检索结果-南通市图书馆

Geology and Lead-Sulphur Isotope Compositions of the Tongyu Volcanic-Hosted Massive Sulphide Copper Deposit in the Western Part of the North Qinling Orogen, China

在线全文

学校读者我要写书评

暂无评论

Acta Geologica Sinica(English Edition) 2017年第5期91卷 1767-1777页

作者： GONG Hujun ZHU Laimin LI Ben XIONG Xiao DING Lele State Key Laboratory of Continental Dynamics Department of Geology Northwest University centre for Exploration Targeting ARC Centre of Excellence for Core to Crust Fluid Systems (CCFS)School of Earth and Environment The University of Western Australia

The Tongyu copper deposit, located in the western part of the North Qinling Orogen, China, is one of several volcanic-hosted massive sulphide（VHMS） deposits with industrial value and is also a typical example of mineralization related to the subduction and metallogenesis during the Caledonian orogeny. We conducted systematic lead-sulphur isotope geochemical analyses of the Tongyu deposit to understand the possible ore-forming material sources and tectonic settings. Twenty-six sulphide samples yielded clustered δ^34SCDT values of 1.13‰-3.36‰, average 2.22‰, and show a tower-type distribution,implying that the sulphur of the Tongyu copper deposit mainly originated from a mantle source. The Pb isotope compositions of sulphides（^206Pb/^204Pb = 17.59225-18.56354, average 18.32020; ^207Pb/^204Pb =15.51770-15.69381, average 15.66217; ^208Pb/^204Pb= 37.99969-39.06953, average 38.52722） are close to the values of the volcanic host rocks（^206Pb/^204PbPb= 18.10678-18.26293, average 18.21158; ^207Pb/^204PbPb =15.63196-15.68188, average 15.65345; ^208Pb/^204PbPb= 38.43676-38.56360, average 38.49171）, thus consistent with the Pb in ores and volcanic host rocks having been derived from a common source that was island-arc Pb related to oceanic crust subduction. The northward subduction of the Palaeo-Qinling oceanic crust triggered dehydration of the slab, which generated a large amount of high-oxygen-fugacity aqueous hydrothermal fluid. The fluid rose into the mantle wedge, activated and extracted metallogenic material and promoted partial melting of the mantle wedge. The magma and ore-forming fluid welled up and precipitated, finally forming the Tongyu VHMS copper deposit.

关键词： VHMS-type copper deposit ore-forming material source S-Pb isotope island arc environment

CO2 degassing and melting of metasomatized mantle lithosphere during rifting-Numerical study

在线全文

学校读者我要写书评

暂无评论

Geoscience Frontiers 2019年第4期10卷 1409-1420页

作者： Weronika Gorczyk Christopher M. Gonzalez University of Western Australia Centre for Exploration TargetingSchool of Earth SciencesARC Centre of Excellence for Core to Crust Fluid SystemsPerthWestern AustraliaAustralia School of Earth Atmosphere and EnvironmentMonash University ClaytonMelbourneVICAustralia

:Reactivation of metasomatized mantle lithosphere may occur during continental extension,which is an important component of plate *** lower most part of the metasomatized domains in the subcontinental mantle lithosphere can be locally enriched in ***,partial melting of these metasomatized domains may play a crucial role in the global carbon ***,little is known about this process and up until now few numerical constraints are *** we address this knowledge gap and use a 2-D high resolution petrological-thermomechanical model to assess lithospheric ***2 degassing and *** test 4 lithospheric thicknesses:90,110,130 and 200 km with a 10 km thick metasomatized layer at the base using CO2 of 2 wt.%in the bulk *** carbonate enriched layer is stable below^3 GPa(>110 km)for a temperature of 1300℃;therefore,we only observe degassing patterns for lithospheric models that are 130 km and 200 km *** metasomatized layer for the 130 km thick lithosphere mostly comprises carbonatite melting,whereas in the 200 km thick scenario propagation of melt development from kimberlites to carbonatites occurs as the metasomatic mantle is exhumed during *** numerical models fit well into natural rifting zones of the European Cenozoic Rift System for young(shallow)and of the North Atlantic Rift for old(thick)lithosphere.

