Occurrence of Samarskite-Y in the Mineralized Umm Lassifa Pegmatite, Central Eastern Desert, Egypt (original) (raw)
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Rare Metals Mineralization in Pegmatite at Abu Rusheid Area, South Eastern Desert, Egypt
International Journal of Mining Science, 2017
Two forms of pegmatite have been distinguished (segregations and dikes) hosted in the cataclastic rocks, at the Abu Rusheid area, southeastern Desert of Egypt. The cataclastic rocks covering an area about 2 km 2 , and composed of (from base to top); protomylonite, mylonite, ultramylonite, and quartzite with gradational contacts. The segregations are unzoned, flat lenses, less than 1 m, while the dikes, usually of the zoned type, have (2-15 m in length, and 0.3 m in width), trending NNW-SSE and dipping 10-30/ WSW parallel to banding of the cataclastic rocks. Albitization, chloritization, fluoritization and silicification are the major alteration processes in the cataclastics and pegmatites due to the effect of hydrothermal solution. The total REE content in the pegmatite ranges from 44 to 824 ppm with 342 ppm as the average. LREE is more enriched than the HREE in the pegmatite (LREE/HREE =7.8) and related to the presence of allanite-(Ce) and monazite-(Ce). Hydrothermal alteration during post-magmatic stages is shed light on the development of M-type tetrad effect in the REE pattern. The rare metals-bearing minerals such zircon, monazite-(Ce), allanite-(Ce), Nb-Ta minerals (columbite-(Fe) and euxenite-(Y), base metals (pyrite and molybdite), beryl and radioactive minerals (thorite, uranophane, torbernite and kasolite) have been found in the pegmatites. Isoconcentration maps show abnormal contents of Nb,Zr, Y, Pb, eU and eTh, and could be considered as low grade ores.
Geologija, 2011
The Abu Rushied area, situated in the South Eastern Desert of Egypt is a distinctive occurrence of economically important rare-metal mineralization where the host rocks are represented by granitic gneisses. Correspondingly, mineralogical and geochemical investigation of pegmatites pockets scattered within Abu Rusheid granitic gneisses revealed the presence of Hf-zircon, ferrocolumbite and uranyl silicate minerals (uranophane and kasolite). Electron microprobe analyses revealed the presence of Nb-Ta multioxide minerals (ishikawaite, uranopyrochlore, and fergusonite), uraninite, thorite and cassiterite as numerous inclusions in the recorded Hf-zircon and ferrocolumbite minerals.
Journal of Mineralogical and Petrological Sciences, 2010
An economically important raremetal mineralization is recorded in the pegmatite bodies of Gabal Ras Baroud younger granitic pluton, Central Eastern Desert of Egypt. These pegmatite bodies are of variable size and are compositionally zoned. Radiometric measurements of some anomalous pegmatite samples show that their equivalent uranium (eU) content is 219 -328 ppm, whereas their equivalent thorium (eTh) content is 783 -1101 ppm. On the other hand, the analysis of several separated mineral grains of some pegmatite samples using a scanning electron microscope and Xray diffraction revealed the presence of several economic minerals. These minerals include zircon, thorite, phlogopite mica, and columbite, in addition to the samarskite -Y mineral. Thorite was found as numerous inclusions of variable size and pattern in zircon. Electron microprobe analysis confirmed the presence of samarskite -Y whose composition corresponds to the empirical formula [(Y 0.49, REE 0.41, Th 0.06 , Si 0.05 , Ca 0.03, U 0.02 , Fe 0.01, Zr 0.00 ) Σ1.05 (Nb 0.75 , Ta 0.17 , Ti 0.01 ) Σ0.94 O 4 ]. Accordingly, the mineralized Ras Baroud pegmatite can be considered as a promising target ore for its raremetal mineralization that includes mainly Nb, Ta, Y, U, and REE together with Zr and Th.
Mineralogy of Mineralized Pegmatite of Ras Mohamed Granite , Southern Sinai , Egypt
2017
An economically important rare-metal mineralization is recorded in the mineralized pegmatite injected in alkali-feldspar microgranite of Gabal Samma at North Ras Mohammed granitic pluton, Southern Sinai, Egypt. The studied mineralization was found as distinguishable megascopic crystals scattered within the pegmatitic bodies of Gabal Samma granite and reach up to tens of centimeters. The mineralogy and geochemistry of the studied rare metal mineralization were determined using microscopic examination and X-ray Diffraction (XRD) as well as scanning electron microscope (SEM). These minerals include a unique occurrence of colored ishikawaite (uraniumrich samarskite) together with fergusonite-Y, allanite, titanite, zircon-thorite association, uranothorite and fluorite. The obtained SEM data for the studied minerals are showing the compositional limits of these minerals as specified in the literature. The occurrence of colored ishikawaite varieties (light brown, reddish dark brown and dar...
2021
Quartz-diorites, monzogranites and pegmatites are the main rock units in the studied area. The pegmatites occur as zoned pockets within monzogranites with zonal arrangement: border, wall, intermediate, and core zones. The wall zone have enrichment of radioactive and RREs-bearing minerals. K-feldspar, plagioclase and quartz are essential minerals, whereas uranothorite, columbite, zircon, xenotime, monazite, sphalerite and pyrite are accessories. Geochemically, the pegmatites of W. Ghadir have peraluminous character, ferroan with alkalic–calcic affinity and emplaced in within plate setting. These pegmatites revealed Li-bearing variety and high level of rare earth elements mineralization. The studied pegmatites exhibit high contents of Li, Nb, Cu, Ta, U, Th, Pb, Zr, Zn and Ga, can be from the previous data, the studied pegmatites can be classified as a Niobium–Yttrium–Fluorine (NYF) pegmatite or rare metal pegmatite. The trace elements ratio supports a low degree of fractionation and m...
