Lithological Identification Using Electrical Resistivity Tomography: Case Study of Unguwan Dikko, Kalgo Local Government, Northwest Nigeria

Abstract Lithological identification was conducted in Unguwan Dikko of Kalgo Local government, Kebbi state. Using electrical resistivity tomography (ERT), nine profile lines were created throughout the research region. The area is situated between the longitudes 12° 16ʹ 0ʺN and latitudes 4° 20ʹ 0ʺE. This study is aimed at providing detailed and accurate Imaging of subsurface lithological units within Unguwan Dikko. The ABEM SAS 300C terrameter instrument was used to carry out the survey. The field data obtained were analyse using RES2D software. The result delineated top soil with resistivity varying from 1250Ωm to 5248Ωm and a depth of 0-3m. The intermediate clay with lower resistivity values varying from 387Ωm to 1772Ωm and a depth of 3-15m. The deeper sandstone layer with higher resistivity values varying from 1136Ωm to 6964Ωm and depth of 15-25m, reflecting their distinct geological properties. The variations in thickness and depth of these layers across profiles highlight the complexity of the subsurface composition within the area of study. To maximize its potential, it is recommended that studies integrate ERT data with borehole logging and other geophysical methods for improved accuracy. Keywords: Electrical, Layer, Lithology, Resistivity, Subsurface, Tomography