By wp_update-1701710083
Southern Nigeria has major and minor sedimentary basins. This study covers parts of 5 sedimentary basins in southern Nigeria, this includes the Niger Delta, Benue Trough, Calabar Flank, Mamfebasin and Lower Benue Trough. Aeromagnetic data has been used by many authors worldwide in evaluation of subsurface basin configuration. This study covers parts of five basins (Niger Delta, Calabar Flank, Anambra Basin, Mamfe Basin, and Lower Benue Trough) in Nigeria. The study utilized twenty aeromagnetic maps on a scale of 1:100,000. The maps were digitized manually along flight lines and a total of 16,689 data points obtained. The data was processed using computer techniques including map merging, reduction to pole, polynomial and power spectrum filtering for residual and regional anomaly separation, and forward and inverse 2.5D Saki modeling. Results obtained from power spectrum depth analysis indicate depth to magnetic sources vis –a –vis sediment thickness from the Niger Delta area (2.75 km -3.75 km), Anambra basin (1.5 km –2.6 km), Calabar Flank (1.3 km –2.3 km), Mamfe basin (2.0 km –3.4 km), and Lower Benue Trough (1.5 km –3.2 km). Also, depth to basement results from forward and inverse modeling indicate the Niger Delta has thickness of sediments ranging between 1.0 km-8.0 km, Anambra basin (1.4 km –2.7 km), Calabar Flank (0.8 km-2.5 km), Mamfe Basin (1.0 km –2.7 km), and Lower Benue Trough (1.4 km –2.7 km). Also, results from modeled number of intrusives indicate that the Calabar Flank has five intrusives, Niger Delta has four intrusives, Mamfe basin has six intrusives, Anambra basin has five intrusives, and Lower Benue Trough has four intrusives. The implications of the increased number of intrusives are that generated hydrocarbons might be converted to gas, this is more likely in areas around Calabar Flank, Mamfe basin and Anambra basins, given the high number of occurrence of intrusives within these areas. Whereas areas around the NigerDelta and Lower Benue Trough with significantly increased depth and lower number of intrusive are less prone to excessive heat from the intrusive and may produce more oil. The study support further exploration activities within the Niger Delta and Lower Benue Trough areas. The significance of this study is the wide range appraisal of the basin architecture and configuration of the offshore and inland basins in Southern Nigeria. The Niger Delta basin areas of Portharcourt, Bonny with sediment thickness of about 8.0km and less occurrence of intrusives has the highest hydrocarbons exploration potentials. The Bansara area within the Mamfe basin has (2.6 km) sediment thickness that could generate hydrocarbons given that another condition is favourable, but the presence of numerous intrusives may make the area prone to excessive heat and may produce more gas than oil. The Anambra basin and the Lower Benue Trough have a moderate depth of sediments thickness(2.5km) and less number of intrusives, these areas came second to the Niger Delta among the studied basins for good prospects in hydrocarbon exploration investigations. It is concluded that this study reveals the order of preference of the choice of investigating the hydrocarbon prospective potentials of Southern Nigerian basins using the potential field magnetic method, it is recommended that other geophysical methods such as gravity, and seismic be used to identify possible hydrocarbon habitats within the Southern Nigeria Basins.
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