Delineation of Mineralization Zones in Part of Central Nigeria Using Analytic Signal, Second Vertical Derivative, and Centre for Exploration Targeting Plug-IN (CET)

Abstract

A digitised aeromagnetic data comprises of sheets (144 Kakuri, 145 Kajuru, 165 Bishini, 166 Kachia, 186 Abuja, 187 Gitata, 207 Kuje and 208 Keffi) covering part of Niger, Kaduna, Nasarrawa and the Federal Capital Territory in central Nigeria with an area of  was acquired and analysed with the aim of delineating mineralisation zones within the area using analytic signal, second vertical derivative and structural complexity analyses of the CET. From the analytic signal map three zones were delineated; Low to fairly low magnetic zone (LM) with a gradient of 0.0024 nT/m to  0.0093 nT/m are areas associated with highly weathered rocks and areas with thin cover of sediments, metasediments, and granite because these rocks contain more than 60 to 70 percent quartz. The moderate zone (MM) with gradient 0.0093 nT/m to 0.04 nT/m associated with granite – gneiss as these rocks contain high ferromagnesian with low amount of felsic minerals. The high magnetic anomalies zones (HM) 0.2378 nT/m to 0.02349 nT/m are related to rocks that have high ferromagnesian with large amount of felsic minerals. Application of Second Vertical Derivatives (SVD) filter produces a map in which prospective zones of mineralisationsand structures were mapped out. These mineralisation zones were seen to be concentrated in areas with high analytic signal of gradient0.2378 nT/m.Application of structural complexity analysis due to CET located deposits occurrence favourable zones that coincided with zones mapped out from SVD map. Structural trends as revealed by CET Plug-IN are NE-SW, NW-SE, minor E-W and N-S trends.