Genetic link between uranium mineralization and the emplacement of limited intrusion adjacent to alkaline granites, Abu Hamr area, north Eastern Desert, Egypt

  • Osama K. Dessouky
Original Paper


The recorded uranium mineralization is genetically related to the U content and structural setting of syenogranitic dyke that occurs near alkaline granites, Abu Hamr area, north Eastern Desert of Egypt. The associated abnormal level of radioactivity exhibits maximum equivalent uranium (eU) of 155.6 parts per million (ppm) with an average of 54 ppm while the maximum of eTh reaches up to 235 ppm with average content of 120 ppm. The nearby alkaline granites of Gabal Abu Hamr show a normal distribution of eU and eTh resembling that of normal granites (4 ppm eU and 8 ppm eTh). Radioactive anomalies can be interpreted as successive concentrations of U-Th, which are related to magmatic processes of syn-shearing syenogranite dyke formation followed by hydrothermal redistribution during the emplacement, and then supergene enrichment. Testing of uranium equilibrium has revealed major chemical U addition to both the syenogranitic dyke and, to less extent, the alkaline granites. The rare-earth element (REE) patterns display pronounced enrichment of light REEs and heavy REEs of the syenogranitic dyke in contrast to the alkaline granites, which might have attributed to the subsequent hydrothermal circulation. The studied dyke is also characterized by well-developed U, Th, and Pb enrichments. Post-magmatic hydrothermal activity is evident from the presence of dark violet fluorite with inclusion of U and Th minerals, in addition to the presence of zircon crystals with overgrowth, xenocrystic cores, REE replacements, and spatially inclusions of allanite-(Ce) with irregularly distributed patchy overgrowths of U and Th.


Radioactivity Geochemistry Dyke emplacement Alkaline granites Egypt 



The author would like to thank Professor A. Omran for his help during the field work. The author is greatly indebted to Professor A. Dardier and Professor A. El Mowafy, Nuclear Materials Authority of Egypt (NMA), for their helpful discussions and constructive comments throughout the entire work. The author wishes to express his sincere thanks and gratitude to Professor A.R. Fowler for his critical reading, English polishing, and valuable comments that improved this contribution.

Funding information

The field work was supported by the Nuclear Materials Authority of Egypt (NMA), during the season 2014–2015.


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Copyright information

© Saudi Society for Geosciences 2018

Authors and Affiliations

  1. 1.Nuclear Materials Authority of EgyptCairoEgypt

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