Journal de géologie et géophysique
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Integration of Aeromagnetic Interpretation and Induced Polarization Methods in Delineating Mineral Deposits and Basement Configuration within Southern Bida Basin, North-West Nigeria

Ayatu Ojonugwa U, Chukwudi Ezeh C and Augustine Chinwuko I

Aeromagnetic data interpretation and Induce Polarization (IP) method has been integrated and interpreted with a view of delineating magnetic minerals within some part of the Southern Bida Basin, Nigeria. Spectral analysis method was used in delineating the depth to magnetic basement and model prominent magnetic anomaly. Analysis of Induce Polarization data were used in delineating the potential fractures zones of mineralization. Visual inspection of the magnetic anomalies and first vertical derivative maps reveals that the area is highly faulted with major faults trending East-West (E-W) and minor ones Northeast-Southwest (NE-SW) directions. The qualitative interpretation results of both the resistivity and chargeability pseudosections reveal potential fractures zones trending East-West (E-W) and the depth to the anomalous body ranges from (0.3-2.5 km) with average overburden thickness of 2.1 km. Two depth source models were interpreted using Discrete Fourier Transform method (spectral analysis) namely; the shallower sources which range from 0.45 to 1.49 km and the deeper ones which range from 1.81 to 3.24 km. The quantitative interpretation of the aeromagmatic data, depict that the average sedimentary thickness ranges from (2.3-3.2 km) and the average depth to the Curie isotherm in the area is 24.76 km. The result also shows that the Curie temperature isotherm within the basin is not a horizontal level surface, but is undulating. The regional average results for both geothermal gradient and heat flow across the study area are 23.07°C/km and 57.66 W/m² respectively. Based on the computed sedimentary thicknesses (2.3-3.2 km), the geothermal gradient (22.27 and 37.00°C/km.) and the prevalent fractures, the possibility of hydrocarbon accumulation in the northern and southeastern part of the study area is feasible whereas other parts of the study area with low sedimentary thicknesses will favour magnetic mineral deposits such as the prevalent oolitic iron ore deposits at Agbaja and Kotonkarifi axes.