检索结果-南通市图书馆

Mapping Structurally Controlled Alterations Sparked by Hydrothermal Activity in the Fatira–Abu Zawal Area,Eastern Desert,Egypt

在线全文

学校读者我要写书评

暂无评论

Acta Geologica Sinica(English Edition) 2023年第2期97卷 662-680页

作者： Mohamed BADAWI Mahmoud ABDELATIF Ali SHEBL Farid MAKROUM Ahmed SHALABY Norbert NéMETH Institute of Exploration Geosciences University of MiskolcMiskolc 3515Hungary Department of Geology Mansoura UniversityMansoura 35516Egypt Department of Geology South Valley UniversityQena 83523Egypt Department of Mineralogy and Geology University of DebrecenDebrecen 4032Hungary Department of Geology Tanta UniversityTanta 31527Egypt

The Eastern Desert of Egypt suffered a protracted period of deformation triggered by cratonization of the new juvenile crust known as the Arabian Nubian Shield(ANS),which has been proposed for potential gold discoveries associated with the corresponding tectonic event.The Fatira area,on the border of Egypt’s Northern and Central Eastern Deserts,is covered with metavolcanic rocks twisted by a dextral relocation of the Fatira Shear Zone(FSZ)relative to the Barud magmatic body.The recent study evaluated many deformed post-orogenic granitic intrusions and felsite dikes associated with promising mineralization localities,notably orogenic gold deposits.The combination of various field observations and remote sensing data,followed by the analysis of aeromagnetic enhanced maps,allowed the differentiation of distinct lithologies,structural features,and hydrothermal alterations in the study area.Additionally,the integrated results obtained from the different interpretation techniques are utilized to identify and confirm the previously supposed mineralized localities in the Fatira and Abu Zawal areas and predict other matched localities.The final ASTER,Sentinel 2 hydrothermal alteration,and orientation entropy heat maps demonstrate the association between these mineralized regions and major structures related to the FSZ late stage of deformation rather than other structures studied throughout the area of interest.

关键词： gold granite island arc association Pan-African Orogeny Egypt

Geochemistry of island arc assemblage in the Eastern Desert of Egypt and the role of Pan-African magmatism in crustal growth of the Arabian–Nubian Shield:A review

在线全文

学校读者我要写书评

暂无评论

Acta Geochimica 2024年第3期43卷 588-622页

作者： Abdel-Aal MAbdel-Karim Mohamed MHamdy Adel A.Surour Geology Department Faculty of ScienceZagazig UniversityZagazig 44519Egypt Geology Department Faculty of ScienceTanta UniversityTanta 31527Egypt Department of Geological Sciences Faculty of ScienceNew Galala City 43511Egypt Geology Department Faculty of ScienceCairo UniversityGiza 12613Egypt

Neoproterozoic island arc assemblage of the Arabian–Nubian Shield(ANS)in the Eastern Desert(ED)of Egypt comprises juvenile suites of metavolcanics(MV),large amounts of meta-sedimentary rocks(MS),and voluminous metagabbros-diorites(MGD)and syn-tectonic intrusions of older granitoids(OG).We report here the updates of these four rock units in terms of classification,distribution,chemical characteristics,geodynamic evolution,metamorphism,and ages.In addition,we discuss these integrated data to elucidate a reasonable and reliable model for crustal evolution in the ANS.The main features of these rock units indicate their relation to each other and the geodynamic environment dominated by early immature oceanic island arcs to primitive continental arcs.Integrated information of the island arc metavolcanic and plutonic rocks(gabbros,diorites,tonalites,and granodiorites)furnish evidence of the genetic relationships.These include proximity and a coeval nature in the field;all protolith magmas are subalkaline in nature following calc-alkaline series with minor tholeiitic affinities;common geochemical signature of the arc rocks and subduction-related magmatism;their similar enrichment in LREEs;and similar major element compositions with mafic melts derived from metasomatized mantle wedge.The volcano-sedimentary and the OG rocks underwent multiphase deformation events whereas the MGD complexes deformed slightly.Based on the magmatic,sedimentological,and metamorphic evolutions constrained by geochronological data as well as the progressive evolutionary trend from extensional to compressional regimes,a possible gradual decrease in the subducted slab dip angle is the most infl uential in any geodynamic model for arc assemblage in the ED of Egypt.

