Enhanced geological and radioactive mapping of Gabal Abu Ashayir-Gabal El Bakriyah area, central Eastern Desert, Egypt, using remotely sensing data

Abstract

The primary goal of this work is to integrate airborne gamma-ray spectrometry with multispectral data from ASTER and Landsat-8 for mapping of the geology, radiometric data, and types of alterations of Gabal Abu Ashayir-Gabal El Bakriyah area, central Eastern Desert, Egypt. Utilizing various image processing techniques like color band composites (CBC), principal component analysis (PCA), band ratios (BR), and minimum noise fraction (MNF), it is possible to map the hydrothermal alterations zones and identify the lithological units under investigation. By identifying the various lithological units and alteration types, these results are validated and verified in the field. These methods’ outputs are combined to create an accurate geological map of the research region and tracing the propylitic, phyllic and iron oxy-hydroxides alterations. These rock units are ophiolitic mélange (oldest), arc metavolcanics, arc granitoids, younger gabbro, late-collision granites (monzogranites, syenogranites and alkali feldspar granites) and Nubian Sandstone (Taref formation and Quseir Formation) youngest, Furthermore, the radioactive anomalies are primarily associated with ferrugination zones (iron oxy-hydroxides alteration) at Gabal El Bakriyah monzogranite and alkali feldspar granite. The radioactive minerals are uranothorite, thorite and fergusonite. The opaque minerals that encountered at the rock units of Gabal Abu Ashayir-Gabal El Bakriyah are chromite, ilmenite, magnetite, chalcopyrite and chalcocite, whereas the non-opaque minerals comprises titanite, rutile, fluorite, garnet, zircon, apatite and barite.