Lithological characterization of the lacustrine to deltaic Gombe Formation and continental Kerri – Kerri Formation of the Northern Benue Trough, NE-Nigeria using electrical resistivity method.

Abstract

Geophysical data had been acquired and analysed in the area around Futuk and 
environs, Alkaleri LGA, Bauchi State, Northern Benue Trough, Northeast, Nigeria. 
This was with a view to characterizing the subsurface aquifers of the area. 20 
Vertical Electrical Soundings (VES) were acquired within the study area. The VES 
data were quantitatively interpreted for subsurface sequence delineation and 
aquifer identification. The VES interpretation results revealed three (H, A and K
type), four (KH, KH and QH-type) and five (QHK-type) layers geoelectric models. The 
VES interpretation results delineated five subsurface layers composed of the topsoil, 
clay, clayey sandstone, silty sandstone, sandstone, and quartz sandstone.  Topsoil 
resistivity values ranged between 0.328 Ωm and 12380 Ωm with the thicknesses of 
between 0.75 m and 6.8 m. The clay layer resistivity ranged between 0.03 Ωm and 
9.77 Ωm, with thicknesses of 0.92 m to 7.77 m. The resistivity of the clayey 
sandstone ranged between 10.4 Ωm and 18.1 Ωm, with thicknesses of between 1.64 
m and 15.4 m. The silty sandstone resistivity values ranged between 29 Ωm to 39.3 
Ωm, with thicknesses of 1.36 m to 29 m. The range of resistivity of the sandstone is 
between 41.3 Ωm and 9688 Ωm, with the thickness of between 0.882 m and 12.3 
m. The range of resistivity of the quartz sandstone is from 11356 Ωm to 35370 Ωm, 
with the thickness of 6.88 to infinity. The study concluded that the study area was 
characterized by sandstone, silty sandstone and quartz sandstone aquifers.