Magmatic and post-magmatic evolution of post-collisional rare-metal bearing granite: The Neoproterozoic Homrit Akarem Granitic Intrusion, south Eastern Desert of Egypt, Arabian-Nubian Shield

Abuamarah, Bassam A.; Azer, Mokhles K.; Seddik, Amany M.A.; Asimow, Paul D.; Guzman, Pedro; Fultz, B.; Wilner, Madeleine; Dalleska, Nathan F.; Darwish, Mahmoud H.

doi:10.1016/j.chemer.2021.125840

Cited by 22 publications

(10 citation statements)

References 107 publications

(127 reference statements)

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“…Accordingly, several studies reveal different petrogenesis of Egyptian granitic rocks, varying from syn-late-orogenic to post-orogenic as well as anorogenic granites. Among different granitic rocks, the post-orogenic and anorogenic granites have conspicuous rare metals enrichment that are commonly modified by later hydrothermal processes such as albitization, silicification, and fluoritization [9][10][11][12][13]. This rare metal mineralization includes Zr, Ta, Nb, and W as well as others, such as high contents of rare earth element (REE), U, and Th mineralization, attracting the attention of many geologists and authors to shed light on theses rocks, due to their importance in industrial applications [14].…”

Section: Introductionmentioning

confidence: 99%

Radiological Hazards and Natural Radionuclide Distribution in Granitic Rocks of Homrit Waggat Area, Central Eastern Desert, Egypt

et al. 2022

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Natural radioactivity, radiological hazard, and petrological studies of Homrit Waggat granitic rocks, Central Eastern Desert, Egypt were performed in order to assess their suitability as ornamental stone. On the basis of mineralogical and geochemical compositions, Homrit Waggat granitic rocks can be subdivided into two subclasses. The first class comprises granodiorite and tonalite (I-type) and is ascribed to volcanic arc, whereas the second one includes alkali-feldspar granite, syenogranite, and albitized granite with high-K calc alkaline character, which is related to post-orogenic granites. 238U, 226Ra, 232Th, and 40K activities of natural radionuclides occurring in the examined rocks were measured radiometrically using sodium iodide detector. Furthermore, assessment of the hazard indices—such as: annual effective dose (AED) with mean values (0.11, 0.09, 0.07, 0.05, and 0.03, standard value = 0.07); gamma radiation index (Iγ) with mean values (0.6, 0.5, 0.4, 0.3, and 0.14, standard value = 0.5); internal (Hin) with mean values (0.6, 0.5, 0.4, 0.3, and 0.2, standard value = 1.0); external (Hex) index (0.5, 0.4, 0.3, 0.24, and 0.12, standard value = 1.0); absorbed gamma dose rate (D) with mean values (86.4, 75.9, 53.5, 43.6, and 20.8, standard value = 57); and radium equivalent activity (Raeq) with mean values (180, 154, 106.6, 90.1, and 42.7, standard value = 370)—were evaluated with the knowledge of the natural radionuclides. The result of these indices falls within the acceptable worldwide limits. Therefore, we suggest that these rocks are safe to be used in industrial applications.

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Section: Introductionmentioning

confidence: 99%

Radiological Hazards and Natural Radionuclide Distribution in Granitic Rocks of Homrit Waggat Area, Central Eastern Desert, Egypt

et al. 2022

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“…Various petrogenetic models have been proposed to explain the formation of A-type rocks in general [55] and in the ANS in particular [56][57][58]. However, no single model adequately explains the wide range of chemical compositions observed among these granitic rocks.…”

Section: Petrogenesis Of Mount El-sibai Granitesmentioning

confidence: 99%

Magmatic Evolution and Rare Metal Mineralization in Mount El-Sibai Peralkaline Granites, Central Eastern Desert, Egypt: Insights from Whole-Rock Geochemistry and Mineral Chemistry Data

