Full Length Research Paper
Abstract
Aeromagnetic data over part of the Abakaliki Lower Benue Trough has been evaluated to estimate the geothermal energy potential and model the morphology of the basin through assessing the depth to the magnetic basement and modeling prominent magnetic anomalous bodies. The data were acquired, analyzed, and interpreted. Qualitative analysis, using visual inspection of Total Magnetic Intensity (TMI), Residual Anomalous (RAM), and Analytical Structural (ASM) maps, shows that the majority of faults trend east-west, while few others orientate in the NNE to SSW directions. The visual assessment of TMI and RAM maps reveals high magnetic intensities ranging from 6700 to 7505 nT and -100 to 250 nT, respectively. Areas with high magnetic values suggest lower sedimentary infilling, while areas with lower magnetic values suggest thicker sedimentary covers. The western part of the research area exhibits structural alteration around the Ishiagu, Enyigba, and Eziagu regions. There is evidence of intrusive bodies around Obubura and Onyen in the southeast region of the research area. The quantitative results show two depth sources: the deep sources range from 10.71 to 21.88 km, and the shallow sources range from 2.52 to 9.45 km. The deeper sources suggest further depth to the geothermal contact sources. The sediment accumulation pattern from the basin morphological map reveals uneven, undulating, and structurally controlled depositional patterns across the entire research area. The results also show a linear depression with sedimentary accumulation trending northwest-southeast. The 3D subsurface basal configuration map reveals uplifting and depression, which is a distinctive expression of folds. The average sedimentary infilling thickness and the geothermal gradient are 8.2 km and 13.9°C/km, respectively. The correlation between heat flow and geothermal gradient shows linear relationships, implying that areas of higher heat flow correspond to regions of higher geothermal energy.
Key words: Fourier transform, sedimentary infilling, depth modeling, basin morphology, geothermal energy.
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