Geophysical Magnetic Data Analyses of the Geological Structures with Mineralization Potentials over the Southern Part of Kebbi, NW Nigeria

Abstract

This study used geophysical data analysis to map and provide useful estimates of the geometry, depth, and magnetization of the magnetic sources, as a continuation and improvement over the earlier anal-yses in the area. Fugro airborne surveys collected aeromagnetic data for the Nigeria Geological Survey Agency (NGSA) between 2009 and 2010. The study area’s data were processed and analyzed using an im-proved tilt derivative (TDR) technique and 2D magnetic structural modelling. The result of TDR reveals the horizontal location and extent of the edges of various magnetic sources that formed lineaments. The results from 2D modelling for the selected profiles (PI, P2, P3, P4, and P5) identify zones with a high magnetic anomaly responding to fractures. These fracture regions of the basement complex area could be caused by fault/shear zones. Fault-induced areas on these sub-basin floors are important hosts for hydrothermal miner-alization. In comparison to the geological setting, these regions are underlain by quartz-mica schist, biotite-hornblende, granite, biotite, gneiss, diorite, migmatite, medium coarse-grained sandstone, ironstones, laterite, siltstones, and clay. These regions could be suitable for mineral exploration and correspond to the Ngaski, Yauri, Magama, Shanga, and Rijau. However, in comparison to the SPI results, the depth/thickness of the sediments that crossed the areas of the sedimentary basin and basement complex zones did not match the results of 2D forward modelling. The SPI technique usually provides an average depth of the magnetic source and is unable to accurately map the undulating basement. While the aforementioned results of 2D forward modelling provide sediment thickness by accurately reflecting basement topography.