Determination of the Heat Flow in the Sokoto Basin, Nigeria using Spectral Analysis of Aeromagnetic Data

Abstract

In this study, the Determination of heat flow in the Sokoto Basin North Western Nigeria using spectral analysis of aeromagnetic data was carried out. The study area is bounded by latitude 11.0^oN to 13.5^o N and longitude 3.5^oE to 6.5^oThis research is necessitated by the need for renewable alternative sources of energy for use in Nigeria. Depth estimates were made from the spectral analysis of the magnetic anomalies. The Upward continuation filter control was utilized to suppress the short wavelength components in the Sokoto Basin. The continuation was carried out at various heights (2km, 5km, 10km, 15km and 20km). The centriod depth which relates to the point where magnetism is lost in the crust was calculated using the rate of decay of the spectrum. The results from spectral analysis suggested that in the Sokoto basin the basement is deepest at the north eastern portion toward Niger Republic and varies between 0.61 and 1.54km, while the centriod depth varies from 6.35 to 13.05km. It also suggested that basin is underlain by a Curie-point isotherm of between 11.36 to 22.30km and corresponding gradient and heat flow values varying from 26.18 to 44.62⁰ C/km and 52.36 to 98.57mW/m² respectively. The maximum heat flow is found around the central area (i.e around Tambuwal). The average heat flow in normal continental region is about 60mW/m² , values between 80 and 100 mW/m² are good geothermal sources while values greater than hundred is an indication of anomalous condition. Anomalous and good high heat flow for good geothermal sources was observed in the area. These areas with high heat values may be good geothermal sources and therefore are recommended for further investigation.

Keywords: Aeromagnetic, spectral energy, geothermal gradient, Curie point, sedimentary