关键词： Rifting Mantle CO2 degassing Carbonate melting

Magnetopause properties at the dusk magnetospheric flank from global magnetohydrodynamic simulations,the kinetic Vlasov equilibrium,and in situ observations--Potential implications for SMILE

在线全文

学校读者我要写书评

暂无评论

Earth and Planetary Physics 2024年第1期8卷 222-233页

作者： Marius Echim Costel Munteanu Gabriel Voitcu Eliza Teodorescu Institute of Space Science Măgurele 077125Romania Royal Belgian Institute for Space Aeronomy 1180 BrusselsBelgium Solar-Terrestrial centre of excellence(STCE) 1180 BrusselsBelgium

We derived the properties of the terrestrial magnetopause(MP)from two modeling approaches,one global–fluid,the other local–kinetic,and compared the results with data collected in situ by the Magnetospheric Multiscale 2(MMS2)*** used global magnetohydrodynamic(MHD)simulations of the Earth’s magnetosphere(publicly available from the NASA-CCMC[National Aeronautics and Space Administration–Community Coordinated Modeling Center])and local Vlasov equilibrium models(based on kinetic models for tangential discontinuities)to extract spatial profiles of the plasma and field variables at the Earth’s *** global MHD simulations used initial solar wind conditions extracted from the OMNI database at the time epoch when the MMS2 observes the *** kinetic Vlasov model used asymptotic boundary conditions derived from the same in situ MMS measurements upstream or downstream of the *** global MHD simulations provide a three-dimensional image of the magnetosphere at the time when the MMS2 crosses the *** Vlasov model provides a one-dimensional local view of the MP derived from first principles of kinetic *** MMS2 experimental data also serve as a reference for comparing and validating the numerical simulations and *** found that the MP transition layer formed in global MHD simulations was generally localized closer to the Earth(roughly by one Earth radius)from the position of the real MP observed by the *** also found that the global MHD simulations overestimated the thickness of the MP transition by one order of magnitude for three analyzed variables:magnetic field,density,and tangential *** MP thickness derived from the local Vlasov equilibrium was consistent with observations for all three of these *** overestimation of density in the Vlasov equilibrium was reduced compared with the global MHD *** discuss our results in the context of future SMILE(Solar wind Magnetosphere Ionosphere Link Explorer)campaigns for observing

关键词： magnetopause magnetohydrodynamic numerical simulations Vlasov equilibrium Magnetospheric Multiscale observations

Variation in mantle lithology and composition beneath the Ngao Bilta volcano,Adamawa Massif,Cameroon volcanic line,West-central Africa

在线全文

学校读者我要写书评

暂无评论

Geoscience Frontiers 2020年第2期11卷 665-677页

作者： Robert Temdjim Merlin Patrick Njombie Wagsong Arnold Julien Nzakou Tsepeng Stephen Foley Department of Earth Sciences Faculty of SciencesUniversity of Yaounde IP.O.Box.812 YaoundeCameroon Department of Earth and Planetary Sciences and arc centre of excellence for core to crust fluid systems Macquarie UniversityNorth RydeNSW2109Australia

Mantle peridotites entrained as xenoliths in the lavas of Ngao Bilta in the eastern branch of the continental Cameroon Line were examined to constrain mantle processes and the origin and nature of melts that have modified the upper mantle beneath the Cameroon *** xenoliths consist mainly of lherzolite with subordinate harzburgite and *** commonly contain olivine,orthopyroxene,clinopyroxene and spinel although the dunite is *** is an essential constituent in the *** chemistry differs between the three types of peridotite:olivines have usual mantle-like Mg#of around 90 in lherzolites,but follow a trend of decreasing Mg#(to 82)and NiO(to 0.06 wt.%)that is continuous in the *** also contain orthopyroxenes and/or clinopyroxenes with low-Mg#,indicating a reaction that removes Opx and introduces Cpx,olivine,amphibole and *** is attributed to reaction with a silica-undersaturated silicate melt such as nephelinite or basanite,which originated as a low-degree melt from a depleted source as indicated by low Al2O3 and Na2O in Cpx and high Na2O/K2O in *** estimates place the xenoliths at pressures of 11–15 kbar(35–50 km)and temperatures of 863–957C,along a dynamic rift geotherm and shallower than the region where carbonate melts may *** melt/rock reactions exhibited by the Ngao Bilta xenoliths are consistent with their peripheral position in the eastern branch of the Cameroon Volcanic Line in an area of thinned crust and lithosphere beneath the Adamawa Uplift.

