Integrated geological mapping approach and gold mineralization in Buhweju area, Uganda

摘要

Deeply dissected mountainous ridges, paucity of exposure, deep weathering, extensive regolith, dense vegetation cover and poor accessibility, are detrimental to conventional field geological mapping. Conditions such as these, characterize our current study area; the Buhweju area in Uganda. The latter is poorly explored and known to host alluvial gold. In this work, an integrated geological mapping approach aiming at updating the geology, building relationships between the lithology and structure and assessing its control on mineralization was tested using Landsat TM, shuttle radar topographic mission (SRTM) and potential filed datasets (radiometrics and magnetics) subsequently validated by field investigations. Several image processing and enhancement techniques were applied that improved the aesthetic quality of the various remotely sensed datasets for visualization and interpretation. Among the image enhancement techniques, image fusion and pan-sharpening of the radiometric composite image with multispectral data and SRTM digital elevation model (DEM) have resulted in better lithological differentiation. In general, the present work, found complementarity in lithology with the legacy geological map. On the basis of similar radiometric signature however, various basement rock units such as pelitic schist, quartzo-feldspathic gneiss and granite were delineated and mapped; some in areas which were not reported before. These were validated during field investigation. Similarly, the aeromagnetic data depicted worthwhile information regarding litho-magnetic domains and tectonics of the Buhweju study area.