Remote sensing techniques and geochemical constraints on the formation of the Wadi El-Hima mineralized granites, Egypt: new insights into the genesis and accumulation of garnets

Khedr, Mohamed Zaki; Khashaba, Saif M. Abo; El-Shibiny, N. H.; El-Arafy, Reda A.; Takazawa, Eiichi; Azer, Mokhles K.; Palin, Richard M.

doi:10.1007/s00531-022-02237-7

Cited by 16 publications

(42 citation statements)

References 82 publications

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“…This large area is affected by the Najd strike-slip shear-zone (NW-SE) and its related structure, such as the Nugrus thrust/or shear zone, trending in a NW-SE direction. This Najd shear zone (or the Nugrus shear zone) is not only controlling the distribution of beryl mineralization in the SED of Egypt, but also structurally controls the occurrence and accumulation of garnet mineralization, rare metalbearing granite, and gold concentrations of the Sukari gold mine; this is because this zone is considered a channels for hydrothermal fluids and alterations [93][94][95][96][97]. The Nugrus faults and shear zone (Figure 1b), with the NNW to NW-directed wrench corridor [87], may serve as conduits for the migration and circulation of hydrothermal fluid, which intensifies the hydrothermal alteration of granites and promotes mineral accumulation in a specific zone.…”

Section: Factors Controlling Beryl Distribution In the Sedmentioning

confidence: 99%

The Geology and Mineral Chemistry of Beryl Mineralization, South Eastern Desert, Egypt: A Deeper Insight into Genesis and Distribution

Khedr,

Saleh,

Abdelfadil

et al. 2024

Minerals

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Beryl mineralization in the Nugrus-Sikait domain in the South Eastern Desert (SED) of Egypt occurs as disseminated crystals in granitic pegmatite and quartz, as well as pegmatite veins crosscutting mélange schist and ophiolitic rocks. When granitic pegmatite comes into contact with the ophiolitic rocks, phlogopite and amphibole schists are formed due to K metasomatism. The ophiolitic mélange is intruded by leucogranite and related pegmatite along the NNW to NW Nugrus shear zone. Beryl samples have been collected from Um Sleimat, Madinat Nugrus, Wadi Abu Rusheid, and Wadi Sikait. Major oxides and in situ trace and rare earth elements (REEs) of beryl and associated minerals were analyzed through EPMA and LA-ICP-MS, respectively. The investigated beryl, based on its color and chemical compositions, can be classified into the two following types: pegmatitic beryl (type I) and schist-related beryl (type II). The former is colorless to pale green, and is mainly restricted in pegmatite veins; it is poor in Cr2O3 (up to 0.03 wt%) and MgO (Nil). The latter, deep green in color, is rich in Cr2O3 (up to 0.27 wt%) and MgO (up to 2.71 wt%), and occurs within quartz veins, phlogopite schists, and tremolite schists. The abundant beryl mineralization in phlogopite schists and their related quartz veins suggests that granite and associated pegmatite are the source rocks for the Be-bearing fluids that migrate along the NW-SE trending deep-seated tectonic zone, such as the Nugrus shear zone. Therefore, the formation of beryl in schists is attributed to the interaction of granitic/pegmatitic-derived Be-bearing fluids with serpentinite and gabbro interlayered with mélange schists. Variations in the trace and REE contents of both beryl types (I and II) indicate their two-stage formation from different compositions of Be-rich fluids, where light REEs, Zr, Nb, Ba, and Th decrease from type I beryl to type II. These two phases of beryl could be attributed to the magmatic/hydrothermal fluids associated with the pegmatite emplacement. The early phase of the late-stage magmatic-derived fluids was closely related to magma evolution and pegmatite formation, forming euhedral type I beryl. The late phase of pegmatite-derived fluids was mixed with serpentinite/schist-derived fluids that cause high V and Cr content in type II beryl. The composition of parent magmas of felsic rocks, the high degree of magma fractionation or the late stage melts, fluid compositions (rich in Be, Li, Cs, Rb, K), and alkali metasomatism, as well as the linear NW-SE trending deep-seated shear zone, are all factors possibly influencing beryl mineralization in the SED of Egypt.

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Section: Factors Controlling Beryl Distribution In the Sedmentioning

confidence: 99%

The Geology and Mineral Chemistry of Beryl Mineralization, South Eastern Desert, Egypt: A Deeper Insight into Genesis and Distribution

Khedr,

Saleh,

Abdelfadil

et al. 2024

Minerals

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“…820 Ma and 750 Ma [8,71], (2) the synorogenic alkaline and calc-alkaline granitoid suite characterizing the EAO compressional stage that extended from ca. 750 to 610 Ma [8,72,73], (3) the post-orogenic calc-alkaline and alkaline granitoid and dike swarm suites representing the EAO extensional phase that dominated from ca. 610 Ma and 535 Ma [8,72,74,75], and (4) the ophiolites and metamorphic complexes [72,75].…”

Section: Geologic Settingmentioning

confidence: 99%

Tectonic-Thermal Evolution of the Wadi El-Dahal Area, North Eastern Desert, Egypt: Constraints on the Suez Rift Development

