Remote sensing techniques for mapping hydrothermal alteration zones of volcanogenic massive sulfide deposits in Red Sea Hills, NE Sudan

Abstract

The area of our research lies in the Red Sea Hills region in NE Sudan and occupies a central position in the Nubian part of the late Proterozoic Nubian-Arabian Shield. The Red Sea Hills have received considerable studies in structural and remote sensing aspects in the past decades. Most of the studies were conducted to understand the structural evolution and the tectonic development of the Nubian-Arabian Shield in northeast Sudan. However, the link between the structural elements and the mineralization in the area is not well established, and in several parts of the region the identification of mineral deposits is also not well known. Therefore, the present study deals mainly with the determination of mineralization zones and highlights the structural elements of the study area. The processing of Landsat 8 OLI images has included different methods such as band rationing, density slicing, and featured oriented principal component analysis. These methods allowed us to identify the zones of hydrothermal alteration, which could be associated with ore mineralization within the study area. These mapped alteration zones were verified with the aid of the obtained field and geochemical data. Interpretation of the detailed geochemical data set of the study area revealed the presence of Au/Cu/Zn anomalies at most of the perspective locations outlined in the hydrothermal composite map, uniquely supporting the usefulness of remote sensing methods. The structural analysis of the brittle deformation manifestations revealed that the NE–SW fracture system represents the main controlling factor on the occurrence of the mineralization in our research area.