关键词： Island arc assemblage Magmatism Crustal growth Neoproterozoic Arabian–Nubian Shield Eastern Desert Egypt

Geochemical and mineralogical characteristics of some gold mine tailings in the Eastern Desert of Egypt

在线全文

学校读者我要写书评

暂无评论

Frontiers of Earth Science 2022年第4期16卷 906-915页

作者： Mostafa REDWAN Geology Department Faculty of ScienceSohag UniversitySohag 82524Egypt

The adverse environmental effects of mine tailings disposal on the surrounding ecosystems are world-wide environmental problems.Due to environmental issues related to tailings discharged on land surface,detailed tailings characterization is a prerequisite for a long-term management solution.The tailings from four gold mines in Egypt,namely Fatira,El Sid,Barramiya,and Atud were investigated for their geochemical-mineralogical features and the effect of weathering behavior on the release of their heavy elements.The tailings samples were investigated by mineralogical(XRD and ESEM-EDS),physical(grain-size distribution)and geochemical(XRF)techniques.Most of the tailings have uniform silt-size with fine to very finesand and clay.Atud tailings have coarse to fine sands.High carbonate,predominantly calcite was found for the samples from Fatira and Atud,calcite-ankerite from El Sid and dolomite from Barramiya with little sulfide-content.High-mean of Cr(569287 mg/kg),Ni(89191 mg/kg)and Co(4221 mg/kg)values are coinciding with the ultramafic nature in Atud and Barramiya tailings.El Sid tailings have a high-mean concentration of Zn(1357 mg/kg)and Pb(1349 mg/kg).Barramiya tailings have a high-mean As concentration(2635 mg/kg).The Fatira tailings are characterized by high-mean values of Sr(444 mg/kg)and Cu(280 mg/kg)arising from auriferous mineralization.High Sr concentrations in Fatira tailings are mainly due to its adsorption to iron oxides.Pyrite oxidation is conceded along the cracks and/or the edges of the crystals in the El Sid,Barramiya and Atud tailings.The Threshold Effect Level(TEL)values indicated high contamination from heavy elements to the neighboring ecosystem.The tailings were deposited downstream into the small wadis.Wind and water erosion can dissolve efflorescent materials enriched in toxic elements like As,Zn,and Pb at tailings surface.The release of contaminants could be catastrophic for the environment without mine site rehabilitation strategies.

关键词： gold mine tailings geochemistry mineralogy Egypt

The possible source of uranium mineralization in felsic volcanic rocks,Eastern Desert,Egypt of the Arabian-Nubian Shield:Constraints from whole-rock geochemistry and spectrometric prospection

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acta Geochimica 2021年第5期40卷 819-845页

作者： Gehad.M.Saleh Bahaa.M.Emad Ibrahim.B.Abdel Kader Rania.M.Sakr Nuclear Materials Authority El MaadiP.O.Box 530CairoEgypt

The present work deals with the detailed geology,mineralogy,geochemistry,and spectrometric prospection of the felsic volcanic rocks at the Eastern Desert,Egypt of the Arabian-Nubian Shield.Felsic volcanic rocks are an essential source for rare earth elements(REEs)and uranium occurrences in this area.They are compositionally uniform with tholeiitic to calc-alkaline affinities,peraluminous and belong to the series of rhyolite with high-K melt.They exhibit more enrichment in high field strength elements(HFSE,e.g.Zr,Ta,Nd,Th,and U)and large-ion lithophile elements(LILE,e.g.Pb and Rb)compared to the country rocks of the studied area,with REE ranging from 188.20 to 442.70 ppm and strong depletion in Ti,Sr,P with deep negative Eu oddities.The felsic volcanic rocks were mostly generated from the partial melting of quartz-amphibolite facies accreted during the Neoproterozoic.Positive oddities of Zr-U-Th for the felsic volcanic rocks determine the involvement of crustal materials.Felsic volcanic rocks are found in A-type suites of magma and represent highly fractionated rocks derived from rhyolitic magma,with insignificant interaction with continental crust in the low-pressure environment and during fractional crystallization.Felsic volcanic rocks have higher values of radioactivity in which eU range from 0.5 to 121 ppm and eTh from 1.0 to 415.10 ppm.The high values of eU and eTh can be ascribed to the mineralization of uranium and the presence of accessory minerals of radiogenic nature such as uranophane,uranothorite,zircon,and monazite.Uranophane is considered as the mineral with most enriched uranium contents in the studied felsic volcanic rocks in which(UO2=87.30 wt%).Also,they are enriched with REE-bearing accessory minerals comprising allanite,titanite,and apatite.The geological investigations of the felsic volcanic rocks in the studied areas are inappropriate to clear the feasible economic potentialities of rare earth elements and U occurrences;itemized and invaluable explorational work is as yet needed.Whilst,the e

