Abstract
<title>Abstract</title> <p>Gold has been reported in the crystalline basement complex of the South Sudan Equatoria region. Over the years, little systematic work has been done to understand the geological context of these deposits, including their origin and host rock. This paper focuses on the Kapoeta alluvial deposit within the Karasuk Supergroup of the Arabian Nubian Shield in southeastern South Sudan. In this study, we use an integrated approach comprising Landsat (ETM + and OLI) imagery, Shuttle Radar Topography Mission (STM) digital elevation model data, and field investigations and validations to address this question. By applying image processing techniques, including false color composites in RGB mode, principal component analysis (PCA), band ratios, and minimum noise fraction (MNF), we map the main lithological units and outline the main structural features and their orientations in relation to regional tectonics. The relationship between the geological framework and gold mineralization in the area is examined. Certain band combinations were significant in mapping lithological units and structural features. Band ratio techniques were employed to map specific mineral ratios (e.g., 4/2, 6/5, and 6/7) and identify areas of oxide and clay concentrations associated with alteration. The PCA approach (e.g., PCA 1 and 4) was instrumental in delineating lithological and structural features in the area, whereas the PCA composite bands were used to identify both lithological and alteration zones. The results of the processed satellite scenes were validated via field mapping and sample collection from outcrops. This integrated approach of remote sensing and field mapping demonstrated the effectiveness of mapping lithological units and structural features in areas covered by sediments and can be replicated in similar settings. Landsat imagery is effective at mapping alteration zones associated with mineralization in the area.</p>