Mineral chemistry, whole-rock geochemical and Sr–Nd isotopic data are reported for the Abu-Diab granitoids in the northern Arabian-Nubian Shield (ANS) of Egypt, to investigate their petrogenesis and ...geodynamic significance. Gabal Abu-Diab constitute a multiphase pluton, consisting largely of two-mica granites (TMGs) enclosing microgranular enclaves and intruded by garnet bearing muscovite granites (GMGs) and muscovite granites (MGs). The granitoids are weakly peraluminous (A/CNK = 1.01–1.12) and show high SiO2 (>72.9 wt%) and alkali (K2O + Na2O = 8.60–9.13) contents. The geochemical features show that they are post-collisional and highly fractionated A-type granitoids. Compared to their host TMGs, the microgranular enclaves are strongly peraluminous (A/CNK = 1.18–1.24) with lower SiO2 and higher abundances of trace elements. The TMGs are depleted in Ba, Nb, P and Ti and are enriched in LREEs relative to HREEs with weakly negative Eu anomalies (Eu/Eu* = 0.45–0.64). In contrast, the GMGs and MGs are extremely depleted in Ba, Sr and Ti and have tetrad-type REE patterns (TE1–3 = 1.1–1.3) with strongly pronounced negative Eu anomalies (Eu/Eu* = 0.03–0.26), similar to rare metals bearing granites. The Ediacaran (585 ± 24 Ma) TMGs, are characterized by restricted and relatively low initial 87Sr/86Sr ratios (0.70337–0.70382) that suggests their derivation from a depleted mantle source, with little contamination from the older continental crust. In contrast, the GMGs and MGs have extremely high 87Rb/86Sr and 87Sr/86Sr ratios that reflect the disturbance of the Rb-Sr isotopic system and may give an indication for magmatic-fluid interaction. However, all the granitoids display positive εNd(t) (4.41–6.57) and depleted mantle model ages TDM2 between 777 and 956 Ma, which indicate their derivation from a Neoproterozoic juvenile magma sources and preclude the occurrence of pre-Neoproterozoic crustal rocks in the ANS. The microgranular enclaves represent globules of hot mafic magma that have injected and partly mixed with the colder and more felsic TMGs magma. Geochemical and isotopic data along with petrogenetic modelling, suggest that the TMGs were formed by low degrees of partial melting of the pre-existing I-type granodiorites, followed by extensive fractional crystallization and fluid fractionation to produce the geochemically specialized rare metals GMGs and MGs in the margin of Abu-Diab pluton. During the post-collisional stage of ANS and due to lithospheric delamination processes, the underplated fluid/volatile rich mantle magma had interplated and migrated upward to shallow crustal levels, through extensional faults/shear zones, and enhanced the partial melting and fractionation of granodiorites to eventually form Abu-Diab A-type granitoids.
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•The Abu-Diab pluton contains three highly fractionated A-type granitoids.•The Ediacaran age (585 ± 24 Ma) was confirmed using Rb-Sr method.•The young TDM2 model ages reflect the juvenile crustal nature of the granitoids.•The granitoids were formed by both partial melting and fractional crystallization.•Tectono-magmatic evolution model of the Abu-Diab granitoids was proposed.
