An integrated analysis of aeromagnetic and PRISMA hyperspectral imagery data for potential gold mineralization exploration in Mwanza, Malawi

Abstract

Potential zones of gold mineralization in Mwanza, Malawi, were mapped by employing an integrated analysis of satellite imagery and aeromagnetic data. PRISMA hyperspectral imagery satellite was used to map hydrothermal alteration minerals by employing linear spectral unmixing (LSU), spectral angle mapper (SAM), and spectral information divergence (SID) mapping techniques. Aeromagnetic data was used to map the structures using the Centre for Exploration Target (CET grid and porphyry analysis) and depth estimation using spectral analysis. The evaluation of LSU, SID, and SAM effectiveness showed an overall accuracy (OA) of 86.288% and a Kappa coefficient (ҡ) of 0.825, an OA of 82.042% and ҡ of 0.770, and an OA of 80.675% and ҡ of 0.753, respectively. The mineral maps revealed that the alteration zones mainly consist of kaolinite, indicating the potassic and argillic alteration types. About six zones that showed potential for mineralization were identified from the integrated analysis. The structures in the area were found to trend NE-SW dominantly, and the depth range to basement complex rocks, which host potential mineralization veins, was found to be 90.33–1416.40 m. Limited chemical data of quartz veins shows an average of 0.2 ppm gold anomalies from the identified zones. The suspected gold-bearing quartz veins have been observed to be in association with the gneisses and migmatites that make up the basement complex rocks in the area. A comprehensive study encompassing geological and geochemical surveys and analyses is required to ascertain its complete gold potential.