关键词： Cameroon volcanic line Adamawa volcanic massif Peridotite xenoliths Partial melting Melt-rock reactions

Do Supercontinent-Superplume Cycles Control the Growth and Evolution of Continental crust?

在线全文

学校读者我要写书评

暂无评论

Journal of Earth Science 2020年第10期31卷 1142-1169页

作者： Xuan-Ce Wang Simon A.Wilde Zheng-Xiang Li Shaojie Li Linlin Li School of Earth Sciences Yunnan UniversityKunming 650500China School of Earth Science and Resources Chang'an UniversityXi'an 710054China arc centre of excellence for core to crust fluid systems(CCFS)and The Institute for Geoscience Research(TIGeR) Department of Applied GeologyCurtin UniversityPerth WA 6845Australia

The evolution of continental crust can be directly linked to the first-order supercontinent-superplume *** demonstrate that:(1)a mantle-like oxygen isotopic signature is not a diagnostic feature for distinguishing crustal addition from the reworking of pre-existing continental crust;(2)juvenile continental crust shows a wide range of whole-rock Hf isotopic compositions throughout Earth's history;and(3)detrital zircon Hf model ages cannot reliably determine the growth of continental ***,the wide use of zircon Hf model ages,based on zircon grains with mantle-like oxygen isotopes,is inappropriate for estimating the timing of continental crustal *** on an analysis of global Hf and O isotope and zircon age databases,we argue that the actual U-Pb crystallization ages of juvenile zircon grains provide the best opportunity to unravel crustal growth through time and to test its relationship with supercontinent-superplume ***,when the Hf isotopes of these juvenile grains plot within the field of juvenile continental crust,they correlate well with times of global mantle depletion as recorded by Os and He isotopes,plume activity as recorded by LIP events,and periods of crustal growth and the breakup of *** contrast,zircon grains crystallized from magmas that were produced by partial melting of pre-existing continental crust show U-Pb age peaks that correspond mainly to times of supercontinent assembly and crustal *** analysis shows the key role played by recycling of mafic crustal components in the generation of juvenile continental crust.

关键词： zircon age zircon Hf-O isotopes slab melting juvenile crust formation episodic continental crustal growth supercontinent-superplume cycles

同方期刊数据库

crustal and upper mantle structure and the deep seismogenic environment in the source regions of the Lushan earthquake and the Wenchuan earthquake

在线全文

学校读者我要写书评

暂无评论

Science China Earth Sciences 2013年第6期56卷 1158-1168页

作者： ZHENG Yong GE Can XIE ZuJun YANG YingJie XIONG Xiong HSU HouTze State Key Laboratory of Geodesy and Earth's Dynamics Chinese Academy of Sciences College of Earth Sciences University of Chinese Academy of Sciences Australian Research Council centre of excellence for core to crust fluid systems/GEMOC Department of Earth and Planetary SciencesMacquarie University