et al. 2023

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The Ediacaran peralkaline granites, which were emplaced during the post-collisional tectonic extensional stage, have a limited occurrence in the northern tip of the Nubian Shield. In this contribution, we present new mineralogical and geochemical data of Mount El-Sibai granites from the Central Eastern Desert of Egypt. The aim is to discuss their crystallization condition, tectonic setting, and petrogenesis as well as the magmatic evolution of their associated mineralization. Mount El-Sibai consists of alkali-feldspar granites (AFGs) as a main rock unit with scattered and small occurrences of alkali-amphibole granites (AAGs) at the periphery. The AAG contain columbite, nioboaeschynite, zircon and thorite as important rare metal-bearing minerals. Geochemically, both of AFG and AAG exhibit a highly evolved nature with a typical peralkaline composition (A/CNK = 0.82–0.97) and formed in within-plate anorogenic setting associated with crustal extension and/or rifting. They are enriched in some LILEs (Rb, K, and Th) and HFSEs (Ta, Pb, Zr, and Y), but strongly depleted in Ba, Sr, P and Ti with pronounced negative Eu anomalies (Eu/Eu* = 0.07–0.34), consistent with an A-type granite geochemical signature. The calculated TZrn (774–878 °C) temperatures indicate that the magma was significantly hot, promoting the saturation of zircon. The texture and chemistry of minerals suggest that they were crystallized directly from a granitic magma and were later subject to late- to post-magmatic fluids. Both granitic types were most likely generated through partial melting of a juvenile crustal source followed by magmatic fractionation. The lithospheric delamination is the main mechanism which causes uplifting of the asthenospheric melts and hence provides enough heat for crustal melting. The produced parent magma was subjected to prolonged fractional crystallization to produce the different types of Mount El-Sibai granites at different shallow crustal levels. During magma fractionation, the post-magmatic fluids (especially fluorine) contribute significantly to the formation of rare metal mineralization within Mount El-Sibai granites.

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“…Granitoid of variable sizes, shapes, chemical compositions, colors, and ages are abundant in south Sinai and the northern (in particular), central, and southern parts of the Egyptian Eastern Desert (e.g., Azer et al, 2020;Abdel-Karim et al, 2021;Saleh et al, 2022a;Khaleal et al, 2023a;Khaleal et al, 2023b). They have grey, pink, and white (leucogranites) colors and range from calc alkaline (syncollision) to alkaline (post-collision) as well as from metaluminous to strongly peraluminous in composition (Gharib, 2012;Abuamarah et al, 2022;. Notably, they are abundant, straddle about sixty percent of the total crystalline rocks in Egypt, and have high economic significance due to their high durability and aesthetic appearance (Alzahrani et al, 2022;Lasheen et al, 2023).…”

Section: Introductionmentioning

confidence: 99%

Physico-mechanical properties and shielding efficiency in relation to mineralogical and geochemical compositions of Um Had granitoid, Central Eastern Desert, Egypt

Rashwan,

Lasheen,

Abdelwahab

et al. 2023

Front. Earth Sci.

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The current work aims to describe the physico-mechanical characteristics and shielding efficiency with reference to the mineralogical and geochemical compositions of the Neoproterozoic Um Had composite granitoid pluton in order to deduce their favorability as dimension stones. The Um Had granitoid pluton has an elliptical outline with a mean diameter of about 10 km. This pluton is a composite (ranging from white to reddish pink color), hard, massive, and medium- to coarse-grained granitoid body. It is classified as syenogranite according to their modal and bulk chemical compositions. Geochemically, the granitoid pluton is a highly calc-alkaline, peraluminous granite, formed by low degree partial melting of tonalitic source rock in a post-collisional tectonic setting. The physico-mechanical properties of the granitoid pluton under study satisfy the requirements of dimension stone in terms of their bulk density (from 2561 to 2564 kg/m3), and to some extent water absorption capacity (from 0.38% to 0.55%). However, their compressive strength values (50.4–113.4 MPa) do not achieve the minimum requirement for interior use and light duty exterior use. This study delves into the potential of some of our syenogranite samples (I, IIA, IIS, and 10) as gamma radiation shielding materials. We have assessed the mass attenuation coefficient (GMAC), effective atomic number (Zeff), exposure build-up factor (EBF), and energy absorption build-up factor (EABF) for each of these samples. The GMAC and Zeff calculations were performed using the Phy-X online software, across a photon energy range of 0.015–15 MeV. Our findings suggest an inverse relationship between photon energy and GMAC, with the highest values observed for the (I) granite sample (∼18). This study shows the promising radiation shielding capacity of our samples. The insights derived from GMAC, Zeff, EBF, and EABF can serve as a guide for the development of effective, naturally sourced radiation shielding materials.

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Magmatic and post-magmatic evolution of post-collisional rare-metal bearing granite: The Neoproterozoic Homrit Akarem Granitic Intrusion, south Eastern Desert of Egypt, Arabian-Nubian Shield

Cited by 22 publications

References 107 publications

Radiological Hazards and Natural Radionuclide Distribution in Granitic Rocks of Homrit Waggat Area, Central Eastern Desert, Egypt

Radiological Hazards and Natural Radionuclide Distribution in Granitic Rocks of Homrit Waggat Area, Central Eastern Desert, Egypt

Magmatic Evolution and Rare Metal Mineralization in Mount El-Sibai Peralkaline Granites, Central Eastern Desert, Egypt: Insights from Whole-Rock Geochemistry and Mineral Chemistry Data

Physico-mechanical properties and shielding efficiency in relation to mineralogical and geochemical compositions of Um Had granitoid, Central Eastern Desert, Egypt

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