Mineral and whole-rock chemistry of Red Sea rift-related Tertiary basalts from south Quseir city, central Eastern Desert of Egypt is presented to investigate their petrogenesis and relationship to ...tectonic processes. The south Quseir basalts (SQB) are classified as high-Ti (TiO
2
>2 wt.%) subalkaline transitional lava emplaced in an anorogenic tectonic setting. Their Mg# varies from 48 to 53 indicating the evolved nature of the SQB. Pearce element ratios suggest that the SQB magmas evolved via fractional crystallization of olivine + clinopyroxene ± plagioclase, but the absence of Eu anomalies argues against significant plagioclase fractionation. Clinopyroxene compositions provide evidence for polybaric fractionation of the parental mafic magmas. Estimated temperatures of crystallization are 1015 to 1207 °C for clinopyroxene and 1076 to 1155 °C for plagioclase. These values are interpreted to result from early stage crystallization of clinopyroxene followed by concurrent crystallization of clinopyroxene and plagioclase. The incompatible trace element signatures of the SQB (La/Ba = 0.08–0.10 and La/Nb = 0.89–1.04) are comparable to those of ocean island basalts (OIB) generated from an asthenospheric mantle source unaffected by subduction components. Modeling calculations indicate that the SQB primary magmas were derived from ~4–5% partial melting of a garnet-bearing lherzolite mantle source. The NE Egyptian basaltic volcanism is spatially and temporally related to Red Sea rifting and to the local E–W striking faults, confirming a relationship to tectonic activity. Our results suggest that the extensional regime associated with Red Sea rifting controlled the generation of the Egyptian basalts, likely as a result of passive upwelling of asthenospheric mantle.
The widely distributed granitic intrusions in the Nubian Shield can provide comprehensive data for understanding its crustal evolution. We present new bulk-rock geochemistry and isotopic (zircon U-Pb ...and Lu-Hf) data from the Haweit granodiorites in the Gabgaba Terrane (NE Sudan). The dated zircons presented a 206Pb/238U Concordia age of 718.5 ± 2.2 Ma, indicating that they crystallized during the Cryogenian. The granodiorites contain both biotite and amphibole as the main mafic constituents. The samples exhibit metaluminous (A/CNK = 0.84–0.94) and calc-alkaline signatures. Their mineralogical composition and remarkable low P2O5, Zr, Ce, and Nb concentrations confirm that they belong to I-type granites. They exhibit subduction-related magma geochemical characters such as enrichment in LILEs and LREEs and depletion in HFSEs and HREEs, with a low (La/Yb)N ratio (3.0–5.9) and apparent negative Nb anomaly. The positive Hf(t) values (+7.34 to +11.21) and young crustal model age (TDMC = 734–985 Ma) indicates a juvenile composition of the granodiorites. The data suggest that the Haweit granodiorites may have formed from partially melting a juvenile low-K mafic source. During subduction, the ascending asthenosphere melts might heat and partially melt the pre-existing lower crust mafic materials to generate the Haweit granodiorites in the middle segment of the Nubian Shield.
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•Gabal El-Ineigi is a composite pluton consists of two different granitic types.•Geochemically the two types are genetically not associated to each other.•Columbite, fluorite and ...other rare metal minerals are related to highly fractionated type.•The highly fractionated type is formed by open system fractionation via fluid interaction.•Fluorine in magma is responsible for formation of rare metal mineralization.
