The calc-alkaline, gneissic El Shalul granite is the westernmost gneiss dome or core complex within the Arabian–Nubian Shield. Previous studies have indicated that it represents either a window into the underlying pre-Neoproterozoic Sahara metacraton or a melt derived from the metacraton. U–Pb LA-ICP-MS dating of magmatic zircons from two samples of the variably foliated El Shalul pluton gives ages of 637 ± 5 Ma and 630 ± 6 Ma, excluding it from representing exhumed cratonic rocks. The ages are, however, indistinguishable from the age of the Um Ba'anib pluton, constituting the core of the Meatiq Gneiss Dome, as well as several other plutons in the Eastern Desert, indicating an important magmatic pulse in the Arabian–Nubian Shield in Late Cryogenian time. Major and trace element data indicate a within-plate setting. Bulk rock Nd-isotope and Hf-isotope data on zircons from the El Shalul pluton indicate derivation of the primary melt from a relatively juvenile source, either the lower crust of a mid-Neoproterozoic volcanic arc or as a result of fractionation of a mantle-derived mafic melt. Sm–Nd bulk rock isotopic data indicate a model age of c. 720 Ma for the protolith from which the melt was derived. Time-corrected Hf-isotope data obtained on the magmatic zircons indicate that the bulk of the source rock was extracted from the mantle around 810 Ma.

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The equilibrium and kinetic characteristics of rare earths adsorption process using the strong acid macro reticular resin Dowex 50X8 from El-Erediya chloride liqueurs have been determined. The adsorption parameters including pH, contact time, temperature, resin to aqueous ratio and rare earths initial concentration in aqueous have been optimized. The practical adsorption capacity of rare earths upon the resin under the optimum conditions has been found to attain 80 mg/g which matches with Langmuir theoretical capacity. The physical parameters including the adsorption kinetics, the isotherm models and the thermodynamic data have also been determined. The adsorption process has been found to agree with both the pseudo second order reaction, the Langmuir isotherm and confirms with the concept of the matrix diffusion controls. A successful preconcentration process for the rare earths content was done with a preconcentration factor of about 42.33. Considerable rare earths cake was precipitated from the chloride eluate solutions using oxalic acid.

An economically important rare -metal 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 X -ray 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

horizon and the footwall-altered rocks enclose historical trenches and pits. Sulfide-rich core samples are enriched in Zn, relative to Cu, and in Ag, which indicates the low-temperature nature of the hydrothermal system. The prospect was affected by supergene processes, which led to the widespread occurrence of secondary copper minerals and gold enrichment relative to the leached base metals, especially Zn. The prospect formed through a limited rifting of an intraoceanic island arc which resulted in the formation of a smallscale volcanogenic Zn-Cu-Ag-Au prospect.