GEOELECTRICAL INVESTIGATION OF THE SUBSURFACE LITHOLOGY AT THE PROPOSED INTERNATIONAL STADIUM, MINNA, NIGER STATE, NIGERIA

Abstract

Geoelectrical investigation was carried out to evaluate the viability and to determine the subsurface Lithology, depth to bedrocks as well as to establish prolific aquifers at the proposed Minna International Stadium, Niger State, Nigeria. The area is located at the Basement Complex of Nigeria which comprises of: Migmatites-Gneiss Complex, the Schist Belt, the older granites and undeformed acidic/basic dykes. Vertical electrical sounding (VES) surveys were conducted using a resistivity meter along six (6) profiles, at 50 m interval from each sounding point; and a total of 36 VES measurement were made. The results of the VES suggests that the entire subsurface of the proposed stadium, is made up of three (3) distinctive Lithologies; the First layer is Top Soil/Lateritic Particles with resistivity value between 20.38 and 272.8 Ω𝑚 it thickness is between 0.09 m to 5.84 m, the Second layer is a weathered/fractured basement with resistivity values variation between 45.15 and 1017 Ω𝑚, its thicknesses ranges between 2.54 m and 24.9 m and the Third layer is fresh basement with resistivity values from 1259 to 3606 Ω𝑚. The result of this work shows that the second layer is generally weathered Basement, it is therefore advisable for engineers to consider this in their design. The foundations should be situated towards the southeastern, southwestern and northern section of the site, where the bedrocks are shallow, uplifted and consolidated. The site is suitable and viable for the construction of the proposed stadium; the depth to bedrocks is more than 2.54 m from the surface. Borehole should be drilled on the following VES points; A6, B3, B4, C6, C1, C2, D1, D3, E2, E3, F2 and F1, these VES points depicts zones of good fractures