Spectral Analysis of High-Resolution Aeromagnetic Data for Geothermal Energy Reconnaissance across Sokoto Basin, Northwest, Nigeria

This study interprets aeromagnetic data across Sokoto Basin with the aim of estimating the Curie point depth, geothermal gradient and heat flow for geothermal energy exploration. The study area lies between the longitude of ۳۰E and ۶۰E and latitudes ۱۱۰N and ۱۳۰N. The total magnetic intensity of the area was subjected to regional/residual separation using polynomial fitting. The residual data was divided into ۳۰ overlapping spectral blocks, where the log of spectral energies was plotted against the frequency; hence, the centroid depth and the top to the magnetic sources were deduced. These depth results were used in estimating the Curie point Depth and geothermal gradient. The total magnetic intensity indicated a variation of ۳۲۹۳۲.۸۴ to ۳۳۱۱۸.۲۷ nT, while the residual map shows magnetic anomalies that vary from -۸۲ to ۵۱ nT, both maps indicated high, low and intermediary magnetic anomalies. The centroid depth results vary from ۴.۶۷ to ۲۸.۸۰ km, and the top to the magnetic source varies from ۱.۰۴ to ۴.۶۵ km with an average depth of ۲.۲۱ km. The Curie point depth range from ۶.۹۲ to ۵۵.۰۴ km with an average depth of ۱۸.۶۵ km, and the geothermal gradients revealed ranges from ۱۰.۵۴ oCkm-۱ at the Southwest (Danko and Gummi) areas to ۸۳.۸۲oCkm-۱ at the northwest (Argungu) area. Therefore, these areas with high geothermal gradients are good indicators of geothermal energy potential and should be exploited for more power generation.

Keywords:

Magnetic anomalies , Spectral analysis , Curie point depth , Geothermal energy , heat flow