Uncommonpresence of rare-metal mineralization is recorded in the mineralized pegmatite injectedin Wadi El Sheiholder granitoids at the central Eastern Desert of Egypt. The studied mineralization was found as distinguishable megascopic crystals of economic minerals scattered within the pegmatiticbodies. Detailed mineralogical and chemical investigation were carried out using microscopic examinations, x-ray diffraction (XRD),scanning electron microscope (SEM) providing with energy-dispersive spectrometer (EDS) and x-ray fluorescence (XRF). These studiesrevealed the presence of several valuable minerals such aseuxenite-(Y), fergusonite-(Y), allanite-(Ce) and xenotime-(Y), in addition touranothorite and zircon.Accordingly, the mineralized Wadi El Sheih pegmatite can be considered as a promising target ore for its rare metal mineralization that includes mainly Nb, Ta, Y, U, Thand REE together with Zr and Hf.
Arabian Journal of Geosciences, 2020
Granitic pegmatites of Wadi Al-Baroud area in the Central Eastern Desert of Egypt have appreciated amounts of radioactive (U, Th) and rare metal-(Nb, Ta, Y, Zr, Hf, and rare earth elements-REEs) bearing minerals. A combination of both geochemical and physical methods has been used for investigation of Wadi Al-Baroud granitic pegmatites. The identification, imaging, and chemistry of rare metal-bearing minerals were conducted using the optical microscope, X-ray diffraction (XRD), scanning electron microscope (SEM), and electron microprobe analyzer (EMPA). The pegmatites host Nb-Ta oxides (euxenite-Y, fergusonite-Y, and yttrocolumbite-Y), REE minerals (xenotime-Y, monazite-Ce and allanite-Ce), U-Th minerals (thorite and uranothorite), and Hf-rich zircon. In addition, muscovite, quartz, feldspars, and some iron oxide minerals such as magnetite, goethite, and lepidocrocite represent the essential, gangue, and associated minerals. Physical upgrading of Wadi Al-Baroudmineralized pegmatites was carried out using gravity and magnetic separation techniques. Applying the optimum conditions for both separation techniques, it is possible to attain a good concentrate with an acceptable recovery. Accordingly, the final concentrate contains~0.25% U, 0.46% Th, and 0.31% REE with recovery of 91.17% U, 96.56% Th, and 86.19% REE in a weight of 6.58% out of the original sample assays 0.02% U, 0.04% Th, and 0.03% REE. Therefore, it is well-recommended that the final concentrate should subject to proper hydrometallurgical treatment to extract their valuable metal contents.
2020
The main rock units exposed in Kab Amiri area are chronologically arranged as follows; Dismembered ophiolitic rocks that are represented by serpentinites and talccarbonates rocks and metabasalts, Island arc assemblage are represented by metasediments and metavolcanics rocks, granitoid rocks include syn orogenic granites, late orogenic granites and episyenite, dikes (aplitic and basaltic), pegmatite and stream sediments. Mineralogical investigations show the presence of fergusonite and columbite as Nb-Ta mineral group, uraninite, thorite, uranothorite and zircon thorite intergrowth as radioactive minerals, zircon, fluorite and allanite as radioREEs bearing minerals, Field and petrological Pravrach regulation and coordination studies demonstrate that the main alteration features in the studied rocks are hematitization, sericitization, saussuritization, kaolinitization, albitization, chloritization, silicification, and muscovitization. Highly altered granite was confirmed from the unus...
A unique occurrence of a samarskite–Y variety was recorded in the stream sediments surrounding the Ras Baroud younger granite pluton, Cenral Eastern Desert of Egypt. This mineral variety was found associated with columbite, zircon, magnetite, garnet, goethite, ilmenite, hematite and mica. In the representative composite sample of these sediments, samarskite–Y was found to assay 1.5% by weight. Both microscopic examination and Scanning Electron Microscope (SEM) were used to identify and describe the studied mineral variety, while the electron microprobe analysis was applied to determine its empirical formula. Size analysis of the representative samarskite-Y stream sample revealed its wide distribution in almost all size fractions with an increased tendency to concentrate in the small sizes. The investigated mineral variety is moderately paramagnetic and its magnetic susceptibility is lower than that of the associated columbite. Accordingly, it would be possible to obtain a rich samarskite concentrate using both gravity and magnetic separation techniques.
2021
Article history: Received 1 April 2021 Received in revised form 15 April 2021 Accepted 15 April 2021 Available online 17 April 2021 Rare-metals and rare earth mineralization has been observed in Wadi El Sheih older granitoids bearing uncommon mineralized pegmatite. This type of mineralization was recorded as distinguishable mega-crystals scattered within the pegmatite. Detailed mineralogical investigation was carried out using different analytical techniques as: microscopic examinations, x-ray diffraction (XRD), and scanning electron microscope (SEM) providing with energy dispersive spectrometer (EDS) unite. These studies revealed the presence of several valuable minerals like Euxenite and Fergusonite as well as; gives a clear comparative idea on the mineralogical and geochemical characteristics of the Nb-Ta oxides.