Integrated Geophysical Investigation for Potential Gold Mineralised Zone within Lower Part of Zuru Schist Belts, NW Nigeria

Abstract

The study began with a reconnaissance survey that used high-resolution aeromagnetic data of the study area to identify suitable structure zones with the potential to trap mineral resources within the context of the gold exploration target. The findings of magnetic studies were followed up with detailed investigations using 2D electrical resistivity tomography (ERT) and induced polorisation (IP) techniques to reveal further details about gold mineral zones and other lithological boundaries. The airborne magnetic data of sheet 118_Yelwa was obtained from the NGSA; these datasets were processed and analyzed using Oasis Montaj's first vertical derivative (FVD) and center for exploration targeting (CET) techniques. Results of FVD and CET grid anomalies show that regions of major magnetic structures (lineaments) are associated with granite gneiss, migmatitic augen gneiss, and medium to coarse-grained biotite when compared to the geological settings of the area. The zones of major structures obtained in this study coincided with previous magnetic studies of the area, located in the eastern parts of Ngaski, Yauri (Yelwa), Shanga, Agwara, as well as Magama's northwest region. Some of the regions for lineament (in the eastern part of Ngaski/Yauri) were investigated further with 2D ERT and IP detailed geophysical methods in a dipole-dipole configuration. The results of geoelectric techniques along profiles 1, 2, and 3 identified the major gold mineralisation potential zones, which were labeled A1, A2, and A3. These regions have low/high resistivity (1.6 to 459 Ωm/1889 to 7773 Ωm) and chargeability signatures (≥ 20 msec), and could thus be interpreted as potential target zones for metallic mineral exploration, particularly gold mineralisation. The regions are located in the northern Mararraba and southwest of the Jinsani areas of Kebbi State. The results of integrated geophysical methods have produced updated structural features of the regions, as well as a database containing precise locations, lateral lengths, thicknesses, and depths for prospective gold mineralisation zones. This database could assist the miner/explorer in locating the potential zone of gold mineralisation.