关键词： Felsic volcanic rocks Geochemistry REE Uranium mineralization Egypt Arabian-Nubian Shield

Geochemistry and spectrometric prospection of younger granites and granitic pegmatites bearing uranium mineralization at G.Kab El Rakeb area, Central Eastern Desert, Egypt

在线全文

学校读者我要写书评

暂无评论

Acta Geochimica 2021年第4期40卷 575-601页

作者： Gehad M.Saleh Bahaa M.Emad Ibrahim B.Abdel Kader Nuclear Materials Authority El MaadiP.O.Box 530CairoEgypt

The present study deals with the detailed field geology,mineralogy,geochemistry,and spectrometric prospection of rare metals and radioactive minerals associated with granitic pegmatites in the Gabal Um LassafAbu Dob-Um Atelia-Kadabora-Kab El Rakeb area(LDAKK),which are situated in the central Eastern Desert of Egypt.The study area is composed of granodiorites and monzogranites.The latter is dissected by granitic pegmatites with a discriminatory distribution of economically important mineralization(rare-metals and U-Th minerals).The granitic pegmatites display a zoning structure composed of feldspar-rich zones enveloping pockets of mica(mostly muscovite) and all zoning internal quartz core.Microscopically,the monzogranite and granitic pegmatites are composed of potash-feldspar,albite,and quartz with a small amount of biotite and muscovite.The mineralogical investigation of the highly radioactive zones in the granitic pegmatite shows enrichment in kasolite,uranothorite,thorite,xenotime,columbite,zircon,bismuth,and galena.Geochemically,the granitic pegmatites are enriched with high field strength elements(HFSE;Zr,Nb,Th,and U) and ion lithophilic elements(LILE;Rb,and Pb) and depleted in Ba,Sr,and Eu.They are strongly peralkaline to metalumainous except for two samples,which are peraluminous.They are formed by partial melting of metagreywackes at depth.The studied granitic pegmatites could belong to the NYF family(Niobium-Yttrium-Fluorine family) according to the geochemistry of the trace elements.The studied granitic pegmatites show deep negative Eu anomaly and display a strong M-type tetrad effect of rare earth elements.The field spectroscopy measurements showed the localization of the radiometric anomalous associated with the granitic pegmatites,which are intruded in the granitic host rocks.Their eU and eTh contents reached up to 316 and 1367 ppm,respectively.Uranium and thorium occurrences in the investigated granitic pegmatites are related to magmatic(syngenetic)origin with hydrothermal(epigenetic) input.The magm

关键词： Geochemistry Gabal Um Lassaf-Abu Dob-Um Atelia-Kadabora-Kab El Rakeb area(LDAKK) Uranium REE Egypt

On the Validity and Evolution of Assilina Species during the Ypresian–Lutetian:Example from Bir Dakhl,Eastern Desert,Egypt

在线全文

学校读者我要写书评

暂无评论

Acta Geologica Sinica(English Edition) 2021年第4期95卷 1080-1085页

作者： Safia AL MENOUFY Mohamed BOUKHARY University of Ain Shams Faculty of EducationDepartment of Biological&Geological SciencesCairo 11341Egypt Geology Department University of Ain ShamsFaculty of ScienceCairo 11566Egypt

