| 1 | Petrology, geochemistry, radioactivity, and M–W type rare earth element tetrads of El Sela altered granites, south eastern desert,Egypt显示文摘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 character.These 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. | A.M.El Mezayen M.A.Heikal M.G.El-Feky H.A.Shahin I.K.Abu Zeid S.R.Lasheen | 2019 | Acta Geochimica2019，38，1： | 1 |
| 2 | Evaluation of natural radioactivity and radiological hazards in basement rocks from Gabel Abu El-Hassan in the North Eastern Desert of Egypt by multivariate statistical approach with remote sensing data显示文摘Purpose The present work deals with the natural radioactivity levels of basement rocks from Gabel Abu El-Hassan in the North Eastern Desert of Egypt.Methods The activity concentrations of 226Ra,232Th and 40K in rock samples were measured using a gamma-ray spectrometry with an HPGe detector.Landsat Enhanced Thematic Mapper Plus(ETM+)data were processed and interpreted to create rock forming radioactive map.Results and conclusion The activity concentrations of 226Ra,232Th and 40K varied from 28.2±9.4 to 259.6±38.6 Bq/kg,37.9±9.9 to 297.4±54.6 Bq/kg and 487.0±73.4 to 5514.6±786.0 Bq/kg,respectively.The radiological hazard indices(gamma index),the annual effective dose rate and excess life-time cancer risk were estimated to assess the radiological hazards due to the use of rock samples as building material.Remote sensing data were also used to integrate between radioactive analysis and Landsat-7(ETM+)data processing to detect radioactive anomalies and to identify the uraniferous alteration zones in Abu El-Hassan area. | Atef El-Taher Mostafa Kamel Abdellah Tolba Ghada Salaheldin | 2021 | Radiation Detection Technology and Methods2021，5，1： | 0 |
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