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Strategies towards robust interpretations of in situ zircon Lu-Hf isotope analyses

Geoscience Frontiers 2020年第3期11卷 843-853页

作者： C.j.Spencer C.L.Kirkland n.M.W.Roberts n.j.evans j.Liebmann School of Earth and Planetary Sciences The Institute for Geoscience Research(TIGeR)Curtin UniversityPerthAustralia Department of Geological Sciences and Geological Engineering Queen’s UniversityKingstonCanada Centre for Exploration Targeting-Curtin node The Institute for Geoscience ResearchSchool of Earth and Planetary SciencesCurtin UniversityPerthAustrali Geochronology and Tracers Facility British Geological SurveyNottinghamUK john de Laeter Centre GeoHistory Facility School of Earth and Planetary SciencesCurtin UniversityPerthAustralia

The combination of U-Pb and Lu-Hf compositions measured in zircon crystals is a remarkably powerful isotopic couplet that provides measures on both the timing of mineral growth and the radiogenic enrichment of the source from which the zircon *** U-Pb age documents the timing of zircon crystallization/recrystallization and Hf isotopes inform on the degree to which the host melt was derived from a radiogenic reservoir(*** mantle) versus an unradiogenic reservoir(*** continental crust),or some mixture of these *** ease of generating large quantities of zircon U-Pb and Lu-Hf data has been in large part facilitated by instrument ***,the dramatic increase in time constrained zircon Lu-Hf analyses in the Earth science community has brought to the fore the importance of careful data collection and reduction workflows,onto which robust geological interpretations may be *** this work,we discuss the fundamentals of Lu-Hf isotopes in zircon,which then allows us to provide a robust,accessible,methodology for the assessment of data ***,we discuss some novel techniques for:data visualization—that facilitates better transparency of data interpretation;integration of geographic information—that may reveal spatial trends where temporal trends were only apparent before;and some novel statistical evaluation tools—that may provide more rigorous interand intra-sample comparisons.

关键词： Zircon Geochronology Isotope geochemistry Lu-Hf isotopes Geostatistics Data visualization

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Zircon geochronology reveals polyphase magmatism and crustal anatexis in the Buchan Block,nE Scotland:Implications for the Grampian Orogeny

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Geoscience Frontiers 2017年第6期8卷 1469-1478页

作者： T.E.johnson C.L.Kirkland D.R.Viete S.Fischer S.M.Reddy n.j.evans B.j.McDonald Department of Applied Geology The Institute for Geoscience Research(TIGeR)CET-Curtin NodeJohn de Laeter CentreCurtin UniversityPerthWA 6102Australia Morton K.Blaustein Department of Earth&Planetary Sciences Johns Hopkins UniversityOlin Hall3400 N Charles StreetBaltimoreMD 21218USA School of Earth&Environmental Science University of St AndrewsIrvine BuildingNorth StreetSt AndrewsKY16 9ALScotlandUK

The type locality for high-temperature,low-pressure regional metamorphism,the Buchan Block in nE Scotland,exhibits profound differences to the rest of the Grampian *** differences have led some to regard the Buchan Block as an exotic crustal fragment comprising Precambrian basement gneisses and cover rocks thrust into their current position during Grampian *** rocks of the Buchan Block are now generally correlated with Dalradian strata elsewhere,the origin of the gneisses and the cause of the high heat flow and associated magmatism is *** report SIMS U-Pb and LA-ICPMS Hf isotopic data in zircon from high-grade rocks from the northeast(Inzie Head Gneiss)and northwest(Portsoy)corners of the Buchan *** Inzie Head,upper amphibolite to granulite facies metasedimentary gneisses coexist with diorite sheets that were emplaced contemporaneously with partial melting of their host rocks,at least locally.U-Pb geochronology indicates a crystallisation age for the diorite of 486±9 ***-deformed diorites within the Portsoy Gabbro have a crystallisation age of 493±8 *** of ca.490 Ma for magmatism and high-grade metamorphism,which are broadly contemporaneous with ophiolite obduction and the onset of orogenesis,are significantly older than the established peak of Grampian metamorphism(ca.470 Ma).We propose a new model for the Grampian Orogeny involving punctuated tectonothermal activity due to tectonic switching during accretionary *** of a nW-dipping subduction zone at ca.490 Ma produced a back-arc environment(the Buchan Block)with associated arc magmatism and high dT/dP *** of an outboard arc resulted in shortening(the initial phase of the Grampian Orogeny)at ca.488 *** of a nW-dipping subduction zone to the SE of the ca.488 Ma suture began at 473 Ma and led to lithospheric-scale extension,decompression melting and advective heating of the middle crust,producing the widespread ca.470 Ma Gram