The Central Eastern Desert (CED) of Egypt, a part of Neoproterozoic Arabian Nubian Shield (ANS), embraces a multiplicity of rare metal bearing granitoids. Gabal El-Ineigi represents one of these granitic plutons and is a good example of the fluorite-bearing rare metal granites in the ANS. It is a composite pluton consisting of a porphyritic syenogranite (SG; normal granite) and coarse- to medium-grained highly evolved alkali-feldspar granite (AFG; fluorite and rare metal bearing granite) intruded into older granodiorite and metagabbro-diorite rocks. The rock-forming minerals are quartz, K-feldspar (Or94-99), plagioclase (An0-6) and biotite (protolithonite-siderophyllite) in both granitic types, with subordinate muscovite (Li-phengite) and fluorite in the AFG. Columbite-(Fe), fergusonite-(Y), rutile, zircon and thorite are the main accessory phases in the AFG while allanite-(Ce) and epidote are exclusively encountered in the SG. Texture and chemistry of minerals, especially fluorite, columbite and fergusonite, support their magmatic origin. Both granitic types are metaluminous to weakly peraluminous (A/CNK=0.95–1.01) and belong to the post-collisional A2-type granites, indicating melting of underplated mafic lower crust. The late phase AFG has distinctive geochemical features typical of rare metal bearing granites; it is highly fractionated calc-alkaline characterized by high Rb, Nb, Y, U and many other HFSE and HREE contents, and by extremely low Sr and Ba. Moreover, the REE patterns show pronounced negative Eu anomalies (Eu/Eu∗=0.03 and 0.06) and tetrad effect (TE1,3=1.13 and 1.27), implying extensive open system fractionation via fluid–rock interactions that characterize the late magmatic stage differentiation. The SG is remarkably enriched in Sr, Ba and invariably shows a relative enrichment in light rare-earth elements (LREEs). The SG rocks (569±15Ma) are characterized by relatively low initial 87Sr/86Sr ratios (0.7034–0.7035) that suggest their derivation from the mantle, with little contamination from the older continental crust. By contrast, the AFG has very high 87Rb/86Sr and 87Sr/86Sr ratios that reflect the disturbance of the Rb-Sr isotopic system and may give an indication for the high temperature magma-fluid interaction. The positive εNd(t) values of AFG (+7.40) and SG (+5.17), corresponding to young Nd-TDM2 ages ranging from 707 to 893 Ma, clearly reflect the juvenile crustal nature of Gabal El-Ineigi granitoids and preclude the occurrence of pre-Neoproterozoic continental crust in the ANS. The field relationships, chemical, petrological and isotopic characteristics of El-Ineigi SG and AFG prove that they are genetically not associated to each other and indicate a complex origin involving two compositionally distinct parental magmas that were both modified during magmatic fractionation processes. We argue that the SG was formed by partial melting of a mid-crustal source with subsequent fractional crystallization. In contrast, the AFG was generated by partial melting and fractionation of Nb- and Ta-rich amphibole (or biotite) of the lower crust. The appreciable amounts of fluorine in the magma appears to be responsible for the formation of rare metal element complexes (e.g., Nb, Ta, Sn and REEs), and could account for the rare metal mineralization in the El-Ineigi AFG.
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•The volcanic rocks in the Gabgaba Terrane were erupted during Tonian.•The volcanic rocks have positive εHf(t) values, indicative of derivation from a juvenile arc magmatism.•The ...depleted mantle source was metasomatized by slab-dehydration fluids.•The primitive magma was subjected to crustal assimilation prior to eruption.•The volcanic rocks were erupted during different stage of arc maturity.
An integrated study of zircon U-Pb geochronology and geochemistry together with Lu-Hf isotopes, has been carried out on basaltic andesite and andesite from the Haweit area (Gabgaba Terrane, NE Sudan) to indicate their magmatic evolution. In-situ U-Pb zircon dating yielded a weighted mean age of 752 ± 11 Ma for andesite and 773 ± 17 Ma for basaltic andesite, suggesting they were generated during Tonian. The Haweit volcanic rocks are generally sub-alkaline and tholeiitic lavas. They are characterized by low Mg# (29–44), low TiO2 (0.70–1.41 wt%), and relatively high Al2O3 (14.60–18.30 wt%) indicating that they are not a primitive melt. The nearly flat REEs pattern of the basaltic andesites indicate that they were formed in an immature island arc setting. While andesites are slightly enriched in LREE and LILEs, suggesting more mature island arc setting. The calculated Hf-TDMC (0.87–1.6 Ga) ages of zircons preclude the possibility of interaction of the parental magma with a pre-Neoproterozoic crustal source. The low (La/Yb)N (0.73–9.56) and high Zr/Nb (33–62) ratios, along with positive εHf(t) values (+1.33 to +12.5) indicate that the Haweit volcanic rocks were originated from depleted mantle with little crustal contamination. The geochemical data suggest that the parent magma of the Haweit volcanic rocks could be formed by low degree partial melting of spinel‐bearing Iherzolite depleted mantle metasomatized by slab‐derived fluids. The Haweit andesitic melts were later subjected to crustal assimilation before the final eruption of lavas during two stages of arc evolution.
