Mineralogy,geochemistry,radioactivity and environmental impacts of Gabal Marwa granites,southeastern Sinai,Egypt

作     者：El Feky M.G. El Mowafy A.A. Abdel Warith A. 

作者机构：Nuclear Materials AuthorityMaadiCairoEgypt 

出 版 物：《Chinese Journal Of Geochemistry》 (中国地球化学学报)

年 卷 期：2011年第30卷第2期

页      面：175-186页

核心收录：

学科分类：0709[理学-地质学] 070901[理学-矿物学、岩石学、矿床学] 07[理学] 

主　　题：granodiorite monzogranites 放射性 Gabal Marwa 西奈 埃及 

摘      要：The Gabal Marwa area is located in the southeastern part of Sinai,*** comprises gneisses and migmatites,granodiorites and ***,petrographic,mineralogic and chemical investigations indicated that the Gabal Marwa granites are classified as granodiorites and *** monzogranites constitute the most predominant rock unit exposed in the study *** have been subjected to hydrothermal alterations,especially along the shear ***,desilicification,nametasomatism and development of spotty or dendritic manganese oxides are the most pronounced alteration *** alterations resulted in the increase of TiO2,Al2O3,FeOt,MnO,CaO,MgO,Na2O,K2O and Cr,Zr,Rb,Y and Sr and the decrease of SiO2,P2O5,Ni,Zn,Ba and *** studies indicated that the altered granites belong to high thorium,high uranium *** U,Th,U and Th,Th/U,Th and U-K variation diagrams suggested that magmatic processes controlled the distribution of these elements but the effect of hydrothermal alteration processes were clearly *** Scanning Electron Microscope and X-ray Diffraction analyses indicated that the most important radioactive minerals include uranothorite,thorite,zircon,monazite and *** and Mn minerals were also *** the U,Th,Ra and K activity concentrations obtained for all the studied granitic samples,radium equivalent activity(Raeq),external hazard index(Hex),and internal hazard index(Hin),were calculated to assess the radiation hazard to human beings living in dwellings made of the studied *** monzogranites have radioactivity above the proposed acceptable level and,therefore,caution must be taken when these granites are used as building materials.