Geophysical Assessment of Basement Depth and Sediment Thickness in the Gongola Basin, North East Nigeria

The Gongola Basin in North East Nigeria is a sub-basin of the Benue Trough that has been the subject of intermittent hydrocarbon exploration, yet basin-scale basement depth mapping using modern data integration methods is incomplete for the northern sector. This undergraduate study interprets available aeromagnetic and gravity data to estimate basement depth and sediment thickness across the northern Gongola Basin in Adamawa and Gombe states. Spectral analysis of aeromagnetic data was applied to estimate mean depths to the top of the magnetic basement over grid cells of appropriate size. Bouguer anomaly data were subjected to 2D gravity inversion along five regional profiles to produce basement geometry models. Euler deconvolution of the aeromagnetic data provided point-source depth estimates confirming spectral analysis results at key control locations. The combined basement depth estimates range from 0.5 kilometres at exposed basement highs at the basin margins to approximately 4 kilometres at the basin depocentre. A NE-SW trending basement ridge interpreted as a horst block divides the northern basin into two sub-depressions of contrasting sediment thickness. The estimated maximum sediment thickness is consistent with previous gravity modelling results and with the reported depths of exploratory wells drilled in the southern part of the basin. The study provides an updated subsurface framework for the northern Gongola Basin useful in regional petroleum system analysis. Keywords: Gongola Basin, basement depth, aeromagnetic, gravity, sediment thickness