Depth to magnetic basement in the Anambra Basin, Benue Trough of Nigeria from aeromagnetic data: A prelude for hydrocarbon exploration

Abstract

Data transformation, regional-residual separation, trend analysis, and analytic signal (AS) depth estimation were applied to aeromagnetic data covering the Anambra Basin, which is a major depocenter in the Benue Trough, southeast Nigeria, with the primary objectives of accentuating the attributes of magnetic sources and determining if sufficient sediment thickness exists for hydrocarbon generation, maturation, and expulsion. The application of data transformation techniques (such as map projection, merging, and reduction-to-pole) and regional-residual ensured the computation of a crustal magnetic field that would be suitable for magnetic analyses. Results indicate that the magnetic basement in the basin forms an undulating surface overlain by sediments with an average thickness ranging between 4 and 7.5 km, whereas the maximum thickness reaches 8 km in some areas. This depth range suggests a promising prospect for source-facies maturation and expulsion. We expect that areas in the study area with these appreciable sediment thicknesses, good preservation of graben fill, and suitable areal closures or fault structures would be favorable for hydrocarbon prospectivity.