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Fluid effect on zircon O and U-pb isotopes during ultrahigh-pressure metamorphism:Insights from the Dora-Maira Massif of the Western Alps

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Geoscience Frontiers 2023年第6期14卷 210-223页

作者： Kun Zhou Yi-Xiang Chen Jia-Wei Xiong hans.Peter Schertl Xiao-Ping Xia CAS Key Laboratory of Crust-Mantle Materials and Environments School of Earth and Space SciencesUniversity of Science and Technology of ChinaHefei 230026China CAS Center for Excellence in Comparative Planetology University of Science and Technology of ChinaHefei 230026China Institute of Geology Mineralogy and GeophysicsFaculty of GeosciencesRuhr University Bochum44780 BochumGermany College of Earth Science and Engineering Shandong University of Science and TechnologyQingdao 266590China State Key Laboratory of Isotope Geochemistry Guangzhou Institute of GeochemistryChinese Academy of SciencesGuangzhou 510640China

Zircon geochemistry such as U-pb and O isotopes have been widely used in dating and tracing complex geological ***,it still remains unclear how fluid action affects zircon geochemistry during metamorphic and metasomatic processes in subduction *** a systematic study on zircon U-pb dating,O isotopes and trace elements as well as whole-rock O isotopes was carried out for the coesite-bearing whiteschists,jadeite quartzites and granitic gneisses from the Dora-Maira Massif,Western ***-rock and zircon geochemistry supports a common protolith,i.e.,Permian S-type granites,for the above three types of rocks and an intense fluid metasomatism during the Alpine orogeny to form whiteschists and jadeite *** cores in all samples have nearly identicalδ^(18)O values(9‰–11‰),whereas their apparent^(206)pb/^(238)U ages show a greater variability due to pb loss during *** rims formed in the late Eocene to early Oligocene can be categorized into two ***-Ⅰrims occur in granitic gneisses and jadeite *** have highδ^(18)O values consistent with zircon cores,but much lower contents of P and Y as well as lower Th/U ratios than the *** growth can be attributed to internal metamorphic fluid action at the UHP metamorphic ***-II rims occur in whiteschists and jadeite *** have remarkably lowerδ^(18)O values(5‰–8‰)and Th/U ratios(pb/^(238)U ages,which suggest the simultaneous impacts on U-pb-O isotopes during external fluid *** process can be attributed to the fluidassisted dissolution and recrystallization of protolith ***,coesite inclusions that would have been expected to occur only in young zircon rims formed duri

关键词： Subduction zone Fluid action Metasomatism Zircon O isotope U-pb dating

Metamorphic Evolution of Chloritoid-Bearing Micaschist from the Variscan Elstergebirge: Evidences for Stacking of High-Pressure Rocks in the Saxothuringian Zone of Central Europe

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Journal of Earth Science 2020年第3期31卷 425-446页

作者： Gelareh Rahimi hans.Joachim Massonne Fakultat Chemie Universitat Stuttgart70569 StuttgartGermany School of Earth Sciences China University of GeosciencesWuhan 430074China

A chloritoid-garnet-bearing micaschist from the southern part of the Elstergebirge was studied to better understand the Variscan orogenic evolution in the Saxothuringian zone of the northwestern Bohemian *** on the textural relations and compositions of minerals,especially of zoned garnet and potassic white mica,a P-T path was reconstructed using contoured P-T *** U-Th-pb dating of monazite in the micaschist was undertaken with the electron *** micaschist experienced P-T conditions along a clockwise path between 16 kbar at 510℃and 5 kbar at 555℃followed by isobaric heating to about 600℃.Monazite ages range between 315 and 480 Ma with the most prominent maxima and side maxima at 346.0±1.1(2σ),357.3±2.3,and 368.3±1.7 *** older than 380 Ma were related to detrital monazite pointing to a Devonian sedimentary *** ages around 325 Ma were assigned to the isobaric heating by nearby post-tectonic *** high-pressure event,being the result of the collision of Laurussia and Gondwana after closure of the Rheic Ocean,occurred in the Late *** exhumation to 15-20 km(5 kbar)ended probably in the Early *** high-pressure micaschists from the Fichtelgebirge to the Erzgebirge crystalline complexes are suggested to represent a single nappe within a metamorphic nappe *** nappe is composed of metasedimentary slices,which experienced different peak pressures rather than representing a coherent crustal section.

