IJSRP, Volume 5, Issue 6, June 2015 Edition [ISSN 2250-3153]
Dr. M. O. Aku, Mr. L. I. Gani
A geophysical investigation of the subsurface condition of the Permanent Site of Federal University Lokoja, Kogi-state was carried out using electrical resistivity method with the aim of studying the subsurface geologic layers, with a view to determine the aquiferious zones, their depth and the thickness of the geologic layers. Vertical electrical sounding (VES) using Schlumberger array was conducted at twenty (20) VES stations along four profiles with the aid of ABEM SAS 300C terrameter and the field data obtained analyzed using computer software, IPI2win. The VES results revealed the heterogeneous nature of the subsurface geological sequence to contain four layers; topsoil (sandy and clayey laterite), weathered layer, partly weathered or fractured basement and fresh basement with two aquiferous zones (weathered basement and fractured basement). The resistivity value of the topsoil layer varies from 20Ωm to 250Ωm with thickness ranging from 1.0m to 3.0m, the weathered basement has resistivity value ranging from 25Ωm to 300Ωm and thickness between 2.0m to 41.5m, the partial/fractured basement has resistivity value of 100Ωm to 600Ωm with thickness of 5.0m to 50m across most part of the area. Lastly the fresh basement has resistivity of 900Ωm and above with infinite depth. However, the depth from the earth’s surface to the aquiferious zone varies from 10m to 50m and the overburden in the area is low.