Mansour,

Hasebe,

Khedr

et al. 2023

Minerals

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The Suez Rift developed as a northern extension of the Red Sea rift during the Oligocene-Miocene, whose flanks were constructed from the Neoproterozoic basement rocks of the Arabian–Nubian Shield. These basement rocks are comprised of the whole tectonic history since their formation. The Suez Rift initiation model and proposed thermal overprint role in the rifting process and flank development remain uncertain. Additionally, the amplitude of different regional tectonic events’ effects on the region is still debatable. Integration of fission-track thermochronology data with modeling of the time-temperature history has demonstrated efficiency in addressing such issues. In the context of this study, eleven representative samples were collected from the different rock units in the Wadi El-Dahal area at the northern tip of the western flank of the Suez Rift. These samples revealed Carboniferous zircon fission-track cooling ages of 353 ± 9 Ma and 344 ± 11 Ma. Meanwhile, the apatite fission-track analysis provided two spatially separated age groups: Permian-Triassic and Late Cretaceous, with average ages of 249 ± 11 Ma and ca. 86 ± 10 Ma, respectively. The time-temperature modeling revealed four possible cooling pulses representing exhumation events, which were initiated as a response to four tectonic activities: the accretion-subsequent event of erosion during the Neoproterozoic, the Hercynian (Variscan) tectonic event during the Devonian-Carboniferous, the Mid-Atlantic opening during the Cretaceous, and the Suez Rift opening during the Oligocene-Miocene. The western flank of the Suez Rift suggests a passive mechanical type with no extra thermal overprint, as indicated by the dominance of older thermochronological ages, modest rift flank elevations, and a reduction in the heat flow.

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“…The high Th/Ta ratio of the studied granitic rocks (217-459.5) suggests subduction-related magmatism rather than within-plate settings. According to [42,82], the examined volcanic and plutonic rocks exhibited a high LILE content compared to HFSE, indicating a continental arc context associated with subduction. The increase in Y contents, which further suggests an arc affinity and indicates that the parent magma was generated in an arc setting or partial melting of a rock produced within an arc, supports this arc setting.…”

Section: Tectonic Environment and Geodynamic Implicationmentioning

confidence: 99%

Au-Cu Resources in Some Mines from Antiquity in the South Gabal Um Monqul and Gabal Al Kharaza Prospects, North Eastern Desert, Egypt

Atef,

Surour,

Madani

et al. 2023

Geosciences

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Since Antiquity, sustainable resources of gold and copper have been mined at two prominent prospects in the north Eastern Desert of Egypt, namely the south Gabel Um Monqul (SGUM) and Gabal Al Kharaza (GKZ). Mineralization is hosted by Neoproterozoic shield rocks represented by dacite and monzo- to syenogranite at the SGUM prospect whereas they are diorite, granodiorite, and quartz feldspar porphyry at the GKZ prospect. These hosts have been emplaced in an island arc environment from calc-alkaline magmas with a peraluminous to metaluminous signature. They are hydrothermally altered including albitization, sericitization, silicification, epidotization, and chloritization. The Au and Cu mineralizations are confined to shear zones that lately filled with auriferous quartz veins adjacent to mineralized alteration zones. In the GKZ prospect, the old trenches trend mainly in a NW–SE direction whereas it is NE–SW and NW–SE in the SGUM prospect. Evidence of shearing ranges from megascopic conjugate fractures and shear planes in the outcrops to microscopic sheared and crumbled Au-Cu ore assemblages dominated by Fe-Cu sulfides, specularite, and barite. Microscopic investigation suggests that the formation of specularite is due to the shearing of early existing magnetite. The ore textures and paragenetic sequence indicate that pyrite in the alteration zones is oxidized, leading to the liberation of gold up to 3.3 g/t. The formulae of the analyzed electrum lie in the range Au74.5-76.8 Ag22.2-24.5. Integration of the field, geochemistry, and mineral chemistry data, combined with the gold fire assay data prove the presence of sustainable amounts of disseminated Au and Cu, not only in the mineralized quartz veins, but also in the alteration zones. Data materialized in our paper show similarities in the style of mineralization at the SGUM and the GKZ prospects with iron oxide-copper-gold (IOCG) deposits elsewhere in the Arabian-Nubian Shield (ANS) and other world examples.

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Remote sensing techniques and geochemical constraints on the formation of the Wadi El-Hima mineralized granites, Egypt: new insights into the genesis and accumulation of garnets

Cited by 16 publications

References 82 publications

The Geology and Mineral Chemistry of Beryl Mineralization, South Eastern Desert, Egypt: A Deeper Insight into Genesis and Distribution

The Geology and Mineral Chemistry of Beryl Mineralization, South Eastern Desert, Egypt: A Deeper Insight into Genesis and Distribution

Tectonic-Thermal Evolution of the Wadi El-Dahal Area, North Eastern Desert, Egypt: Constraints on the Suez Rift Development

Au-Cu Resources in Some Mines from Antiquity in the South Gabal Um Monqul and Gabal Al Kharaza Prospects, North Eastern Desert, Egypt

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