Primary uranium mineralization in sheared pegmatite of Wadi El Regita, South Sinai, Egypt

Document Type : Research and Reference

Authors

1 Nuclear Materials Authority, P.O. Box 530, Maadi, Cairo, Egypt

2 Department of Geology, Faculty of Sciece, Zagazzig University, Zagazig, Egypt

Abstract

An important sheared pegmatite zone is hosted by the monzogranite of Wadi El Regita area, South Sinai. This shear zone has an elongated shape with N 80ο W trend and includes numerous highly altered spots. It is considered as the highest measured radioactive shear zone recorded in the area.
Based on field ground ɣ-ray spectrometric survey of the sheared pegmatite zone, 4 contour maps were compiled for total count (Tc), eU, eTh and eU/eTh ratio. The pegmatite shear zone is characterized by high levels of radiometric measurements especially along its strike. The obtained maps exhibit the presence of three main anomalies associated with the highly altered spots and mostly due to the presence of radioactive minerals e.g. brannerite, pitchekitery, davidite and uraninite minerals, which are recorded for the first time in Sinai by the first author (Bishr, 2007).
The different minerals had been identified based on their radioactive and physical properties as well as X-ray diffraction (XRD) and Scanning Electron Microscopy (XL30-ESEM, Philips) attached with EDAX unit. The ESEM analyses indicate the presence of brannerite, orthobrannerite, petscheckite, liandratite, uraninite, pyrochlores and columbites minerals. The average uranium contents of all the studied primary minerals grains vary from 12.73 to 82.87 wt%. Overall, Ce was the most abundant LREE in these grains. The Ce contents vary from 1.1 to 6.19 wt% and Nd varies from 0.15 to 2.35 wt%.
The major factors controlling the distribution of uranium mineralization within the studied sheared pegmatite are fracture system developed through the zoned pegmatite body during the course of the hydrothermal solutions migrated from deeper source through the structural weaknesses of the shear zone.