Depth estimation for geothermal reconnaissance deduced from aeromagnetic data over the Mambilla plateau and environs, Taraba State, Northeastern Nigeria

Abstract

The geothermal gradient, heat flow and Curie point depth (CPD) were calculated using aeromagnetic data to assess their viability in terms of energy generation around Mambilla plateau and environ, Northeast, Nigeria. Each block of spectral plot was used to determine the depths to the top boundary (Zt), to bottom (Zb) and centroid (Zo). Empirical formula was used to calculate the geothermal gradient, Curie Point Depth (CPD) and heat flow in the area. The resulting depth measurements were then consider as the area's geothermal gradient, heat flow, and curie point depths (CPD). Two CPD locations with geothermal potential are described in the results: areas with shallow curie point depths (0.11-1.72 km) and areas with deeper curie point depths (0.34-4.46 km). The geothermal gradients measured range from 46.22 to 121.620oCkm-1, while the measured heat-flow values range from 139.16 to 304.05 mWm-2 . This study also reveals how complex magmatic and tectonic linkages of large intrusions and fault systems, particularly the Chain faults that may have extended into the study area, are related to geothermal systems. A common CPD of 3oC100m-1 or 30oCKm-1 and average thermal conductivity values ranging from 105.68 to 227.63mWm-2 are considered to have a good potential for geothermal energy. This result have strong and positive correlation with what is obtained in some countries were geothermal energy is been utilized for power generation. The potential for geothermal energy resources in the area is therefore very high. The study's most important and practical finding is that the area has good potentials for geothermal energy resources, which could be used to compliment the Government-owned Mambilla Hydro-Electric Power Plant, as a reliable renewable energy source.