, Quartz and Calcite. More than fifty percentage of the volume has an intermediate magnetic susceptibility values indicating that the study area is predominantly a pegmatite vein and possibly harbours rocks such as Beryl, Tourmaline and Mica in both disseminated and massive quantities.