NEW OCCURRENCE OF POLYMETALS MINERALIZED PEGMATITES IN THE OLDER GRANITOIDS, WADI EL SHEIH AREA, CENTRAL EASTERN DESERT, EGYPT.

Document Type : Original Article

Author

Nuclear Material Authority, P.O. Box 530 Maadi, Cairo, Egypt.

Abstract

New occurrences of rare metals- radioactive mineralized pegmatites are recorded Wadi El Sheih located along Qena-Safaga road Central Eastern Desert. The investigated pegmatites are exposed in the eastern and western banks of Wadi El Sheih. The rocks hosting the radioactive pegmatites are older granites of the type’s tonalite and granodiorite. According to the geologic investigations, petrographic studies, radioactivity and mineral compostion, the studied radioactive pegmatites comprise three categories, namely weak 800 to 1000 Cps (WRP), moderate 1000-2500 Cps (MRP) and high radioactive pegmatites 2500 up 12500 Cps (HRP) types. The WRP and MRP are modes of occurrence generally occur as small to medium vein, dyke, rounded and elliptical unzone and occasionally zoned pocket and lenses types. The mineralized bodies of WRP type located in NNE-SSW, NE-SW intersection, while MRP types are mainly occurring at the intersection of and E-W and NE-SW fault trends. The HRP type occurs as a large size up to few meters, pockets of elliptical to irregular shape, and its radioactive anomalies are mainly controlled with intersection of both NNE-SSW and NE-SW with E-W trends. The petrographic and mineralogical studies revealed that WRP type is bearing zircon, allanite and titanite, while the MRP possesses uranthorite and zircon. The HRP type displays enrichment of the high radioactive minerals contents namely, aeschynite and nioboaeschynite with accessories illemenorutile, allanite and uranothorite. Aeschynite and nioboaeschynite minerals have the high U and moderate Th values compare to other identified radioactive minerals.

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