Lithological and Alteration Mapping at the Um El-Rus Area, Central Eastern Desert, Egypt, Using Remote Sensing Techniques

Abstract

The present study aims at discriminating the rock units and mapping the alteration zones from their host rocks, as promised targets for mineral exploration in Um El-Rus area using the widely considered ASTER data. Several remote sensing techniques were integrated for the lithological discrimination and alteration zone delineation. The approach methodology was able to map the various rock units and define the contacts between them precisely. Moreover, the spatial abundances of the alteration minerals (e.g., alunite, iron oxides, chlorite, kaolinite, illite, montmorillonite, and sericite) were mapped as an indication of the occurrence of alteration zones. More addition, the lineaments in the study area were extracted automatically using the PCI Geomatics software. Areas with considerable lineament density may indicate high potentiality for mineralization as these lineaments may represent faults and fractures that are the main channel ways for hydrothermal solutions to migrate through. This study yielded a modified geological map with enhanced lithological boundaries depending on the remote sensing data. Five localities were delineated and regarded as alteration zones with high potentiality for mineralization. A field visit was conducted to the study area through which the obtained results were validated. Field observations maintained the high accuracy of the obtained enhanced lithological map. During the field study, several alteration indicators were observed, including, quartz veins/veinlets, kaolinitization, chloritization, sericitization, and carbonatization types of alteration. The adopted alteration mapping methodology enabled the delineation of the already existing Um El-Rus gold mine; this validates the results as well.