Basin-scale geothermal–structural mapping of the Nigerian Benue Trough using aeromagnetic, satellite gravity, and aeroradiometric data

Abstract

• Integrated geophysical data reveal basement structures and geothermal anomalies. • NE–SW rift corridors align with warm springs and heat-producing zones. • Felsic intrusions and gneissic uplifts mark zones of high radiogenic heat (RHP >3.0 µW/m³). • 2-D gravity models show thick sediments and major basin-bounding faults. • A novel structural-geochemical model guides sustainable geothermal exploration. The Middle–Upper Benue Trough (MBT–UBT) of Nigeria contains warm springs and felsic intrusions that indicate substantial geothermal potential, yet basin-scale geothermal–structural controls remain poorly constrained. This study integrates magnetic, gravity, and radiometric datasets—previously analysed separately in other studies—into a joint interpretive framework that images intrusive and basement highs, asymmetric sedimentary depocentres, and steep fault-controlled gradient belts, while radiogenic heat production (RHP) delineates radiogenic crustal domains, resolving the coupled heat-source–reservoir–pathway system. The resulting geothermal–structural framework identifies two corridor-scale geothermal targets (Awe–Keana–Akiri–Azara–Ribi and Wase–Kurmi–Pinau) and three first-order tectono-geophysical domains that control geothermal heat and fluid favourability: (i) intrusive and uplifted basement highs expressed as co-located magnetic–gravity highs, (ii) deep sedimentary depocentres locally exceeding 6–6.5 km defined by Bouguer gravity lows and 2-D gravity-depth modelling, and (iii) steep gradient belts interpreted as high-permeability fault corridors. Two continuous radiogenic belts—Keana–Awe–Azara–Akiri–Ribi (>3.0 µW m⁻³) and Wase–Kurmi–Pinau (∼2.3–2.9 µW m⁻³)—align with NE–SW rift-parallel structures segmented by NW–SE to E–W transfer zones. The strongest convergence of intrusive highs, elevated RHP, deep depocentres, and steep structural gradients occurs along the Awe–Keana–Akiri–Azara–Ribi corridor, with Wase–Kurmi–Pinau emerging as a secondary target. These findings establish the MBT–UBT as a structurally governed and radiogenically enhanced geothermal province and provide a transferable framework for geothermal prospect ranking and future drilling in intracontinental rift systems.