Spectral Depths Estimate of Subsurface Structures in Parts of Borno Basin, Northeastern Nigeria, using Aeromagnetic Data

Abstract

Spectral depth analysis of aeromagnetic data covering latitude 12.00'N to 13.00'N and longitude 10.00'E to 11.00'E which corresponds to part of Borno basin, Northeastern Nigeria, was carried out for the purpose of investigating the sedimentary thickness beneath the surface. The study area was covered by 4 aeromagnetic maps. The aeromagnetic maps were digitized on a 3km grid and later complied to produce a combined aeromagnetic data file for the area. The data file comprises 1369 data points. Polynomial fittings method was applied in the regional residual separation. The residual map was later subdivided into 16 spectral sectors. The result of the study shows that the first layer depth was estimated to have a range from 0.18km to about 1.9km while the second layer depth was estimated to have ranged from 2.9km to about 4.2km. The highest sedimentary thickness of 4.2km occurred at the extreme northeast part of the study area and corresponds to areas around Gorgoram. These areas may be subjected for further geophysical method like seismic reflection/refraction, so as to ascertain its hydrocarbon potential.