Analysis of recent airborne gravity and magnetic data for the interpretation of basement structures underneath the south-western Benue trough using source edge detector filters

Abstract

We present the detail basement and trends of geological structures associated with the Mesozoic-Cenozoic volcanism in the south-western region of the Nigerian Benue trough using recent gravity and magnetic anomalies of the region. The analysis aimed at recognizing and mapping the basement structure that controlled the distribution and source host of hydrocarbon and other economic mineral resources in the region. The structural recognition and mapping is done on the basis of the utilization of the Tilt Angle (TA) and Total Horizontal Derivative of the Tilt Angle (THDTA) of gravity and magnetic data. From these techniques, we have been able to identify and mapped out those edges of anomalous sources due to the gravity and magnetic data that are in association with the basement geological structures of the area. Based on the mapped structural trends, it is observed that the basement structures derived from both the gravity and magnetic anomalies correlated well with the zones of volcanic rocks around Gboko and area between Lefin and Oturkpo. The two locations are sitting over gravity and magnetic highs suggesting high density and susceptibility material below the subsurface. The Euler deconvolution method suggested depths between 1 and 5 km from both gravity and magnetic data. Deeper basement of anomalous sources are suggested between 3 and 5 km. The 1 km depth interprets the regions of basement highs or corresponding to intrusive zones.