“…The majority of samples of the investigated quartz syenite, alkali feldspar syenite, trachyte, pyroclastic rocks and carbonatites have lower U concentration than that of the hypothetical distribution of uranium (Figs. 20d and 21d) and thus the mobilization awards mostly negative values (Cambon 1994;Saleh et al 2021), which in turn exhibit that uranium of these various investigated rock units is leaching out (migration).…”
Section: Uranium and Thorium Radioactivitymentioning
The geographic distribution of alkaline-carbonatitic complexes in the Egyptian Eastern Desert is restricted, leading to ongoing arguments on their geotectonic settings and petrogenesis. The petrogenesis of the El Mansouri Ring Complex has been investigated through the evaluation of the mineral chemistry and whole-rock geochemical data of alkaline and carbonatite rocks associated with this complex. The El Mansouri Ring Complex consists of trachyte, alkali feldspar syenite, and quartz syenites, along with carbonatites. Three types of carbonatites have been formed: a) calcite-carbonatite (søvites), b) dolomite-calcite carbonatite, and c) dolomite-carbonatite (beforsite). The alkaline rocks mostly include K-feldspar, plagioclase, sodic pyroxene (aegirine-augite), and alkali amphiboles (riebeckite and arfvedsonite), along with zircon, apatite, allanite, fluorite, and opaques. The El Mansouri intrusive rocks exhibit alkaline to peralkaline geochemical properties, characterized by low amounts of CaO, MgO, and Sr and significant concentrations of total alkalis (Na2O + K2O), Nb, Rb, Y, and REEs. These characteristics bear a resemblance to the properties seen in A-type granites that are formed from mantle-derived magma in an anorogenic setting. Their composition contains abundant rare earth elements (REEs) and incompatible elements, exhibiting negative anomalies in K, Sr, Ti, Ba, and P and positive anomalies in Zr and Rb. The carbonatites exhibit significant concentrations of high-field strength elements (HFSE), such as U, Th, Zr, Nb, and Y, as well as large ion lithophile elements (LILE), including Rb, Pb, and Sr. Additionally, they have negative anomalies of K, P, and Ti with regards to REEs. The El Mansouri alkaline rocks are plotted in the field of the within-plate granites and exhibit characteristics of the A1 subtype of the A-type granite. Additionally, the associated carbonatites are classified as calcio-carbonatites. The studied El Mansouri Ring Complex is proposed to have been formed by the fractional crystallization of a mafic magma comparable to oceanic island basalt (OIB). While the carbonatites originated from the crystal fractionation of a parental carbonated-syenitic magma. In the highly radioactive zone, the main minerals are kasolite, uranothorite, columbite, ishikawaite, xenotime, zircon, monazite, and fluorite. The carbonatites have the greatest U and Th. The radioactivity level in these carbonatites may reach up to 395 ppm eU, whereas the alkali feldspar syenite has 173 ppm eU and, and the quartz syenite contains 125 ppm eU.
“…The majority of samples of the investigated quartz syenite, alkali feldspar syenite, trachyte, pyroclastic rocks and carbonatites have lower U concentration than that of the hypothetical distribution of uranium (Figs. 20d and 21d) and thus the mobilization awards mostly negative values (Cambon 1994;Saleh et al 2021), which in turn exhibit that uranium of these various investigated rock units is leaching out (migration).…”
Section: Uranium and Thorium Radioactivitymentioning
The geographic distribution of alkaline-carbonatitic complexes in the Egyptian Eastern Desert is restricted, leading to ongoing arguments on their geotectonic settings and petrogenesis. The petrogenesis of the El Mansouri Ring Complex has been investigated through the evaluation of the mineral chemistry and whole-rock geochemical data of alkaline and carbonatite rocks associated with this complex. The El Mansouri Ring Complex consists of trachyte, alkali feldspar syenite, and quartz syenites, along with carbonatites. Three types of carbonatites have been formed: a) calcite-carbonatite (søvites), b) dolomite-calcite carbonatite, and c) dolomite-carbonatite (beforsite). The alkaline rocks mostly include K-feldspar, plagioclase, sodic pyroxene (aegirine-augite), and alkali amphiboles (riebeckite and arfvedsonite), along with zircon, apatite, allanite, fluorite, and opaques. The El Mansouri intrusive rocks exhibit alkaline to peralkaline geochemical properties, characterized by low amounts of CaO, MgO, and Sr and significant concentrations of total alkalis (Na2O + K2O), Nb, Rb, Y, and REEs. These characteristics bear a resemblance to the properties seen in A-type granites that are formed from mantle-derived magma in an anorogenic setting. Their composition contains abundant rare earth elements (REEs) and incompatible elements, exhibiting negative anomalies in K, Sr, Ti, Ba, and P and positive anomalies in Zr and Rb. The carbonatites exhibit significant concentrations of high-field strength elements (HFSE), such as U, Th, Zr, Nb, and Y, as well as large ion lithophile elements (LILE), including Rb, Pb, and Sr. Additionally, they have negative anomalies of K, P, and Ti with regards to REEs. The El Mansouri alkaline rocks are plotted in the field of the within-plate granites and exhibit characteristics of the A1 subtype of the A-type granite. Additionally, the associated carbonatites are classified as calcio-carbonatites. The studied El Mansouri Ring Complex is proposed to have been formed by the fractional crystallization of a mafic magma comparable to oceanic island basalt (OIB). While the carbonatites originated from the crystal fractionation of a parental carbonated-syenitic magma. In the highly radioactive zone, the main minerals are kasolite, uranothorite, columbite, ishikawaite, xenotime, zircon, monazite, and fluorite. The carbonatites have the greatest U and Th. The radioactivity level in these carbonatites may reach up to 395 ppm eU, whereas the alkali feldspar syenite has 173 ppm eU and, and the quartz syenite contains 125 ppm eU.
“…The alteration of trachyte was responsible for uranium enrichment, including albitisation, aegirinisation, chloritisation, and ferruginisation. These alterations are most probably related to the late magmatic deuteric and retrograde hydration processes (Hamdy et al 2017) and Saleh et al (2015; 2021). Figure 14 Radioactive elements plot for ground gamma-ray spectrometry measurements of the studied areas, SED, Egypt.…”
Section: Discussionmentioning
confidence: 99%
“…The Gabal Um Itly, G. El Beida, G. Um Domi and G. Um Doweila trachytic dykes suffered from more than one event of fluid-rock interaction such as, hydrothermal fluids, groundwater and meteoric water. The availability of meteoric water during the genesis of the secondary uranium minerals in the Eastern Desert was verified by Dawood et al (2003) and Saleh et al (2021Saleh et al ( , 2023.…”
Section: Spectrometric Prospectingmentioning
confidence: 94%
“…The composition of Palaeozoic and Mesozoic volcanic rocks ranges from olivine basalt to trachyte, whereas tertiary volcanic formations are mostly basaltic. There have been numerous prior research on these alkaline volcanic systems conducted by (Heikal 2003; Dawood et al 2003; Saleh et al 2004, 2007, 2015, 2020, 2021; Ibrahim et al 2005; Abdalla 2001; El Tohamy 2011; Gharib et al 2012; Nabawy and El Sharawy 2018; Sadek et al 2020; Sallam et al 2021; Abuamarah and Nabawy 2021; Kamar et al 2022; Oraby et al 2022; Ali-Bik et al 2022; Abdalla et al 2023; Dessouky and Ali 2018; Dessouky et al, 2023; Khaleal et al 2022, 2023).…”
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.
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