Evaluation of Curie-point depths, geothermal gradients and near-surface heat flow from high-resolution aeromagnetic (HRAM) data of the entire Sokoto Basin, Nigeria

Abstract

An evaluation of Curie-point depths, geothermal gradients and near-surface heat flow has been carried out from the spectral analysis of the recently acquired high resolution aeromagnetic (HRAM) data of the entire Sokoto Basin in northwestern Nigeria. The HRAM data was divided into twenty two (22) overlapping blocks and each block analyzed using the spectral centroid method to obtain depth to the top, centroid and bottom of magnetic sources. The depth values were subsequently used to evaluate the Curie-point depth (CPD), geothermal gradient and near-surface heat flow in the study area. The result shows that the CPD varies between 11.13 and 27.83km with an average of 18.57km, the geothermal gradient varies between 20.84 and 52.11°C/km with an average of 33.99°C/km, and the resulting heat flow varies between 52.11 and 130.28mWm−2 with an average of 84.97mWm−2. Such heat flow values are suggestive of anomalous geothermal conditions and are recommended for detailed geothermal exploration in the basin.