关键词： Saxothuringian micaschist chloritoid garnet monazite dating Variscan P-T path

Acclimatization of microalgae Arthrospira platensis for treatment of heavy metals in Yamuna River

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Water Science and Engineering 2020年第3期13卷 214-222页

作者： Nilesh Kumar Shriya hans.Ritu Verma Aradhana Srivastava University School of Chemical Technology Guru Gobind Singh Indraprastha UniversityNew Delhi 110078India

Bioaccumulation and biosorption in microalgae are effective approaches for the removal of heavy metals(HMs)from river *** objective of this study was to investigate the potential for use of acclimatized microalgae in the removal of HMs from the Yamuna River water as an acclimatizing *** active culture of Arthrospira platensis(***)was acclimatized to HMs up to a concentration of 100 mg/*** was gradually exposed to increasing concentrations of HMs in five subsequent batches with a step increase of 20 mg/L to acclimatize live cells in the simulated Yamuna River *** presence of high levels of HMs in the Yamuna River water caused growth *** empirical growth inhibition model was developed,and it predicted high threshold concentrations of HMs(210.7e424.5 mg/L),producing a positive specific growth rate of *** also showed high average removal efficiencies of HMs,including 74.0%for Cu,77.0%for Cd,50.5%for Ni,76.0%for Cr,76.5%for pb,and 63.5%for Co,from HMs-enriched Yamuna River *** findings demonstrated that the maximum specific removal amounts of Cu,Cd,Ni,Cr,pb,and Co were 54.0,58.0,39.0,62.8,58.9,and 45.3 mg/g,*** maximum yields of the value-added products chlorophyll and phycocyanin were 2.5 mg/g(in a batch of 40 mg/L for Cd)and 1054 mg/g(in a batch of 20 mg/L for Cu),***,acclimatized *** was proven to be a potential microalga not only for sequestration of HMs but also for production of valuable pigments.

关键词： Yamuna River A.platensis Heavy metals Acclimatization Biosorption Pigments

Geochemistry of volcanic glass from Mahanadi offshore region,eastern continental margin of India:Constraints on the contribution of latest Toba super-eruption

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Acta Oceanologica Sinica 2024年第2期43卷 111-119页

作者： Muralidhar Kocherla Durbar Ray Manavalan Satyanarayanan Hilda Joao Virsen Gaikwad pb Ramamurty CSIR-National Institute of Oceanography Dona Paula 403004GoaIndia CSIR-National Geophysical Research Institute Uppal RoadHyderabad 500007India

The tephra layers in multiple sediment cores from the offshore region of the Mahanadi basin in the northern Bay of Bengal were investigated for possible volcanic sources. The glass shards from those tephra layers were studied for size distribution, texture, and elemental geochemistry to establish chronostratigraphic markers for regional and global Quaternary correlation. The textural features of fine-grained(silty) volcanic glasses suggest the distal source of these tephra deposits. Major element composition with elevated SiO_(2) contents ranging between75%–76% and dominance of K_(2)O(> 4.5%) over CaO(< 0.9%) suggest ashes have originated from siliceous rhyolitic melts, similar to the petrographic composition of tephra from the Toba volcano. The bulk trace element compositions of the same glass shards were comparable with those reported in the youngest Toba tephra reported elsewhere. Likewise, the LREE-dominated chondrite normalized REE profiles of tephra from the Mahanadi basin closely resemble the characteristic REE patterns in Toba ash from other parts of the Indian Ocean and thus confirmed the contribution of the youngest Toba super-eruption for this ash layers.

关键词： Mahanadi basin Bay of Bengal volcanic glass glass morphology glass-chemistry

Past, present and future of fuel cells

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电池 2002年第3期32卷 130-132页

作者： A.C.C.Tseung(School of Chemical and Life Sciences,University of Greenwich,London SE18 6pb,UK) School of Chemical and Life Sciences University of Greenwich 英国

Though the fuel cell was invented by Grove in 1839,there are no commercially viable products at *** development of fuel cells can be conveniently divided into three phases exploratory phase(1839-1967).The main emphasis of the work is to increase the area of the three phase interface at the *** problem was solved by Bacon who invented the dual porosity,biporous nickel *** demonstrated the first H 2/O 2 fuel cell(180℃,20atm).This cell was later improved and scaled up to power the Apollo lunar ***,the cost is too high for civilian applications and we come to the development phase (1967-2001).The main emphasis has been on the use of Teflon bonded electrodes and novel catalysts(PtRu,Pt/WO 3 and Pt Ru/WO 3 anode catalyst for the anodic oxidation of impure H 2 and *** addition,the recent discovery of gadolinium doped ceria has reduced the operating temperature of solid oxide electrolytes to ～500℃ instead of 1?000℃.From 2001 onwards,we may be entering the breakthrough phase where the most favourable candidates are direct methanol vapor fuel cells and solid oxide electrolyte fuel *** the former case,there is a need to reduce the cross over of methanol to the cathode compartment and the development of air cathode catalyst which are less affected by methanol and in the latter case,there is a need to improve the activity of the anode and cathode catalysts.