The genus Assilina is a taxon within the Nummulitacea that appeared early in the Ypresian(Early Eocene)and continued until the end of the Lutetian(Middle Eocene).Thus,this taxon could be useful for the chronostratigraphy of this time interval.Lower Eocene rocks in southern Galala,Egypt are exposed at Bir Dakhl.This section includes marl sediments with debris flow shallow-marine facies deposits laid down during early Eocene times and includes fossils of large foraminifera:Assilina placentula Deshayes,1838 and Nummulites burdigalensis de la Harpe,1926.These are systematically treated,described and illustrated.Nummulites burdigalensis belongs to the N.burdigalensis group,and Assilina placentula belongs to the group of Assilina exponens.This assumption is based on qualitative morphology and quantitative measurements.Both species,together with Operculina libyca Schwager,1883,enable the assignment of the Bir Dakhl(D5-40 Section)to the Early Eocene,Ypresian(SBZ10 of Serra-Kiel et al.,1998)supporting an earlier opinion that Assilina placentula belongs to that zone in the calibrated larger foraminiferal biostratigraphic zonation.

关键词： foraminifera Assilina evolution Eocene Galala Egypt

The Prevalence and Risk Factors of Elder Abuse during the COVID-19 Pandemic in the Fayoum Governorate,Egypt

在线全文

学校读者我要写书评

暂无评论

Journal of Forensic Science and Medicine 2023年第3期9卷 257-263页

作者： Marwa Ali Mwaheb Asmaa Younis Elsary Amal Raouf Saleh Department of Forensic Medicine and Clinical Toxicology Faculty of MedicineFayoum UniversityFaiyumEgypt Department of Public Health and Community Medicine Faculty of MedicineFayoum UniversityFaiyumEgypt

Background: Elder abuse has evolved into a global public health and human rights issue. COVID-19 had a significant impact on Egypt’s economic development and style of life. Aim: This research aimed to estimate the prevalence of elder abuse in the Fayoum Governorate of Egypt during the COVID-19 pandemic and assess the prevalence of different elder abuse subtypes and study the effect of different demographic characteristics on these abuse subtypes. Methods: This study was a cross-sectional, descriptive survey among 201 older adults aged 60 and above in the Fayoum Governorate. The structured questionnaire used in the study had three sections: demographic characteristics, the Hwalek- Sengstock elder abuse screening test, and the Questions to Elicit Elder Abuse screening tool. Results: This research documented that the prevalence of elder abuse was (72.6%) and the most prevalent types were emotional and neglect abuse (71.1% and 64.7%, respectively). In our study, 22.9% of older adults were exposed to a single type of abuse, 29.9% to two types, 26.9% to three types, and 10.4% to four types. Female is significantly higher than male abuse exposure (66.7% vs. 33.3%). 52.4% versus 7.1% were more likely to be abused than elderly persons who earn enough income. Conclusion: According to this study, emotional and neglect abuse were the most common types of elder abuse. Risk factors for elder abuse included being between the ages of 60 and 70 years, being a woman, residing in a rural location, being illiterate, jobless, married, earning little money, and belonging to a middle-class socioeconomic group. For the general public to better comprehend the consequences of elder abuse on their health and human rights, awareness and education must be increased.

关键词： Abuse Egypt elderly mistreatment old age

Geochemical constraints and uranium potential of the younger granitic rocks in El Maghrbia area, Central Eastern Desert, Egypt

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acta Geochimica 2021年第4期40卷 623-639页

作者： A.E.El-Kammar A.H.El-Afandy T.Nasr M.Coltorti F.Casetta Department of Geology Faculty of ScienceCairo UniversityCairoEgypt Nuclear Materials Authority El MaadiCairoEgypt Department of Physics and Earth Sciences University of FerraraFerraraItaly