关键词： Dalradian Grampian Orogeny Buchan Block Zircon geochronology Magmatism Metamorphism

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新生儿的经皮呼吸

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宁夏医科大学学报 1987年第2期 88-88页

作者： n.j.evans n.Rutter 刘新远

1851年,Gerlach氏首先证实人的皮肤不断地吸收氧和排泄二氧化碳。对成人的这一现象进行了广泛的研究,据测定,呼吸总量的1～2％是经皮发生的。但尚未见直接测定新生儿的经皮气体交换。作者研究了27例新生儿(出生体重0.96～4.43kg,妊娠27... 详细信息

1851年,Gerlach氏首先证实人的皮肤不断地吸收氧和排泄二氧化碳。对成人的这一现象进行了广泛的研究,据测定,呼吸总量的1～2％是经皮发生的。但尚未见直接测定新生儿的经皮气体交换。作者研究了27例新生儿(出生体重0.96～4.43kg,妊娠27～40周)的经皮呼吸。结果

关键词：新生儿经皮足月儿

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Improving modeling of low-altitude particulate matter emission and dispersion:A cotton gin case study

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journal of Environmental Sciences 2023年第11期133卷 8-22页

作者： Zijiang Yang Michael n.evans Michael D.Buser Cathleen j.Hapeman Alba Torrents Derek P.Whitelock Department of Civil and Environmental Engineering University of Maryland College Park1173 Glenn L.Martin HallCollege ParkMaryland 20742United States Department of Geology University of Maryland College Park1212B Chemistry BuildingCollege ParkMaryland 20742United States Earth System Science Interdisciplinary Center 1120 Geology BuildingUniversity of MarylandCollege ParkMaryland 20742United States United States Department of Agriculture Agricultural Research ServiceOffice of National Programs5601 Sunnyside Ave(GWCC 4–2282)BeltsvilleMaryland 20705United States United States Department of Agriculture Agricultural Research ServiceHenry A.Wallace Beltsville Agricultural Research Center10300 Baltimore AvenueBeltsvilleMaryland 20705United States United States Department of Agriculture Agricultural Research ServiceSouthwestern Cotton Ginning Research LaboratoryPO Box 578Mesilla ParkNew Mexico 88047United States

Monitoring and modeling of airborne particulate matter(PM)from low-altitude sources is becoming an important regulatory target as the adverse health consequences of PM become better ***,application of models not specifically designed for simulation of PM from low-altitude emissions may bias *** address this problem,we describe the modification and validation of an air dispersion model for the simulation of lowaltitude PM dispersion from a typical cotton ginning *** found that the regulatory recommended model(AERMOD)overestimated pollutant concentrations by factors of 64.7,6.97 and 7.44 on average for PM 2.5,PM 10,and TSP,*** concentrations were negatively correlated with height(pnce from source(pnd standard deviation of wind direction(pnd positively correlated with average wind speed(pn these results,we developed dispersion correction factors for AERMOD and cross-validated the revised model against independent observations,reducing overestimation factors to 3.75,1.52 and 1.44 for PM 2.5,PM 10 and TSP,*** reductions in model error may be obtained from use of additional observations and refinement of dispersive correction *** generally,the correction permits the validated adjustment and application of pre-existing models for risk assessment and development of remediation *** same approach may also be applied to improve simulations of other air pollutants and environmental conditions of concern.