Podiform chromitites hosted in serpentinites (after harzburgite and dunite) and talc‐carbonate rocks from the Abu Meriewa–Hagar Dungash district (MHD), Eastern Desert of Egypt, together with ...metagabbros, pillow metavolcanics, and metasediments, form an ophiolitic mélange formed during the Neoproterozoic Pan‐African Orogeny. The chromitites show massive, disseminated, and nodular textures. Chromite cores in chromitites have high and restricted ranges of Cr# (0.65–0.75) and Mg# (0.64–0.83), implying primary compositions not affected by metamorphism. Therefore, they are used as reliable indicators of parent magma composition and tectonic affinities of these highly metamorphosed rocks. On the contrary, the altered rims are high‐Cr, low‐Fe3+ spinel (rather than ferritchromit) enriched in Cr, Fe, and Mn, and depleted in Al and Mg (Cr# = 0.75–0.97, Mg# = 0.29–0.79), due to equilibration with interstitial silicates during regional metamorphism up to transitional greenschist–amphibolite facies at about 500–550°C. The primary chromite compositions suggest derivation from a high‐Mg tholeiitic, to possibly boninitic, parental magma in a supra‐subduction zone (arc–marginal basin) environment, similar to the spatially associated metavolcanic rocks. The MHD chromitites are most probably formed by melt–rock interaction mechanisms. The high Cr# of the investigated chromites suggests high degrees of partial melting of a depleted harzburgite source by interaction with primitive basaltic melt of deeper origin followed by mixing. Such Cr‐rich chromites are common in chromitites from the Eastern Desert of Egypt, implying broad thermal anomalies, possibly linked to an important geodynamic feature of the Arabian–Nubian Shield (ANS) evolution. This could revive interest in models that involve asthenospheric uprise, related to plume interaction or most probably due to oblique convergence of arc terranes during early evolution of the ANS.
Reducing the spread of SARS-CoV-2 was the primary focus of the Saudi public health authorities during the unprecedented COVID-19 pandemic.3 The 2020 and 2021 Hajj pilgrimages were appropriately ...scaled down with strict implementation of infection control measures, and no COVID-19 outbreaks were reported.4 With the easing of COVID-19 travel restrictions globally, increasing numbers of people travelled for the 2023 Hajj, during which Saudi Arabia hosted 1 845 045 pilgrims (969 694 male and 875 351 female), including 1 660 915 international pilgrims.5 A further substantial increase in these numbers, many of whom will be older people with comorbidities, is anticipated for the forthcoming Hajj pilgrimage in June, 2024. Global surveillance data show that, in addition to SARS-CoV-2, other viral respiratory pathogens, such as influenza A (H1N1), influenza B, human rhinovirus, respiratory syncytial virus, non-MERS-CoV human coronaviruses (eg, CoV-229E, CoV-OC43, CoV-HKU1, and CoVNL63), human metapneumovirus, and measles virus, are circulating at much higher concentrations worldwide than before the COVID-19 pandemic.6 Additionally, there is the increasing threat that various bacterial respiratory pathogens will be imported into Saudi Arabia and spread globally by pilgrims from across the world.7 Such pathogens include multi-antibiotic-resistant Mycoplasma pneumoniae, Chlamydia pneumoniae, Streptococcus pneumoniae, Haemophilus influenzae, Mycobacterium tuberculosis, Klebsiella pneumoniae, Moraxella catarrhalis, Legionella pneumoniae, Bordetella pertussis, and Pseudomonas aeruginosa, which, over the past 5 years, have continued to evolve and acquire additional antibiotic-resistance genes and are spreading globally.7–9 Pathogen spread and infection outcomes depend on many factors, such as the vaccination status of pilgrims before travel, adherence to the recommended local public health measures, the prevalence of pathogens in the pilgrims’ home countries, asymptomatic nasopharyngeal carriage, innate and herd immunity, pathogen evolution and mutations, and host susceptibility factors