ISSN: 2381-8719
Giwa Samuel Chunmada, JM Monde, S Ologun, MS Isa, MI Abubakar
Electrical resistivity investigation was carried out around Adudu and its environ, part of Akiri sheet 232, Middle Benue Trough, Central Nigeria, in order to study the subsurface geologic layer with a view of determining the depth to the aquifer and thickness of the geoeelectric layers. Vertical Electrical Sounding (VES) using Schlumberger array was carried out at seventeen (17) VES stations with the aid of ABEM tetrameter (SAS 300) for data acquisition. The field data obtained have been analysed using computer software (WinResist) which gives an automatic interpretation of the apparent resistivity. The VES results revealed heterogeneous nature of the subsurface geological sequence. The geologic sequence beneath the study area is composed of hard pan top soil (clayey and sandy-lateritic), weathered layer, partly weathered or fractured basement and fresh basement. The resistivity value for the topsoil which have resistivity values varying from 17 Ωm-828 Ωm up to 2 m lateritic with a resistivity value ranging from 80 Ωm-1700 Ωm and 1.4 m to 2.9 m, shaly sand, with resistivity and thickness value varying between 46 Ωm-132 Ωm and 6 m to 19 m, fractured basement with resistivity and thickness values ranging from 161 Ωm-457 Ωm and 4.8 m to 30 m, and finally, fresh basement whose resistivity vary from 600 Ωm-1691 Ωm with an infinite depth. The aquifer resistivity in the study area ranges from 80 Ωm to 457 Ωm with an average value of 120 Ωm.