Structural investigation of Zungeru-Kalangai fault zone and its environ, Nigeria using aeromagnetic and remote sensing data

Abstract

This study analysed aeromagnetic and satellite imagery data over parts of northern Nigeria to delineate magnetic and surface lineaments associated with fault system trends. The aeromagnetic data were analysed using the Fast Fourier transform technique for reduction-to-equator, total horizontal derivative, analytic signal amplitude and Euler deconvolution. Landsat-8 OLI and SRTM data have been enhanced using spatial filtering and hill-shading techniques for the delineation of lineament features. The extracted surface lineaments are denser on the satellite imageries than on the HRAD because the datasets respond to different physical properties of the geological units and features. The location and orientation of the Zungeru/Kalangai fault zone, which extends about 245 km from the Bida Basin Basement to the northern part of Nigeria, correlate with the existing fault on the published geological map and form a conjugate pair with a fault around Kaya. The derived maps revealed the presence of several previously undetected geological lineaments corresponding to faults and folded dyke, striking predominantly N–S, NNE-SSW, NE-SW and NW-SE lacking in previous geological maps. The application of 2D forward modelling revealed the 2D image of the nature of the subsurface, magnetic susceptibilities of rocks and the block boundaries coinciding with the geological lineaments.

Keywords

• Modelling
• Subsurface structures
• Remote sensing
• Aeromagnetics
• Fracture zones
• Source edge detection