Estimation of Curie point depth and geothermal gradient in parts of the Bida Basin, Nigeria

Abstract

The purpose of this work is to estimate the Curie point depth, heat flow and geothermal gradient from spectral analysis of aeromagnetic data over the Bida and Baro areas, Bida Basin, north central Nigeria. The area covered is approximately 6050 km2 and bounded by latitudes 8° 30′ and 9° 30′ north and longitudes 6° 0′ and 6° 30′ east. The aeromagnetic maps were digitised at an equal interval, and the regional values were removed using polynomial fitting. The resulting residual data were subjected to the upward continuation technique to suppress the short-wavelength components of the residual magnetic anomalies. The upward continuation residual map was divided into eight overlapping blocks, and each block was spectrally analysed. The estimated Curie point depth ranges from 13.6 to 27.2 km, the geothermal gradient ranges from 21.3 to 42.6°C/km with an average value of 34.4°C/km and the corresponding heat flow ranges from 53.2 to 106.6 mW/m2. The average value of the geothermal gradient of 34.4°C/km indicates the possibility of hydrocarbon maturation in the area. Areas of geothermal anomalies with gradients greater than 40°C/km may be prospective for geothermal energy usage in Nigeria for generation of electricity.