Abu Rusheid Area Research Articles

Mineral chemistry of monazite-(Nd), xenotime-(Y), apatite, fluorite and zircon hosting in lamprophyre dyke in Abu Rusheid area, South Eastern Desert, Egypt

The studied mineralized lamprophyre dyke in Abu Rusheid area is trending NNW-SSE, and occurs within Abu Rusheid mineralized shear zone, measuring 0.2 - 1.0 m in width and 0.5 - 1.0 km in length. It was emplaced parallel with the Abu Rusheid shear zone. The dyke is mainly composed of plagioclases, amphiboles, mica (muscovite and biotite), relics of pyroxenes with K-feldspars and quartz derived from surrounding country rocks as phenocrysts embedded in fine-grained groundmass. The lamprophyre dyke hosts REE-minerals monazite-(Nd), xenotime-(Y), and REE-bearing minerals apatite, fluorite, zircon-(Hf), rutile with inclusions of xenotime and iron oxides. The emplacement of lamprophyre dyke caused heating in the mineralized shear zone of Abu Rusheid area. The lamprophyre dyke was subsequently affected by hydrothermal alterations (e.g. chlorite-carbonate, muscovitization, fluoritization). The REE were remobilized from the mineralized shear zones by hydrothermal solutions and re-precipitated as REE-minerals xenotime-(Y) and monazite-(Nd) around flourapatite, fluorite, zircon and rutile. The solid solutions between monazite-(Nd) and xenotime-(Y) were formed as a product precipitation from hydrothermal solutions. Also, the apatite mineral in the lamprophyre dyke was subjected to the heating during the emplacement, which lead to its alteration and breakdown with concominant precipitation of xenotime-(Y) and monazite-(Nd). The chemistry of monazite-(Nd) and xenotime-(Y) obtained by scanning electron microscopy (SEM), and electron probe microanalysis (EPMA), showed that these minerals are enriched in U and Th. The monazite-(Nd) associated with fluorapatite in the studied dyke is poor in Th (0.02 ≤ Th ≤ 0.81 wt%), but usually rich in U (0.92 ≤ U ≤ 2.91 wt%), which indicates that monazite formed as a result of flourapatite metasomatism.

Recovery of some valuable elements from lamprophyre dykes in the Abu Rusheid area, Southeastern Desert, Egypt

In the Abu Rusheid area, Southeastern Desert of Egypt, polymineralized (HREEs, U, Zn and Pb) lamprophyre dykes are recently recorded. The lamprophyre dykes cut cataclastic rocks along share zones in NNW-SSE trends. The secondary U-minerals are essentially represented by uranophane, kasolite, torbernite and autunite. Experimental work was carried out on the lamprophyre dykes for the recovery of uranium and other valuable elements (e.g. Zn, Pb and Al) from 50 kg of technological sample. The optimum conditions were: 100 g/L sulfuric acid concentration, 1:5 S/L (solid/liquid) and soaking for 15 days at room temperature. The leaching efficiencies for the recovery of uranium and other elements like Al, Zn and Pb were 40, 33.6, 98.8 and 78, respectively.

Geochemistry and Radioactivity of Mineralized Pegmatite from Abu Rusheid Area, South Eastern Desert, Egypt

The mineralized pegmatite of Abu-Rusheid area, S. Eastern Desert, has quartz core and feldspars and mica margins. This pegamtite was analyzed by the Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) to determine the content of the major and trace elements including the rare earth elements (REE). The mineralized pegmatite vein trends NNW-SSE with dip of about 10- 30° due WSW. It is emplaced parallel to foliation and banding of the cataclastic country rocks. The studied pegmatite is classified as rare metals-enriched and shows a zonal distribution from the barren core to the mineralized wall-zone in the metals; Nb, Ta, Zr, Hf, Th, U, Y and Ga. The main carriers of the trace metals are zircon, rutile, columbitetantalite, samarskite and other REE and Th-U minerals. Cassiterite, chlorite, deep violet fluorite, calcite, goethite, hematite, pyrite, magnetite, zinnwaldite, and phlogobite, are the main accessory minerals. The studied pegmatite is highly differentiated, NYF-type and characterized by high FeO/MgO ratio with high concentration of Nb, Y, Zr, Th, U, REE (except Eu), and Ga. It is derived from Fenriched proterozoic crustal source depleted in Cs, B and P. The rock is peraluminous and highly fractionated and had been affected by hydrothermal alteration. The pegmatite displays clear M-type tetrad effect of the REE. The calculated tetrad effect in the pegmatite of Abu-Rusheid demonstrates clear tendency towards the ratios of the common isovalents such as Zr/Hf, Nb/Ta and Y/Ho. However, the tetrad effect seems not to be mutual with the content of Na2O and Rb/Sr. The absence of coherence between tetrad effect and soda content may indicate insignificant role of the Na-metasomatism in developing the tetrad effect. The pegmatite has a prominent negative Eu anomaly and excessively low K/Rb ratio. The radioactivity of the studied pegmatite is related to a) uranium mineral (autunite), b) thorium minerals (thorite, thorianite and uranothorite) and c)

Mineral Chemistry and Genesis of Uranyl Minerals Associated with Psammitic Gneisses, Abu Rusheid Area, South Eastern Desert of Egypt

Mineral Chemistry and Genesis of Uranyl Minerals Associated with Psammitic Gneisses, Abu Rusheid Area, South Eastern Desert of Egypt

Horizontal Loop Electromagnetic and Self-Potential Signatures of Mineralized Structures: A Case Study from Abu Rusheid Area, Southeastern Desert, Egypt

Horizontal Loop Electromagnetic and Self-Potential Signatures of Mineralized Structures: A Case Study from Abu Rusheid Area, Southeastern Desert, Egypt