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Abstract:
Heat flow investigation of the Gongola sub-basin in northeastern Nigeria has been done from a 2D spectral analysis of recently acquired high-resolution aeromagnetic data as a means to elucidate likely concealed geothermal reservoirs in the basin. The aeromagnetic data, bounded by latitudes 9.0oN and 12.0oN and longitudes 10.0oE and 12.5oE, were divided into 20 overlapping blocks of 180 x 180 km and each block analyzed to estimate the Curie-point depths and ensuing geothermal gradients and heat flow isotherms. The results revealed Curie-point depths ranging from 20.03 to 29.83 km, geothermal gradients ranging from 19.44 to 28.69 oC/Km, and the ensuing heat flow varying between 48.61 and 72.39 mW/m2. The results demonstrate that the study area is dominated by a thick crustal layer (above 15 km) and heat flow that is less than both the global average of 87 mW/m2 and the accepted value of 80 - 100 mW/m2 for anomalous geothermal conditions. Therefore, this study deduces that the area may not have traces of anomalous geothermal settings, having shown no zone of considerable crustal attenuation and elevated heat flow. Even so, the study contributes to the understanding of the thermal state of the lithosphere and regional heat flow variations of the geological formation of the Gongola sub-basin.
