Evaluation of geothermal energy potential of parts of the Middle Be-nue trough Nigeria: aeromagnetic and aeroradiometric approach

Geothermal energy potential investigation over parts of Middle Benue Trough, Nigeria, has been evaluated using aeromagnetic and aeroradiometric datasets. The input data consists of nine aeromagnetic and aeroradiometric sheets, respectively. The aeromagnetic data was assembled and digitized; this produces a total magnetic intensity anomalous map (TMI). Similarly, the radiometric data were contoured to produce maps for the three radiometric elements of K, Th, and U. The rose diagram showed that the structural trend in the study area is trending NE-SW and the minor ones are trending E-W and NNE-SSW directions. The radiometric heat model reveals areas of high and low geothermal gradient. The results of quantitative interpretation reveal that the depth to anomalous magnetic sources (the sedimentary infilling) ranges between 0.76 and 4.46 km; while the depth to centroid ranges between 7.29-19.6 km. The Curie point depth (CPD) corresponds to the depth to the bottom of the anomalous magnetic source. The CPD varies from 12.70-37.22 km, the geothermal gradient varies between 15.58-45.670C/km, and the geothermal heat flow varies from 38.9-114.17 mW/m2. The two dimensional structural models show uplifted crust and mantle in some areas due to magmatic intrusions, which gave rise to low CPDs (12 to 28 km), which resulted in high geothermal heat flow values (60 to 115 mW/m2). The geothermal heat flow values around Kwolla, Shendam, Lafia, Akiri, Ibi, and Wukari South fall between 60 and 100 mW/m2, which is the suitable standard for geothermal potentiality.