关键词： Air quality Particulate matter Air dispersion modelling Cotton gin

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The complexity of sediment recycling as revealed by common Pb isotopes in K-feldspar

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Geoscience Frontiers 2018年第5期9卷 1515-1527页

作者： Simon P.johnson Christopher L.Kirkland noreen.j.evans Brad j.McDonald Huntly n.Cutten Geological Survey of Western Australia Mineral House100 Plain StreetEast PerthWestern Australia6004Australia Centre for Exploration Targeting-Curtin node The Institute for Geoscience ResearchDepartment of Applied GeologyWestern Australian School of MinesCurtin UniversityPerthWestern Australia6102Australia john de Laeter Centre The Institute for Geoscience ResearchDepartment of Applied Geology and Applied PhysicsCurtin UniversityPerthWestern Australia6102Australia

Detrital zircon U-Pb geochronology has become the gold standard in evaluating source to sink relationships in sedimentary basins. However, the physical and chemical robustness of zircon, which make it such a useful mineral for provenance studies, is also a hindrance as zircon can be recycled through numerous sedimentary basins, thus obscuring the first cycle source to sink relationship. An elegant approach to addressing this potential issue is to compare the Pb isotope composition of detrital K-feldspar, a mineral which is unlikely to survive more than one erosion-transport-deposition cycle, with that of magmatic K-feldspar from potential basement source terranes. Here we present new in situ Pb isotope data on detrital K-feldspar from two Proterozoic arkosic sandstones from Western Australia, and magmatic K-feldspar grains from potential igneous source rocks, as inferred by the age and Hf isotope composition of detrital zircon grains. The data indicate that the detrital zircon and K-feldspar grains could not have been liberated from the same source rocks, and that the zircon has most likely been recycled through older sedimentary basins. These results provide a more complete understanding of apparently simple source to sink relationships in this part of Proterozoic Western Australia.

关键词： Detrital zircon K-feldspar Pb isotopes Sediment provenance Sediment recycling

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Roles of SO_2 oxidation in new particle formation events

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journal of Environmental Sciences 2015年第4期27卷 90-101页

作者： He Meng Yujiao Zhu Greg j.evans Cheol-Heon jeong Xiaohong Yao Key Lab of Marine Environmental Science and Ecology Ministry of Education Ocean University of China Southern Ontario Centre for Atmospheric Aerosol Research University of Toronto

The oxidation of SO2 is commonly regarded as a major driver for new particle formation（nPF） in the atmosphere. In this study, we explored the connection between measured mixing ratio of SO2 and observed long-term（duration 〉 3 hr） and short-term（duration〈 1.5 hr） nPF events at a semi-urban site in Toronto. Apparent nPF rates（j30） showed a moderate correlation with the concentration of sulfuric acid（[H2SO4]） calculated from the measured mixing ratio of SO2 in long-term nPF events and some short-term nPF events（Category I）（R^2= 0.66）. The exponent in the fitting line of j30~ [H2SO4]nin these events was1.6. It was also found that SO2 mixing ratios varied a lot during long-term nPF events,leading to a significant variation of new particle counts. In the SO2-unexplained short-term nPF events（Category II）, analysis showed that new particles were formed aloft and then mixed down to the ground level. Further calculation results showed that sulfuric acid oxidized from SO2 probably made a negligible contribution to the growth of 〉 10 nm new particles.

