An interpretation of total intensity aeromagnetic maps of part of southeastern Sokoto basin

Abstract

The total magnetic field intensity maps of part of south-eastern Sokoto basin (1: 100,000 sheets 29, 30, 51 and 52) were digitized and processed. A composite total magnetic field intensity map of the four sheets was produced. Regional-residual separation, second vertical derivative calculation and two-dimensional spectral analysis were carried out. The residual field map and second vertical derivative (SVD) map showed discontinuities some of which coincide with the geological boundaries between marine sediments of Maastrichtian (Sokoto Group) and Palaeocene (Rima Group) and sediments of Quaternary (Illo/Gundummi). The two-dimensional spectral analysis indicated a two-depth source model. The deeper sources occurred at the depth of 1.25km - 1.80km while the shallower sources occurred at the depth of 0.31km – 0.56km. The deeper sources probably represent depths to the Pre-Cambrian basement and the shallower sources probably represent depths to the magnetized bodies within the sediments. The surface plot of the depths to the basement shows some narrow depressions in the basement, which constitute sub-basins. The faults and fractures are potential channels for mineralization fluids. The sub-basins can play host to sedimentary mineral deposits.