Analysis of aeromagnetic anomalies of parts of Chad Basin, Nigeria, using high-resolution aeromagnetic data

Abstract

High-resolution aeromagnetic data over a part of Chad Basin in Nigeria have been analysed with a view to delineate the geological lineaments, estimate sedimentary thicknesses and map the location of structurally controlled sub-basin formation within the studied area. The geological lineaments were mapped using horizontal gradient magnitude method. Spectral analysis and source parameter imaging (SPI) techniques were used to estimate the sedimentary thicknesses. The results revealed the existence of structurally bounded large depression that dominantly spans the south-eastern portion of the study area. The depression is interpreted as a large structurally controlled sub-basin having a width of about 79 km and extending to over 5.7 km in depth from the result on SPI. The depth estimated from spectral analysis shows depth estimate of 1.2–4.8 km. The application of forward modelling revealed the 2D image of the nature of the subsurface (basement morphology and the depths) and the block boundaries coinciding with the geological lineaments. The models also show some areas within the sub-basin extending to a depth of 8.3 km. The maximum depths obtained from the SPI and 2D models (profiles N1–S1 and N3–S3) show a structurally controlled sub-basin sufficient for potential hydrocarbon generation and accumulation.