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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

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

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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

Theoretical Analysis of the Fluctuation Theorem Applied to Electric Circuits

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Communications in Theoretical Physics 2014年第10期61卷 476-484页

作者： Charlotte F.Petersen Elmars Krausz Denis j.evans Stephen R.Williams Research School of Chemistry Australian National UniversityCanberraACT 0200Australia

We carry out a theoretical analysis of the fluctuations in the johnson–Nyquist noise in an RC electric circuit being driven by a non-ideal constant current source. Using the appropriate Langevin equation, we derive the fluctuation theorem for the system. This analysis exhibits some interesting features. Firstly, the average of the dissipation function is not necessarily just an instantaneous entropy production, i.e. the work being done on the circuit by the external power source divided by the ambient temperature. Secondly, by appropriate selection of the values for the circuit components,the transient response of the system can be made identical to the nonequilibrium steady state response. In the limit of an ideal current source, the average of the dissipation function reduces to the entropy production. Our analysis accurately reproduces published experimental results.

关键词： circuit analysis fluctuation theorems statistical machanics johnson noise

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

Isogeometric Collocation:A Mixed Displacement-Pressure Method for Nearly Incompressible Elasticity Dedicated to Professor Karl Stark Pister for his 95th birthday

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Computer Modeling in Engineering & Sciences 2021年第12期129卷 1125-1150页

作者： S.Morganti F.Fahrendorf L.De Lorenzis j.A.evans T.j.R.Hughes A.Reali Department of Electrical Computer and Biomedical EngineeringUniversita degli Studi di PaviaPavia27100Italy Institute of Applied Mechanics Technische Universitat BraunschweigBraunschweig38106Germany Department of Mechanical and Process Engineering Zurich8092Switzerland Department of Aerospace Engineering Sciences University of Colorado BoulderColorado80309USA Institute for Computational Engineering and Sciences The University of Texas at AustinTexas78712USA Department of Civil Engineering and Architecture Universita degli Studi di PaviaPavia27100Italy

We investigate primal and mixed u−p isogeometric collocation methods for application to nearly-incompressible isotropic *** primal method employs Navier’s equations in terms of the displacement unknowns,and the mixed method employs both displacement and pressure *** benchmarks for what might be considered acceptable accuracy,we employ constant-pressure Abaqus finite elements that are widely used in engineering *** a basis of comparisons,we present results for compressible *** the methods were completely satisfactory for the compressible ***,results for low-degree primal methods exhibited displacement locking and in general deteriorated in the nearly-incompressible *** results for the mixed methods behaved very well for two of the problems we studied,achieving levels of accuracy very similar to those for the compressible *** third problem,which we consider a“torture test”presented a more complex story for the mixed methods in the nearly-incompressible case.

关键词： Isogeometric analysis isogeometric collocation nearly-incompressible elasticity

Factors affecting use of ballistics gelatin in laboratory studies of bacterial contamination in projectile wounds

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Military Medical Research 2018年第4期5卷 304-313页

作者： jessica j. evans Aaron Bost Karim H. Muci-Küchler Linda C. DeVeaux Biomedical Engineering Program South Dakota School of Mines and Technology Mechanical Engineering Department South Dakota School of Mines and Technology Department of Biology New Mexico Institute of Mining and Technology

Background: Ballistics gelatin is a common tissue surrogate used in bacterial contamination models for projectile wounds. Although these studies have demonstrated that bacteria are transferred from the surface of the gelatin to the wound track by a projectile, quantifiable results have been inconsistent and not repeatable in successive ***: In this study, five areas of a typical contamination model in which bacterial recovery or survival are affected were identified for optimization. The first was a contaminated "skin" surrogate, where the novel use of vacuum filtration of a bacterial culture and buffer onto filter paper was employed. The other possibly problematic areas of the bacterial distribution model included the determination of bacterial survival when the contamination model is dried, survival in solid and molten gelatin, and the effect of high-intensity lights used for recording high-speed ***: Vacuum filtration of bacteria and buffer resulted in a consistent bacterial distribution and recovery. The use of phosphate buffer M9(pH 7) aided in neutralizing the ballistics gelatin and improving bacterial survival in solid gelatin. Additionally, the use of high-intensity lights to record high-speed video and the use of a 42℃ water bath to melt the gelatin were found to be bactericidal for gram-positive and gram-negative ***: Multiple areas of a typical contamination model in which bacterial survival may be impeded were identified, and methods were proposed to improve survival in each area. These methods may be used to optimize the results of bacterial contamination models for medical applications, such as understanding the progression of infection in penetrating wounds and to identify possible sources of contamination for forensic purposes.

关键词： Ballistics gelatin Wound Contamination Bacterial model

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

Predicting Ground Effects of Omnidirectional Antennas in Wireless Sensor Networks

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Wireless Sensor Network 2010年第12期2卷 879-890页

作者： john F. janek jeffrey j. evans 不详

Omnidirectional antennas are often used for radio frequency (RF) communication in wireless sensor networks (WSNs). Outside noise, electromagnetic interference (EMI), overloaded network traffic, large obstacles (vegetation and buildings), terrain and atmospheric composition, along with climate patterns can degrade signal quality in the form of data packet loss or reduced RF communication range. This paper explores the RF range reduction properties of a particular WSN designed to operate in agricultural crop fields to collect aggregate data composed of subsurface soil moisture and soil temperature. Our study, using simulation, anechoic and field measurements shows that the effect of antenna placement close to the ground (within 10 cm) signi?cantly changes the omnidirectional transmission pattern. We then develop and propose a prediction method that is more precise than current practices of using the Friis and Fresnel equations. Our prediction method takes into account environmental properties for RF communication range based on the height of nodes and gateways.

关键词： Omnidirectional Antenna Ground Effects Wireless Densor Networks

Flash MX、Dreamweaver MX、Fireworks MX、FreeHand MX四合一宝典

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