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Petrology, geochemistry, radioactivity, and m–W type rare earth element tetrads of el Sela altered granites, south eastern desert,Egypt

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Acta Geochimica 2019年第1期38卷 95-119页

作者： a.m.el mezayen m.A.Heikal m.G.el-Feky H.A.Shahin I.K.Abu Zeid S.R.Lasheen Geology Department Faculty of Science Al Azhar University Nuclear material Authority

The southern part of the Eastern Desert of Egypt—about 30 km southwest of Abu-Ramad city—is mainly covered by ophiolitic rocks(Sul Hamed), island arc assemblage, younger granites(muscovite granites of Qash Amer and two mica granites of el Sela), and various acidic and basic dikes. Field, petrological, and geochemical studies indicate that the el Sela shear zone has been subject to hydrothermal and supergene alteration such as kaolinization, albitization, sericitization, and hematitization. It is invaded by quartz ENE–WSW veins associated with hydrothermal alteration accompanied by radioactive mineralization. The investigated younger granitic rocks had very low contents of compatible elements, such as Cr, Ni,and Co; and high contents of incompatible elements, such as Zr, and large ion lithophiles, such as Sr, especially in the el Sela shear zone. major oxide and trace element analyses revealed calc-alkaline affinity and peraluminous *** highly differentiated granitic rocks' lower Zr/Hf and higher Y/Ho than the normal ratio are consistent with hydrothermal alteration. most samples had rare earth element(REE)-patterns with an m-type tetrad effect in the first and fourth segments and a W-type tetrad in the third segment. The average ∑REE in the studied granites was lower than the world granite average; the ratio of light to heavy REEs greater. The main radioactive, uranium-bearing, and uraniferous Fe and mn minerals are uranothorite,autunite, uranophane and autunite as compounds, kasolite,columbite, xenotime, uranophane-bearing zircon and jarosite, silver-bearing pyrite, hematite, and autunite-bearing pyrolusite.

关键词： Geochemistry REE-tetrad effect Radioactive minerals Radiometric measurements Qash Amer el Sela

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Geochemistry, mineralogy, and radioactivity of the Abu Furad Area, Central Eastern Desert, Egypt

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Acta Geochimica 2019年第2期38卷 307-326页

作者： a.m.el mezayen E.K.Abu Zeid W.S.Hosny m.G.el-Feky S.m.Omar S.A.Taalab Geology Department Faculty of Science Al Azhar University Nuclear material Authority Cairo Egypt

Abu Furad is in the Central Eastern Desert,Egypt. It comprises metasediments, metavolcanics,metagabbros, syn-to late-orogenic granites, and post-orogenic granites, in addition to numerous dykes and veins of different shapes and composition invading all the older rocks cropping out in the study area. Field, petrographic,mineralogical, and chemical investigations led to the classification of Abu Furad granites as quartz diorite, tonalite,granodiorite, and *** oxide and trace element data revealed that the syn-to late-orogenic granites and post-orogenic granites are peraluminous. Syn-to lateorogenic granites originated from calc-alkaline volcanic arc–related magma; while the post-orogenic granites(syenogranite) are highly fractionated, calc-alkaline granite from a within plate regime. Radiometrically, the studied quartz diorite, tonalite, and granodiorite had lower uranium and thorium contents and higher eU/eTh ratios than the syenogranites. This may indicate that the syn-to late-orogenic rocks originated from sources depleted in these elements. The average e Th/eU ratio of syenogranites was higher than that of average continental crust, suggesting that the syenogranites are relatively depleted in U. The studied altered syenogranites were strongly enriched in U and Th compared to the Earth's crust. On the other hand, the average of e U in pegmatites is lower than the global average for uraniferous pegmatites. The most recorded accessory minerals in the altered syenogranites were thorite, fergusonite, samarskite, columbite, zircon, monazite, xenotime,apatite, fluorite, sphene, atacamite, and malachite, in addition to chromium and nickel inclusions.

关键词： Hydrothermal alterations major oxide and trace elements Radiometry mineralogy Geochemistry Altered syenogranites Egypt

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Anodic voltammetric determination of gemifloxacin using screen-printed carbon electrode

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Journal of Pharmaceutical Analysis 2013年第2期3卷 132-136页

作者： Abd-elgawad Radi Amira Khafagy Amira el-shobaky Hatem el-mezayen Department of Chemistry Faculty of ScienceDumyat University Department of Chemistry Faculty of ScienceHelwan University

The electrochemical oxidation behavior and voltammetric assay of gemifloxacin were investigated using differential-pulse and cyclic voltammetry on a screen-printed carbon *** effects of pH,scan rates,and concentration of the drug on the anodic peak current were *** of gemifloxacin in Tris-HCl buffer（pH 7.0） exhibited a well-defined single oxidation peak.A differential-pulse voltammetric procedure for the quantitation of gemifloxacin has been developed and suitably validated with respect to linearity,limits of detection and quantification,accuracy,precision,specificity,and *** calibration was linear from 0.5 to 10.0 μm,and the limits of detection and quantification were 0.15 and 5.0 μ*** ranging from 96.26% to 103.64% were *** method was successfully applied to the determination of gemifloxacin in pharmaceutical tablets without any *** present in the tablets did not interfere in the assay.

关键词： Screen-printed carbon electrode Voltammetry Gemifloxacin Pharmaceutical analysis

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