Aeromagnetic Anomalies Modeling and Their Tectonic Implications in the Middle Benue Trough, Nigeria

Abstract

The middle Benue Trough has been studied on a reconnaissance stage, no detail subsurface modeling to reveal basin configuration has been undertaken. Twelve(12) Aeromagnetic maps on a scale of 1:100,000, covering the middle Benue Trough were digitized and processed using computer techniques which include; map merging, polynomial filtering, power spectrum, forward and inverse modeling. Eight (8) profiles were modeled to determine the structure of the basin and the presence of possible intrusives. The results indicate the presence of twenty three (23) intrusives; seven (7) are basaltic while sixteen (16) are rhyolites. The Saki model configuration reveals average sediment thickness ranging between 0.5 – 4.0km, these represent horst and graben structures. These variations are also revealed in the power spectrum depth estimate, which shows a range between 1.2 – 2.7km. The Doma and Agana areas have the largest accumulations of sediment thickness (0.5 – 4.0km) covering about 40km, other areas have shallow depths (0.5 – 2.0km), and cover distances between 19.5 – 23.8 km, these later areas are less favorable for hydrocarbon accumulation. The Doma and Agana areas remain the most favorable areas for hydrocarbon exploration based on their thick sediment accumulation. However, these areas reveal the presence of seven (7) intrusives; this may cause high geothermal temperatures that may not be favorable for hydrocarbon accumulation.

Keywords: reconnaissance,forward and inverse modeling,configuration,intrusives