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![The Arabian Nubian Shield (ANS), [14] North Eastern Desert (NED), Central Eastern Desert (CED), and Southern Eastern Desert (SED).](publication/362727271/figure/fig1/AS:11431281079501819@1660717968841/The-Arabian-Nubian-Shield-ANS-14-North-Eastern-Desert-NED-Central-Eastern-Desert.png)
The Arabian Nubian Shield (ANS), [14] North Eastern Desert (NED), Central Eastern Desert (CED), and Southern Eastern Desert (SED).
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![Figure 1. The Arabian Nubian Shield (ANS), [14] North Eastern Desert...](publication/362727271/figure/fig1/AS:11431281079501819@1660717968841/The-Arabian-Nubian-Shield-ANS-14-North-Eastern-Desert-NED-Central-Eastern-Desert_Q320.jpg)
The present study was carried out on promising lamprophyre dykes at Wadi Sikait, through the mineralogical and petrography studies with emphasis on the radiological hazard’s indices along Wadi Sikait. So, the radioelement contents in the studied rocks were measured radiometrically by using gamma-spectrometry (NaI-detector). The psammitic gneisses f...
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... is a REEs phosphate mineral that contains around 70% REE oxides and is structurally similar to huttonite (ThSiO4), cheralite (CaTh (PO4) 33, 31, 34, 29]. The BSE imaging and EDX analysis of cheralite grains (figure 5d and 5e) revealed that cheralite grains are primarily made up of P (9-6 wt%), Th+U (50-40 International Conference on Chemical and Environmental Engineering (ICEE-11) Journal of Physics: Conference Series 2305 (2022) 012001 ...
Context 2
... be entrapped and precipitated along the dyke fractures, or as a geochemical barrier, causing a local reduction zone that aids in uranium precept. Because of its geochemical behavior and the composition of its host rocks, uranium is the most likely element to be mobilized. For granitic rocks, the most typically documented eU/eTh ratio is around 0. 33. [39, 38, 40, 41]. This ratio is used as a radiometric indicator to determine the destiny of the U-mineralization and its vicinity. However, an increase in this ratio beyond 0.33 could imply uranium enrichment, whilst a decrease in this ratio below 0.33 could indicate depleted or initially uranium-poor granites. In most productive uraniferous rocks, the ...
Citations
... The study area lies between latitudes 24 o 38′ 36〃to 24 o 39 / 21〃N and longitudes 34 o 47′ 03〃 to 34 o 48′ 06〃E (Fig. 2). The tectono-stratigraphic sequence begins from the oldest as follows; psammitic gneiss, ophiolitic mélange, monzogranites, and lamprophyre dykes [8]. psammitic gneiss striking NNE-SSW contacted elongate with the ophiolitic mélange from the eastern side and the monzogranites from the other western part. ...
... Geological map of W. Sikait, SED, Egypt[8]. ...
... ) banding in the gneisses with dipping 65° toward NW direction[8]. b) Shearing and hematitization of the psammitic gneiss. ...
... The previous works on the W. Sikait area are numerous (e.g., Ibrahim and Ragab, 2011;Ibrahim, 2013, El Tohamy, 2019and Kamar et al., 2022. The type of W. Sikait lamprophyres was not achieved. ...
... (El-Balakssy et al., 2012. Kamar et al., (2022) recorded the alteration of monazite to cheralite in the study area. The BSE image and EDX spectrum of Sikait lamprophyre samples illustrate the relation between monazite and allanite as shown in figure 4. , the name is derived from its yttrium content and similarity to columbite. ...
... Th- (64) (14) Zr (80), Hf (2), Si (7) Anhedral crystal on quartz surfaces *Minerals recorded by Kamar et al. (2022) Appl. Sci., 13(2): 233-256, 2023EISSN: 2706-7947 ISSN: 2077-4613 DOI: 10.36632/mejas/2023 ...
The lamprophyre dykes extruded in the psammitic gneisses, ophiolitic mélange, and monzogranites at Wadi Sikait provinces. Microscopic investigation of the lamprophyres indicates that they are mostly composed of spessartites and kersantite. The microscopic and ESEM investigations on the accessory minerals revealed the presence of monazite-allanite, yttrocolumbite, gold, cassiterite, wolframite, galena, and native nickel. Geochemically, the lamprophyres are basalt and basanite/tephrite in composition with calc-alkaline characters. They are enriched in TiO 2 , Fe 2 O 3 , MnO, CaO, Na 2 O, P 2 O 5 , V, Zn, Li, Nb, Ta, Th, Zr, and U however depleted in SiO2, Al2O3, MgO, K2O, Cr, Co as well as Ni relative to the corresponding rock types. The high LILE contents, Nb and Ta relative to Hf, depletion in HREEs, along with elevated Ba/Nb and Ba/La ratio illustrate an enriched mantle source. The enrichment of LREEs in the lamprophyre dykes indicates a low degree of partial melting. High Ba and U values implies the addition of Ba and U to the protolith via metasomatism or hydrothermal fluids in the source region. The peculiar M-W type tetrad effect confirms the effect of the water-rich phase and could be an indication of Au mineralization, as indicated by the presence of gold grains in the separated heavy fraction.
The investigated Phanerozoic volcanic (Gabal Um Itly, G. El Beida, G. Um Domi and G. Um Doweila) areas in the south Eastern Desert of Egypt of the Northern Arabian-Nubian Shield (ANS), have been a peralkaline affinity and display a continuous composition trachyte rocks. Geochemically, the studied rocks show significant negative anomalies in Ba, Sr, and Ti on the primitive mantle normalized trace element plot, indicating an ancestry involving plagioclase and Fe-Ti oxide fractionation. The concentrations of uranium mineralization and rare earth elements in the trachyte rocks is related to the presence of uranophane, kasolite, umohoite, autunite, monazite and allanite. The distribution of uranium, thorium and their ratios in the trachyte rocks reflects a direct strong relation, which suggests that U distribution is, at least in part, governed primarily by magmatic processes and disturbed later by a hydrothermal solution.