关键词： nucleation Particle growth Sulfuric acid Photochemical oxidation SO2

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Mobilization of Cu in the continental lower crust:A perspective from Cu isotopes

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Geoscience Frontiers 2023年第5期14卷 17-38页

作者： Chen-Hao Luo Rui Wang Yun Zhao jian Huang noreen.j.evans State Key Laboratory of Geological Processes and Mineral Resources and Institute of Earth SciencesChina University of GeosciencesBeijing 100083China State Key Laboratory for Mineral Deposits Research School of Earth Sciences and EngineeringNanjing UniversityNanjingChina SinoProbe Laboratory of Chinese Academy of Geological Sciences BeijingChina State Key Laboratory of Geological Processes and Mineral Resources School of Earth Sciences and ResourcesChina University of GeosciencesBeijing 100083China CAS Key Laboratory of Crust-Mantle Materials and Environments School of Earth and Space SciencesUniversity of Science and Technology of ChinaHefei 230026China john de Laeter Centre Curtin UniversityGPO Box U1987PerthWA 6845Australia

Recent studies have shown that Cu-rich sulfide accumulates in the lower continental crust and serves as a critical reservoir to balance Cu depletion in the upper *** of Cu in the lower crust is also assumed to be a major metal source for non-arc setting porphyry Cu *** test this hypothesis and further explore the behavior of Cu in the lower crust,we analyzed the elemental and Cu isotopic compositions of lower crustal rocks from different geological *** collected samples include hornblendites from the Kohistan arc,granulite xenoliths and hornblendites from the Gangdese arc,hornblendites and gabbros from the Laiyuan complex in the north China Craton,and hornblendite xenoliths from the western margin of the Yangtze *** lower crustal rocks have experienced varying degrees of primary or secondary sulfide accumulation,with significantly varied Cu contents(11.2 to 145 ppm)andδδ^(65)(1.05‰to 1.40‰).Petrography and geochemistry reveal varying degrees of metasomatism and fluid interaction in these rocks,and based on this,they can be further divided into three groups:Group I includes the Gangdese granulites and Yunnan hornblendites,which perhaps experienced significant *** suite of rocks shows enrichment ofδ^(65)(dδ^(65)=0.01‰to 1.40‰),positively correlated with metasomatism(dδ^(65)***/Pb).We suggest the secondary sulfides which transformed from sulfates during the interaction between lower crust and arc magma are dominant in these rocks,so the feature of heavy isotope enrichment is *** II includes Laiyuan hornblendites and gabbros,derived from the same parental magma and emplaced at different depths(hornblendites,23.3–28.1 km;gabbros 8.4–11.1 km).The Cu isotopic compositions are strongly fractionated between these two kinds of rocks,with low dδ^(65)in the hornblendites(0.00‰to 0.28‰)and highly polarized dδ^(65)in the gabbros(1.05‰to 0.81‰).Geochemical indicators and mineral assemblages reveal that fluid intera

关键词： Cu isotope of lower continental crust Cu mobilization Metasomatism Fluid interaction Partial melting

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Late Palaeogene emplacement and late neogene-Quaternary exhumation of the Kuril island-arc root (Kunashir island) constrained by multi-method thermochronometry

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Geoscience Frontiers 2016年第2期7卷 211-220页

作者： j.De Grave F.I.Zhimulev S.Glorie G.V.Kuznetsov n.evans F.Vanhaecke B.McInnes Department of Geology and Soil Science Mineralogy and Petrology Research Unit Ghent University Ghent Belgium Institute of Geology and Mineralogy Siberian Branch Russian Academy of Sciences Novosibirsk Russia Tectonics Resources and Exploration (TraX) Department of Earth Sciences School of Physical Sciences University of Adelaide Adelaide Australia john De Laeter Center for Isotope Research Applied Geology/Applied Physics Curtin University Perth Australia Department of Analytical Chemistry Atomic and Mass Spectrometry Research Unit Ghent University Ghent Belgium

