Application of Alpha-Track Mapping to Genesis of Uranium-Mineralization, Gabal El-Bakriya, Eastern Desert, Egypt

The Solid State Nuclear Track Detector (SSNTD) Kodak-CN-85 was used to show the genesis and distribution of the radioactive element in Gabal El-Bakriya different granitic and U-mineralized granitic varieties. In the non mineralized granites the track mapping showed that U and Th are confined mostly to the accessory U-bearing minerals such as epidote (allanite), zircon and opaque. In the U-mineralized hydrothermally altered granites, the alpha tracks showed that the u and Th are displayed by (Fe, Mn) oxides filling the grain fractures, interstitial micas and associated fluorite and amorphous silica filling vugs and fractures. Fluorite may also display alpha-tracks probably due to minute radioactive inclusions. Uranium-fixation followed the hydrothermal stages causing desilicification and muscovitization of biotite and feldspars and accordingly U, F, Fe and Ca were liberated. The Fe-oxides adsorb U and Ca reacts with F to form fluorite. Excess Ca reacts with uranyl ions presence of amorphous silica to form uranophane, which is deposited as thin films along fractures. Also the minute radioactive inclusions such as zircon, columbine and allanite are liberated from micas and may later be included into the newly formed fluorite