Fractal analysis of satellite magnetic data for determination of Curie point, geothermal gradient and heat flow in some parts of Bida Basin, Niger State, Nigeria

Abstract

Globally, geothermal energy resources are recognized as one of the environmentally safe and sustainable forms of energy production. The main aim of the study is to evaluate the Curie point depth (CPD) in some parts of the Bida basin. The study area is bounded by longitude 8.0oN to 10.0oN and latitude 4.0oE and 6.8oE.An assessment of Curie-point depth, geothermal gradient, and heat flow has been achieved from the spectral analysis fractal method using satellite magnetic data of the Bida Basin in north-central Nigeria. The acquired satellite magnetic data were divided into twenty-four (24) overlying blocks and each block was analyzed using the spectral analysis technique to acquire depth to the top (Z_t), centroid(Z_o), and bottom(Z_b) of the magnetic source. The depth values were subsequently employed to determine the Curie-point depth (CPD), geothermal gradient, and heat flow in the study area. The result shows that the Curie-point depths (CPD) vary between 8.171 km to 10.635 km with an average value of 9.433417km., the geothermal gradient varies between 55.00759and 70.98274°C∕km with an average of 61.48356°C/km and the heat flow result varies between 136.3423mW∕m² to 177.4569mW∕m² with an average value of 153.7089mW∕m². The plot of the Curie point depth versus heat flow values reveals that the strong relationship between the two is inverse. As a result, the research area's heat flow decreases in correlation with the Curie isotherm depth. Since demagnetized rocks confirm a hot rock quantity in the crust that can be harnessed for geothermal energy exploitation in the basin, these heat flow results indicate that the study area may be a good indicator of geothermal energy potential with minimum CPD, maximum geothermal gradient, and heat flow.