Investigation of the Depth to Basement and Basement Topography at Narayi Area of Kaduna State

Abstract

The interpretation of 15 Schlumberger Vertical Sounding (VES) data
along 3 profiles were carried out in Government Day Secondary School
Narayi, Kaduna State. This is an attempt to investigate the Depth to
Basement and the Basement topography of the area. The Ohmega
Terrameter was the principal instrument used. No booster was used. The
Schlumberger electrode configuration was used in the data acquisition.
The method consists of expanding AB (distance between the current
electrodes) while MN (distance between the potential electrodes) is kept
fixed. The VES curves were interpreted using IPI2Win resistivity
computer software. The survey area is dominated by mainly four layers
(topsoil, weathered basement, fractured basement and fresh basement).
The results of the interpreted VES data showed an uneven distribution of
the basement layer, with resistivity values ranging from 4.75Ωm -
220000Ωm. The basement layer is predominantly fresh granitic rocks.
The depth to basement ranges from 10.8m – 21.96m with an average
depth of 15.42m. Clay constituents are needed to be excavated at an
average depth of 6m from the topsoil before laying any foundation.