The Kuril islands constitute a volcanic island arc-trench system, stretching from eastern Hokkaido （japan） to Kamchatka （Russia） along the northwestern Pacific subduction system, The current arc consists of several volcanic islands mainly with neogene basement and capped by several, predominantly andesitic, active subduction stratovolcanoes, Kunashir Island is the southwestern-most island of the arc, just off the Hokkaido coast and represents the study area in this paper. The island is composed of a Lower Complex of mainly late Miocene to Pliocene volcanic rocks, covered by an Upper Complex of younger （basaltic） andesitic lava flows and tuffs on which currently four active volcanic edifices are built. In the Lower Complex sub-volcanic and deeper-seated intrusives of the so-called Prasolov and Dokuchaev magmatic complexes are found, More differentiated, tonalitic-granodioritic rocks were collected from these small intrusive bodies. An early Oligocene zircon LA-ICP-MS U/Pb age of 31 Ma for the Prasolov Complex was obtained, showing that the basement of Kunashir Island is older than previously thought. Thermochronometry （apatite fission-track and U-Th-Sm/He and zircon U-ThjHe analyses） further shows that the magmatic basement of the island was rapidly exhumed in the Pleistocene to present levels in a differential pattern, with He-ages ranging from 1.9 to 0.8 Ma. It is shown that the northern section of the island was hereby exhumed more intensely.

关键词： Kuril island arc Kunashir island northwest pacific Thermochronometry Zircon U-Pb dating

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Review： Sugar beets as a substitute for grain for lactating dairy cattle

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journal of Animal Science and Biotechnology 2017年第3期8卷 539-548页

作者： Essi evans Ulrike Messerschmidt Technical Advisory Services Inc 64 Scugog St Bowmanville ON L1C3J Canada KWS SAAT SE Grimsehlstr. 31 P.O. Box 1463D-37555 Einbeck Germany

Dairy cows are customarily given grains and highly digestible byproduct ingredients as additions to forage to support milk production. In many parts of the world growing seasons are short, and the grain crops that can be grown may not provide adequate yields. Sugar beets, on the other hand are relatively hardy, and dry matter yields surpass the yields of most grain crops. There are however, perceptions that beets may not be suitable as a feed ingredient due to the fact that the storage form of carbohydrate is sugar rather than starch. With little analytical support, sugar has been rejected in many feeding programs with the view that sugar reduces rumen pH, fiber digestion and microbial yield. This review explores available facts revolving around these concerns. Information regarding the feeding of sugar beets is provided and the use of sugar beets as a partial replacement for grain is proposed.

关键词： Dairy cattle Feed beets Fodder beets Methane Sugar Sugar beets

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Synthesis of a-SnWO_4 thin-film electrodes by hydrothermal conversion from crystalline WO_3

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Chinese Chemical Letters 2015年第4期26卷 474-478页

作者： Kayla j.Pyper Taylor C.evans Bart M.Bartlett Department of Chemistry University of Michigan

Thin film electrodes of the orthorhombic form of tin tungstate （α-SnWO4） were prepared using a hydrothermal method to convert thin films of WO3 in aqueous SnCI2. The pH dependence of the growth mechanism was identified by scanning electron microscopy （SEM） and X-ray diffraction （XRD）. The XRD patterns show complete conversion of WO3（s） to SnWO4（s） at pH 1, 4, and 7. SEM images reveal a morphology change from sponge-like platelets to sharp nanowires as the pH increases from 1 to 7. The α-SnWO4 thin films were reddish brown in color, and display an indirect band gap of 1.9 eV by diffuse reflectance UV-vis spectroscopy. α-SnWO4 is therefore solar-responsive, and a chopped light linear sweep voltammogram recorded under 100 mW/cm2 AM1.5 simulated solar illumination in a pH 5 0.1 mol/L KPi buffer show a visible light response for photoelectrochemical water oxidation, producing 32 μA/cm2 at 1.23 V vs. RHE.

关键词： Alpha tin tungstateHydrothermal conversionMicrostructureHydrothermal method

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