关键词：燃料电池电催化反应电解液电极

Genetic associations with adverse events from anti-tumor necrosis factor therapy in inflammatory bowel disease patients

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World Journal of Gastroenterology 2017年第40期23卷 7265-7273页

作者： Daniel Lew Soon Man Yoon Xiaofei Yan Lori Robbins Talin Haritunians Zhenqiu Liu Dalin Li Dermot pb McGovern Department of Medicine Cedars-Sinai Medical Center F. Widjaja Foundation Inflammatory Bowel and Immunobiology Research Institute Cedars-Sinai Medical Center Department of Gastroenterology Cedars-Sinai Medical Center

AIM To study the type and frequency of adverse events associated with anti-tumor necrosis factor(TNF)therapy and evaluate for any serologic and genetic *** This study was a retrospective review of patients attending the inflammatory bowel disease(IBD) centers at Cedars-Sinai IBD Center from 2005-2016. Adverse events were identified via chart review. IBD serologies were measured by ELISA. DNA samples were genotyped at Cedars-Sinai using Illumina Infinium Immunochipv1 array per manufacturer's protocol. SNPs underwent methodological review and were evaluated using several SNP statistic parameters to ensure optimal allele-calling. Standard and rigorous QC criteria were applied to the genetic data, which was generated using immunochip. Genetic association was assessed by logistic regression after correcting for population *** Altogether we identified 1258 IBD subjects exposed to anti-TNF agents in whom Immunochip data were available. 269/1258 patients(21%) were found to have adverse events to an anti-TNF-α agent that required the therapy to be discontinued. 25% of women compared to 17% of men experienced an adverse event. All adverse events resolved after discontinuing the antiTNF agent. In total: n = 66(5%) infusion reactions; n = 49(4%) allergic/serum sickness reactions; n = 19(1.5%) lupus-like reactions, n = 52(4%) rash, n = 18(1.4%) infections. In Crohn's disease, Ig A ASCA(P = 0.04) and Ig G-ASCA(P = 0.02) levels were also lower in patients with any adverse events, and anti-I2 level in ulcerative colitis was significantly associated with infusion reactions(P = 0.008). The logistic regression/human annotation and network analyses performed on the Immunochip data implicated the following five signaling pathways: JAK-STAT(Janus Kinase-signal transducer and activator of transcription), measles, IBD, cytokine-cytokine receptor interaction, and toxoplasmosis for any adverse event. CONCLUSION Our study shows 1 in 5 IBD patients experience an

关键词： Genetic associations Inflammatory bowel disease Anti-tumor necrosis factor Adverse events

The Global boundary Stratotype Section and Point （GSSP） of the Ladinian Stage （Middle Triassic） at Bagolino （Southern Alps, Northern Italy） and its implications for the Triassic time scale

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Episodes 2005年第4期28卷 233-244页

作者： Peter Brack hans.Riebe Alda Nicora Roland Mundil Departement Erdwissenschaften ETH-Zentrum CH-8092 Zurich Switzerland. Palaontologisches Instituit Universitat ZurichCH-8006ZurichSwitzerland. Dipartimento di Scienze della Terra Universita di Milano Via Mangiagaiii 341-20133 Milano Italy. Berkeley Geochronology Center 2455 Ridge Road Berkeley CA 94709 USA

The Global boundary Stratotype Section and Point （GSSP） for the base of the Ladinian Stage （Middle Triassic） is defined in the Caffaro river bed （45°49＇09.5＂N, 10°28＇15.5＂E）, south of the village of Bagolino （Province of Brescia, northern Italy）, at the base of a 15-20-cm-thick limestone bed overlying a distinct groove （＂Chiesense groove ＂） of limestone nodules in a shaly matrix, located about 5 m above the base of the Buchenstein Formation. The lower surface of the thick limestone bed has the lowest occurrence of the ammonoid Eoprotrachyceras curionii （base of the E. curionii Zone; onset of the Trachyceratidae ammonoid family）. Secondary global markers in the uppermost Anisian include the lowest occurrence of conodont Neogondolella praehungafica and a brief normal-polarity magnetic zone recognized in closely correlated sections including the principal auxiliary section at Seceda in the Dolomites. The GSSP-level is bracketed by U-pb single zircon age data from volcaniclastic horizons, indicating a boundary age of ca 241 Ma.

关键词：三叠纪镧阿尔卑斯山意大利 GSSP