Mineralization styles, alteration mineralogy, and sulfur isotope geochemistry of volcanogenic massive sulfide deposits in the Shadli Metavolcanics Belt, South Eastern Desert, Egypt: Metallogenic implications

Faisal, Mohamed; Yang, Xiaoyong; Zhang, Huishan; Amuda, Abdulgafar Kayode; Sun, Chenguang; Mustafa, Sara; Gul, Muhammad A.

doi:10.1016/j.oregeorev.2021.104402

Cited by 6 publications

(2 citation statements)

References 77 publications

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“…The precipitation of iron ores may be found close to or distal from the high-temperature up-flow zone of VMS-related submarine magmatic-hydrothermal activity (Peter et al, 2014). Locally, the iron successions in the Egyptian Eastern Desert have been linked to volcanic eruptions and are proposed to originate in an intra-back-arc basin setting (Faisal et al, 2022).…”

Section: Depositional Environmentmentioning

confidence: 99%

Unravelling the genesis and depositional setting of Neoproterozoic banded iron formation from central Eastern Desert, Egypt

Sami,

Faisal,

Leybourne

et al. 2024

Front. Earth Sci.

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The Neoproterozoic banded iron formations (BIFs) are widely occurred in the Egyptian Eastern Desert. This study integrates field observations, petrographic studies, geochemical data, and lead isotopes to construct the genesis and depositional environment of Wadi El-Mis hama BIF deposits. The iron layers, primarily of oxide facies within a volcano-sedimentary sequence, comprise magnetite-rich beds alternating with jaspilite or silicate laminae. The studied BIFs exhibit a dominant composition of SiO2 and Fe2O3t with relatively low contents of TiO2 and Al2O3. The positive correlation of REEs (La, Sm, Yb) with Zr and low concentrations of HFSEs (Ta, Nb, Th, Hf) indicate a primary formation mechanism of chemical precipitation, maintaining original geochemical signatures. Geochemical patterns show depletion in LREEs, enrichment in HREEs (La/YbPAAS = 0.08–0.12), and positive La anomalies (La/LaPAAS = 1.15–8.57), consistent with seawater influence. Additionally, various geochemical discrimination diagrams supported by elevated super-chondritic Y/Ho values (29.6–38.7), weak positive Eu anomalies, and low contents of transition metals (Cu and Zn), point to the interaction of low-temperature (<200°C) hydrothermal fluids (bearing Fe and Si) with seawater during the deposition of the BIFs. The lack of significant negative Ce anomalies along with low Ni/Co, U/Th, and Cu/Zn ratios, imply that the iron mineralization was precipitated from dysoxic to oxic conditions. The geochemical and Pb isotopic data suggest that the iron deposits formed in an extensional geodynamic setting (intra-oceanic arc basin environment) due to the subduction of the Mozambique Plate, with signatures closely matching other Precambrian Algoma-type BIFs.

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Section: Depositional Environmentmentioning

confidence: 99%

Unravelling the genesis and depositional setting of Neoproterozoic banded iron formation from central Eastern Desert, Egypt

Sami,

Faisal,

Leybourne

et al. 2024

Front. Earth Sci.

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“…The juvenile crust of the ANS was formed during the Neoproterozoic Era through a pre-collisional stage characterized by island-arc volcanism [8]. The collisional stage ended between 615 and 600 Ma, followed by orogenic collapse within the period 595-575 Ma, and subsequent transpressional tectonism along significant shear zones [18][19][20]. After the cessation of the Pan-African orogenic compressive tectonic activity around 550 Ma, an extended phase of anorogenic alkaline complexes intruded over almost the entire Phanerozoic Era until the opening of the Red Sea about 23 Ma ago [3,21].…”

Section: Geologic Settingmentioning

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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Metallic Ores in North Africa: New Results and Achievements in the Post-2016 Era

Surour

2024

Regional Geology Reviews

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Mineralization styles, alteration mineralogy, and sulfur isotope geochemistry of volcanogenic massive sulfide deposits in the Shadli Metavolcanics Belt, South Eastern Desert, Egypt: Metallogenic implications

Cited by 6 publications

References 77 publications

Unravelling the genesis and depositional setting of Neoproterozoic banded iron formation from central Eastern Desert, Egypt

Unravelling the genesis and depositional setting of Neoproterozoic banded iron formation from 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

Metallic Ores in North Africa: New Results and Achievements in the Post-2016 Era

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