including extremes of age and underlying comorbidities such as diabetes and immunosuppressive conditions. Approved vaccines Target group Target countries Mandatory vaccines Meningococcal meningitis Quadrivalent (ACYW) polysaccharide vaccine between 10 days and 3 years before arrival or quadrivalent (ACYW) conjugated vaccine between 10 days and 5 years before arrival; health authorities at the pilgrims'; country of origin should ensure their vaccination within the required validity period and ensure that the type of vaccine and its date is clearly shown on the vaccination certificate—if the vaccine type is not indicated, it will be considered valid for 3 years only All individuals aged ≥1 year arriving for Hajj or for seasonal work in Hajj zones All countries Poliomyelitis At least one dose of IPV or bivalent OPV All travellers Countries reporting cases of WPV1 strains (Afghanistan, Mozambique, and Pakistan) or cVDPV1 strains (Madagascar, Mozambique, Malawi, DR Congo, Yemen, and Republic of the Congo) Poliomyelitis At least one dose of IPV* or, if IPV is not available, at least one dose of OPV† is acceptable All travellers Countries reporting human samples positive for the cVDPV2 strain or cases of acute flaccid paralysis Yellow fever Yellow fever vaccine; the vaccination certificate is valid for life starting 10 days after vaccination All travellers aged >9 months Countries or areas at risk of yellow fever transmission Recommended vaccines COVID-19 Pfizer–BioNTech; Moderna; Oxford–AstraZeneca; Janssen; Covovax; Nuvaxovid; Sinopharm; Sinovac; Covaxin; Sputnik-V All travellers aged ≥12 years intending to perform or attend Hajj All countries Poliomyelitis At least one dose of IPV* or, if IPV is not available, at least one dose of OPV† is recommended All travellers Countries reporting samples positive for the cVDPV2 strain from environmental surveillance Seasonal influenza Seasonal influenza vaccine Travellers arriving to Hajj areas for Hajj or seasonal work; particularly pregnant women, children aged <5 years, adults aged ≥60 years, and individuals with chronic medical or immunosuppressive conditions (eg, malignancy and HIV/AIDS) who are receiving chemotherapy or steroids Table Mandatory and recommended vaccines for pilgrims travelling to Saudi Arabia for the June, 2024 Hajj10
Objective:
The aim of this study was to assess of the effect of coronavirus disease 2019 (COVID-19) pandemic on urology practice in the Arab world during the first year of the crisis.
Methods:
An ...Internet-based questionnaire was created and sent out via email to members of the Arab Association of Urology (AAU) using ‘Google Forms’. The survey assessed participants’ demographics in terms of age, gender, country of origin, type of practice and position. Impacts of COVID-19 on urological practice were assessed in terms of the changes in hospital policies regarding consultations, and elective and emergency surgical cases. Moreover, impacts of COVID-19 on urologists were assessed.
Results:
A total of 255 AAU members across 14 Arab countries (Emirates, Egypt, Saudi Arabia, Iraq, Jordan, Algeria, Kuwait, Yemen, Qatar, Lebanon, Libya, Oman, Sudan and Syria) completed the survey; 4% were female urologists. Consultations at outpatient clinics were closed or restricted to emergency cases or replaced by telemedicine in almost 15%, 40% and 25% of hospitals, respectively. Elective surgeries were stopped or reduced to under 25% of surgical capacity in >10% and about 25% of hospitals, respectively. Almost 90% (228) reported changes in the policy for emergency theatres. Nearly 65% of hospitals offered preoperative COVID-19 testing to patients and 50% of hospitals provided personal protective equipment (PPE) to their urologists. Of 99% (253) who reported a change in urological education, 95% relied on online webinars. About 56% of respondents had their own private practice, of whom 91% continued private practice during the crisis. About 38% of participants reported exposure to intimidation (75% emotional, 20% verbal and 5% physical).
