The Correlation of Geothermal Energy Potential Deduced from Aeromagnetic and Aeroradiometric Data of Akiri and Environs, North-Central Nigeria

Abstract

The aeromagnetic and aeroradiometric data were combined to investigate the geothermal energy potential of Akiri and Environs, North-Central Nigeria. The aeromagnetic and aeroradiometric data were obtained from the Nigerian Geological Survey Agency (NGSA), Abuja. The data consists of nine square map sheets of Wamba, Kwolla, Shendam, Lafia, Akiri, Ibi, Makurdi, Akwana and Wukari. The LANDSAT imagery data of the study area was obtained from the National Centre for Remote Sensing, Jos. The spectral analysis method was applied to aeromagnetic data to obtain the geothermal parameters of the magnetic sources. The results show that the depth-to-top of magnetic sources in the study area ranges between 0.76 and 4.46 km; while the depth-to-centroid ranges between 7.29 and 19.6 km. The depth-to-bottom of magnetic sources corresponds to the Curie point depth (CPD) in the study area which is the depth at which magnetic rocks lose their magnetism. The results show that the CPD varies between 12.70 and 37.22 km, the geothermal gradient varies between 15.58 and 45.67 ^◦C/km, and the geothermal heat flow varies between 38.9 and 114.17 mW/m². Two dimensional structural models were constructed to show the estimated depths at each profile taken. The 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 to high geothermal heat flow values (60 to 115 mW/m²). The results show that there are low values of CPD in some areas which indicates that the study area has geothermal energy potential. The study shows that the geothermal energy potential deduced from aeromagnetic data correlates well with the geothermal energy potential deduced from aeroradiometric data.