Geologic structures associated with gold mineralization in the Kirk Range area in Southern Malawi

Abstract

Abstract In this contribution, we use a newly acquired high-resolution airborne geophysical data set and field geological investigations in the Kirk Range area in southern Malawi to understand structures that control gold mineralization. Gold in this area is alluvial, mined by artisanal miners and detailed information regarding the structures controlling primary mineralization remains sparse. Structural interpretations are afforded by in-depth investigation of airborne magnetic and radiometric data, which are then supported by ground geological mapping and by microscopic observations using X-ray computed tomography (XCT) and optical microscopy. The results show that the Kirk Range displays extensive faulting and shearing with a NE–SW trend as the prevalent structural grain of the region. Gold mineralization is hosted in NE–SW trending structures. The wall rock alteration associated with gold mineralization results in a pronounced K/Th anomaly, which is suggested as an important radiometric guide for future exploration efforts. Exploration in the Kirk Range region should focus on the NE–SW structures, which represent potential conduits for fluid flow.