Petrographic and Mineralogical Features of the Uraniferous Pink Granites in the North Eastern Desert of Egypt

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Petrographic and Mineralogical Features of the Uraniferous Pink Granites in the North Eastern Desert of Egypt
M.Y. Atawiya*, A.B. Salman**, R.M. ElBayyomi** and M.Khalaf*

* Nuclear Materials Authority
** Geology Department, Faculty of Science, Ain Shams University

Abstract

The present work is concerned with the petrological, mineralogical and geochemical studies of some uranium bearing younger granites in the north Eastern Desert of Egypt particularly Gebel Gattar area.The area around Gebel Gattar comprises the following rock units (starting from the oldest): metavolcanics, diorite-grano-diorite complex-Dokhan volcanics- Hammamat sediments, younger granites and dykes. Themost significant structural features are represented by NNE-ENE dominantly trending faults and joints.Petrographicaly, the pink granites are divided into normal and mineralized (uraniferous) granites. Normal granites are classified into threetypes; a) leucocratic perthitic granite, b) hornblende-biotite perthitic granite and c) two feldspars perthitic granite. Mineralized granites are sheared,deformed, pinkish brown in colour and strongly altered. A remarkable secondary uranium mineralization has been recorded along fault and fracture zones.X-ray diffraction analysis indicated the presence of uranophane, beta-uranophane and kasolite as secondary uranium minerals. The uranium mineralizations are associated with strong hematitization, kaoliriization,sericitization, fluoritization and carbonatization. Moreover, hematite,ilmenite, biotite, zircon, wulfenite, molybdenite, pyrite, chlorite and phlogopite are found with uranium minerals. Wulfenite mineral is recorded for the first time in Gattar mineralized granites.