Influence of Pan-African tectonics on older Precambrian basement structural fabrics as revealed from the interpretation of aeromagnetic and remote sensing data of Ikole/Kabba region, southwestern Nigeria

Abstract

Reliance on structural data from geological mapping will be grossly inadequate to establish an informative regional tectonogenic interpretation in southwestern Nigeria mainly because of poor exposure of outcrops due to severe weathering in the tropical region. Therefore high resolution aeromagnetic anomaly and Landsat-8 OLI/TIRS data were adopted for tectonic analysis of Ikole/Kabba area where qualitative analysis of Landsat-8 imagery provides surface lineaments with major E − W and N–S trends. Processing of the aeromagnetic anomaly data utilizing the horizontal gradient magnitude and total gradient methods indicated various E − W, NW - SE, N–S and NE - SW structural features in agreement with the surface lineaments; lending credence to the existing geologic structural interpretation. The resulting synoptic structural interpretation suggests the preservation of two major successive events; an earlier prominent E-W trending lineaments resulting from a N–S compressional deformation, succeeded by a brittle deformational event characterized by NW-SE and NE-SW trending lineaments. Additionally, the magnetic basement depth map deduced from the source parameter imaging technique shows depth values between 50 m and 650 m, which represent depths to the top of structural features within the basement rocks of the region. The collective interpretation of high resolution aeromagnetic anomaly and Landsat-8 data provides significant information about regional tectonics and structures that are good conduits for mineral deposits within the study area.