Estimates of Curie point depth, geothermal gradient and near-surface heat flow of Bida and environs, Nupe Basin, Nigeria, from high-resolution aeromagnetic data

Abstract

The Nupe Basin is a northwest–southeast (NW–SE) trending intracratonic sedimentary basin in the central part of Nigeria with its coordinates defined by longitude 5°00′ to 8°00′ E and latitude 7° 00′ to 11° 00′ N. Spectral inversion of the high-resolution aeromagnetic data was carried out to estimate the Curie point depth (CPD), geothermal gradient and heat flow regime of parts of the Nupe Basin, Nigeria. The estimate of regional temperature distribution and the identification of thermally active regions within the study area were made from the spectral analysis of high-resolution aeromagnetic data which were divided into 16 overlapping spectral blocks to obtain the top and centroid depths of the magnetic sources which were later used to calculate the heat flow characteristics. The estimated Curie point depths range from 21.43–26.71 km with an average CPD value of 24.54 km, while the geothermal gradient ranges between 21.72 °C km−1 and 27.07 °C km−1 with an average value of 24.39 °C km−1. Similarly, the estimated heat flow regime of the study area ranges from 54.30 m Wm−2 to 67.67 m Wm−2 with an average value of 59.41 m Wm−2. The range of estimated geothermal parameters in the study area is an indication that the area is not a volcanic or thermally active region and therefore has little potentials for geothermal energy exploitation. The geothermal play of the area, therefore, was revealed to be of the conduction-dominated play type, typically a combination of the basement and intracratonic basin geothermal play types.