Assessment of Geothermal Potential in Sokoto and Environs, North-Western Nigeria, using Airborne Magnetic Data

Abstract

The search for alternative and sustainable energy resources has increased interest in geothermal energy exploration across Nigeria. This study assessed the geothermal potential of Sokoto and its environs, north-western Nigeria, using high-resolution aeromagnetic data. The study area lies between longitudes 4.5°E and 6.0°E and latitudes 12.5°N and 13.5°N within the Sokoto Basin and adjoining basement terrains. The aeromagnetic data were processed and interpreted using spectral depth analysis based on the modified centroid method to estimate the depth to magnetic sources, Curie point depth (CPD), geothermal gradient, and heat-flow distribution. Results show that the depth to the top of magnetic sources ranges from 0.23 to 0.52 km, while centroid depths vary from approximately 3 to 10 km. Curie point depths range from 6 to 19 km, indicating significant variations in the thermal structure of the crust. The derived geothermal gradients vary between 30 and 90 °C/km, whereas heat-flow values range from 75 to 225 mWm⁻². Shallow Curie depths, high geothermal gradients, and elevated heat-flow values are concentrated mainly in the eastern part of the study area, suggesting relatively high subsurface temperatures and favourable geothermal conditions. Comparison with the geological map indicates that these thermal anomalies are largely associated with sedimentary formations comprising shale, claystone, siltstone, and sandstone units. The results reveal considerable geothermal resource potential within the study area, particularly in the eastern sector, and provide a useful basis for future geothermal exploration and development in north-western Nigeria.