Studies of radioactive minerals and geochemistry of uranium at the granitic rocks of Wadi Um Shillman Area, South Eastern Desert, Egypt.

This article focuses on the uranium occurrence, mineralogy, and geochemistry of the northwestern part of the Gabal Um Ara granitic pluton in the southeastern desert of Egypt. The area, characterized by post-orogenic monzogranite and alkali feldspar granite intrusions, exhibits several radioactive anomalies near contacts with Dokhan volcanic and metavolcanic rocks, with uranium mineralization primarily along fractures in sheared alkali feldspar granite. Secondary uranium minerals identified include uranophane, β-uranophane, and kasolite, associated with accessory minerals such as fluorite, zircon, columbite, and spessartine garnet. Geochemical analysis shows enrichment in mobile elements like rubidium (Rb), thorium (Th), and uranium (U), with evidence of secondary uranium enrichment influencing the Th/U ratio. The study suggests a hydrothermal origin for the uranium mineralization, controlled by structural features and alteration processes.