Journal of Earth Sciences and Geotechnical Engineering

Evaluation of Geothermal Energy Potential in Parts of the Lower Benue Trough, Nigeria, Using Aeromagnetic Data

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• Abstract

   

  Nine sheets of Regional Aeromagnetic data of parts of Lower Benue Trough were evaluated through the use of Centroid and forward modelling of the spectral peak methods with a view to delineating structures and basin geometry of the Southern (Lower) Benue Trough of Nigeria. Geological cross sections were used to determine the number of anomalies from the residual magnetic map after which the Discrete Fourier Transform method was applied in calculating and computing the depth to the top (Zt), depth to the bottom (Zo), Curie point depth (CPD), geothermal gradient and heat flow. From the results, the depth to the top of the magnetic source ranges between 0.5km and 12.5km with the highest points towards the south - western part of the study area. The depth to the bottom of magnetic source (centroid depth) ranges from 2km to 54km and the highest areas are located towards the north-eastern part of the study area. The geothermal gradient ranged between 21^oC/Km to 29.5^oC/Km., Ogoja, Oturkpo, and Katsina–Ala are situated within the region of high geothermal gradients (>26.5^oC/Km). The heat flow values range from 22mW/M² to 74 mW/M² and the areas with the high heat flow values are Makurdi, Ogoja, Gboko and Katsina-Ala. The results also show that the Curie temperature isotherm within the study area is not a horizontal level surface, but it is undulating. The study also identified high sedimentary thickness and considerable geothermal potential which could serve as a basis for hydrocarbon accumulation and geothermal exploitation.

   

  Keywords: Geothermal Gradient, heat flow, Crustal Temperature, Geothermal Potentials, Total Magnetic Intensity (TMI).