REMOTE SENSING, GEOLOGY AND GEOCHEMISTRY ON THE GVIII URANIUM MINERALIZATION, GABAL GATTAR, NORTH EASTERN DESERT, EGYPT

GVIII- uranium occurrence of Gabal Gattar is located at the intersection of Lat. 27º 05′ 56″ and Long.
33º 16′ 33″ to the south of GII-uranium occurrence. This occurrence is hosted in the alkali feldspar granite
of Gabal Gattar. It is dissected by NNE-SSW, ENE-WSW and NW-SE faults and fractures. The granite is
strongly altered in the zones of these faults and fractures. This granite is composed of K-feldspars, quartz,
plagioclase and biotite as essential minerals and zircon, apatite, fluorite as accessories. The secondary
minerals are chlorite, sericite, muscovite and iron oxides. The main alterations along the fault and fracture
zones are hematitization, silicification, kaolintiization, chloritization and fluoritization that increase at the
zones of intersection.The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER)
discriminated and mapped the hematitized zones in the studied granitic rocks predicting iron oxides as
pathfinder minerals that be helpful in localizing high uranium concentration. The compilated and integrated
data as alteration zones, geological and structural features using Geographic Information System (GIS)
played an important role in correlating, manipulating, visualizing and extracting the information getting a
better result for interpretation and evaluation of this occurrence. The study granite is geochemically, alkalifeldspar
granite to syenogranite originated from weakly peraluminous magma of alkaline affinity and of
within plate tectonic setting due to crustal relaxation. This granite shows many geochemical characterestics
similar to the A-type granite, high contents of SiO2 , (Na2O + K2O), Rb, Nb, Y, low contents of MgO,
CaO and Sr and apparently F-rich granite.Radiometric measurements of GVIII U-occurrence show that the
study granite records uranium values between 15 and 28 ppm, while the anomalies record uranium values
range from 400 to more than 30000 ppm. Surfacial yellow secondary uranium mineralization was recorded
closely to the altered hematitized zones. Environmental Scanning Electron Microscope (ESEM) and XRD
techniques recorded secondary uranium minerals as uranophane and U-bearing accessory minerals as
columbite, betafite, zircon and violet fluorite.