Conclusion:
The COVID-19 pandemic resulted in major changes in hospitals’ policies regarding outpatient consultations, elective and emergency operative cases, and the shift to telemedicine. Arab urologists have been facing major challenges either in both the governmental or the private sectors, and some of them were exposed to emotional, verbal and even physical intimidation.
A novel set of biologically active Co(II), Ni(II), Cu(II), Zn(II), and Cd(II) chelates was prepared from (E,Z)-methyl N-{(methylamino)carbonyloxy}ethanimidothioate. The chemical structural of the ...reported chelates was identified by means of some physicochemical and spectral approaches. All chelates were found to be non-electrolytic except Cd(II) possessed electrolytic character. The elemental analysis declared that the designated complexes were formed with (1:1), (2:1) and (1:3) (M:L) stoichiometry. The infrared spectral data revealed the neutral ONS tridentate and NS bidentate behavior of ligand towards metal ions. The octahedral structure of the produced chelates was proposed from the electronic absorption spectral data alongside the magnetic susceptibility measurements. TG/DTG demonstrated the superior complexes' thermal stability in comparison to that of free ligand. Ligand and its synthesized chelates were screened in vitro towards E. vermiculata for their anti-molluscicidal characteristic. The findings showed that each tested compound had varying degrees of sensitivity to the tested land snail species, with significant anti-molluscicidal action. In addition, ligand and its chelates were examined for their antibacterial screening towards both gram-positive (B. subtilis, S. aureus and M. sp. RCMB 028 (1)) and gram-negative bacteria (E. coli, P. aeruginosa and P. vulgaris) as well as their antifungal activity against C. albicans and A. fumigatus. The results indicated that the coordinated constructions have extraordinary activity compared to the ligand, in which Ni(II) and Cd(II) chelates were more active than the reference itself. X-ray diffraction data reflected that Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) crystallized at nano-scale. Some theoretical studies were validated, and the experimental results were interpreted.
Introduction
Influenza infection poses a significant public health threat. The core for disease prevention and control relies on strengthened surveillance activities, particularly in Saudi Arabia, ...the country that hosts the largest annual mass gathering event worldwide. This study aimed to assess the molecular and seasonal pattern of influenza virus subtypes in western Saudi Arabia to inform policy decisions on influenza vaccine.
Methods
This cross-sectional study was conducted at King Abdulaziz Medical City, western Saudi Arabia. Medical records and surveillance database of laboratory-confirmed influenza cases were reviewed from October 2015 to 2019. A panel of real-time polymerase chain reactions was performed to detect influenza A and B. Extracted RNA from a subset of positive samples was used to determine influenza A subtypes and influenza B lineages.
Results
This study included a total of 1928 patients with laboratory-confirmed influenza infections. Influenza peaks were observed in October each season, with variant predominant strains. Influenza virus subtypes co-circulate with no reports of co-infection. Influenza A(H3N2) was reported in 42% of the cases, then influenza B (30.7%) and influenza A(H1N1)pdm09 (27.3%). Healthcare workers represented 9.4% of the cases. One-third of the cases (30.4%) were admitted to the hospital with a median admission duration of 4 days. The influenza B viruses were subtyped in 218 cases. Victoria lineage was predominant (64.1%) in 2015 and 2016; however, Yamagata was predominant in the next two consecutive seasons (94.4% and 85.4%, respectively).
Conclusion
The burden due to influenza B may be underestimated with an observed vaccine mismatch. A quadrivalent influenza vaccine is recommended to reduce the health impact associated with influenza B infections. Molecular surveillance of the influenza viruses should be enhanced continuously for a better understanding of the influenza activity and assessment of vaccine effectiveness.
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