The present work deals with the mineralogy,geochemical behavior and uranium potentiality of the monzogranites of El Maghrbia area,which comprise G.El Maghrbia and G.El Eredyia and situated in the central Eastern Desert of Egypt.G.El-Erediya monzogranites represents a promising area for uranium mineralizations.These granites have shear zone filled with red and black silica veins containing many radioactive anomalies with visible yellow secondary uranium minerals.The shear zone is highly affected by different degrees of alterations such as silicification,kaolinitization,sassuritization and ferrugination.Monzogranites of El-Erediya area possess higher values of their radioactivity than in El Maghrbia monzogranites in which eU and eTh,reaches up to 792.3 and 66.81 ppm,whilst average content of eU and eTh in El Maghrabia granites are 3.86 and 8.55 ppm,respectively owing to the presence of radioactive minerals such as uraninite,uranothorite,uranophane,kasolite,betafite,zircon and monazite.Intensive geochemical analyses indicated that,the studied monzogranites are distinctly anomalous in U,where the average U is more than 620-fold the Upper Continental Crust(UCC),marked enrichment(> tenfold) of the elements Cd,Mo,Pb,Bi,Nb and W.The Th/U ratio decreases from 2.8,as a chondritic value,to 0.0023 for the studied granites,proposing extreme fractionation towards an extensive secondary migration-in of U.The Zr and Hf are depleted in the studied granites relative to the UCC,whereas Nb and Ta are strongly enriched.The content of Y is about sixfold enriched which reflects relative enhancement of the HREE during the alteration processes.Uranium correlates with Fe_(2)O_(3),suggesting a possible association between uranium and ferrugination.Thus,the occurrences of uranium are epigenetic by remobilization from the host rock to the sheared zones,probably through metasomatic process where U-Fe-Mg replaced the feldspars in an oxidized condition.The high levels of radioactivity in the rocks being studied it them a priority for discovery

关键词： Potentiality Uranium Geochemistry El Maghrabia El Erediya Egypt

Elimination of schistosomiasis requires multifactorial diagnostics: evidence from high- and low-prevalence areas in the Nile Delta, Egypt

在线全文

学校读者我要写书评

暂无评论

Infectious Diseases of Poverty 2020年第2期9卷 63-75页

作者： Hala Elmorshedy Robert Bergquist Amel Fayed Wafaa Guirguis Ensaf Abdel-Gawwad Safaa Eissa Rashida Barakat College of Medicine Princess Nourah bint Abdulrahman UniversityP.O.Box:84428Riyadh Postal Code:11671Saudi Arabia High Institute of Public Health Alexandria UniversityAlexandriaEgypt Ingerod SE-45494 BrastadSweden

Background:Schistosomiasis is one of the neglected tropical diseases(NTDs)selected for worldwide elimination in the near future.Egypt has made strong progress against its two endemic species of Schistosoma mansoni and S.haematobium.The former is prevalent in the Nile Delta with the latter dominating in the Nile south of Cairo.Innovative efforts are needed to reach the goal as further reduction of the prevalence has stalled due to ongoing transmission.In this study we aimed to explore the difference between low and high prevalence villages with regard to knowledge attitude and practice about schistosomiasis,utilization of health services,infection and transmission indices.Methods:A hybrid cross-sectional longitudinal study was conducted with three annual follow-ups conducted during 1994-1996.We used a representative systematic random sampling technique investigating 993 individuals from the high prevalence village and 614 from the low prevalence village.Data were analyzed using SPSS,comparing proportions with the Chi square test and means with the Student t test,and ANOVA.Results:Compliance of faecal sampling and chemotherapy was above 70%in both villages over the whole study period.Selective praziquantel treatment resulted in a significant reduction of prevalence and intensity of infection in both villages,dropping from 35.8%prevalence to 20.6%,in the low-prevalence village,and from 69.5 to 45.9%in the high-prevalence one.Intensity of infection at the base line was 30 eggs per gram(EPG)of stool in the low-prevalence village versus 105 EPG in the high-prevalence village.However,after the second round,reinfection rebounded by 22%in the high-prevalence village,while a slight improvement of the infection indices was demonstrated in the low-prevalence one.The level of knowledge was modest in both villages:people knew about self-protection and treatment,but not much about the role of human excreta for schistosomiasis transmission.While all participants maintained that using the water from the canals was inevitable,inha

关键词： Schistosomiasis Transmission Praziquantel Knowledge attitude and practice Utilization of health services Poverty Egypt