Following the M w 7.9 Wenchuan earthquake, the M w 6.6 Lushan earthquake is another devastating earthquake that struck the Longmenshan Fault Zone (LFZ) and caused severe damages. In this study, we collected continuous broadband ambient noise seismic data and earthquake event data from Chinese provincial digital seismic network, and then utilized ambient noise tomography method and receiver function method to obtain high resolution shear wave velocity structure, crustal thickness, and Poisson ratio in the earthquake source region and its surroundings. Based on the tomography images and the receiver function results, we further analyzed the deep seismogenic environment of the LFZ and its neighborhood. We reveal three main findings: (1) There is big contrast of the shear wave velocities across the LFZ. (2) Both the Lushan earthquake and the Wenchuan earthquake occurred in the regions where crustal shear wave velocity and crustal thickness change dramatically. The rupture faults and the aftershock zones are also concentrated in the areas where the lateral gradients of crustal seismic wave speed and crustal thickness change significantly, and the focal depths of the earthquakes are concentrated in the transitional depths where shear wave velocities change dramatically from laterally uniform to laterally non-uniform. (3) The Wenchuan earthquake and its aftershocks occurred in low Poisson ratio region, while the Lushan earthquake sequences are located in high Poisson ratio zone. We proposed that the effect of the dramatic lateral variation of shear wave velocity, and the gravity potential energy differences caused by the big contrast in the topography and the crustal thickness across the LFZ may constitute the seismogenic environment for the strong earthquakes in the LFZ, and the Poisson ratio difference between the rocks in the south and north segments of the Longmenshan Fault zone may explain the 5 years delay of the occurrence of the Lushan earthquake than the Wenchuan

关键词： Lushan earthquake Wenchuan earthquake receiver function ambient noise tomography deep seismogenic environ-ment

同方期刊数据库

The dominant driving force for supercontinent breakup: Plume push or subduction retreat?

在线全文

学校读者我要写书评

暂无评论

Geoscience Frontiers 2018年第4期9卷 997-1007页

作者： Nan Zhang Zhuo Dang Chuan Huang Zheng-Xiang Li Key Laboratory of Orogenic Belts and crustal Evolution School of Earth and Space SciencesPeking University Earth Dynamics Research Group ARC Center of Excellence for Core to Crust Fluid Systems(CCFS)and The Institute for Geoscience Research(TIGeR)School of Earth and Planetary SciencesCurtin University

Understanding the dominant force responsible for supercontinent breakup is crucial for establishing Earth＇s geodynamic evolution that includes supercontinent cycles and plate tectonics. Conventionally,two forces have been considered： the push by mantle plumes from the sub-continental mantle which is called the active force for breakup, and the dragging force from oceanic subduction retreat which is called the passive force for breakup. However, the relative importance of these two forces is unclear. Here we model the supercontinent breakup coupled with global mantle convection in order to address this question. Our global model features a spherical harmonic degree-2 structure, which includes a major subduction girdle and two large upwelling（superplume） systems. Based on this global mantle structure,we examine the distribution of extensional stress applied to the supercontinent by both subsupercontinent mantle upwellings and subduction retreat at the supercontinent peripheral. Our results show that：（1） at the center half of the supercontinent, plume push stress is ～3 times larger than the stress induced by subduction retreat;（2） an average hot anomaly of no higher than 50 K beneath the supercontinent can produce a push force strong enough to cause the initialization of supercontinent breakup;（3） the extensional stress induced by subduction retreat concentrates on a ～600 km wide zone on the boundary of the supercontinent, but has far less impact to the interior of the supercontinent. We therefore conclude that although circum-supercontinent subduction retreat assists supercontinent breakup, sub-supercontinent mantle upwelling is the essential force.

关键词： Supercontinent breakup Plume push Subduction retreat

Bio-analysis of Saliva Using Paper Devices and Colorimetric Assays

在线全文

学校读者我要写书评

暂无评论

Journal of Analysis and Testing 2024年第1期8卷 114-132页

作者： Adhan Narasimhan Harshil Jain Kowshika Muniandy Raja Chinnappan Naresh Kumar Mani Microfluidics Sensors and Diagnostics(μSenD)LaboratoryCentre for MicrofluidicsBiomarkersPhotoceutics&Sensors(μBioPS)Department of BiotechnologyManipal Institute of TechnologyManipal Academy of Higher EducationManipalKarnataka 576104India College of Medicine Alfaisal UniversityRiyadh 11533SaudiArabia Tissue/Organ Bioengineering&BioMEMS Lab Organ Transplant Centre of ExcellenceTransplant Research&Innovation DepartmentKing Faisal Specialist Hospital and Research CentreRiyadhSaudi Arabia

In light of the evolving nature of various diseases,time becomes a crucial factor in diagnosis and identifying the underlying causes.A point-of-care device provides a rapid diagnosis of a disease without using complex and advanced instruments,which are costly and difficult to transport.A paper-based device is a relatively frugal solution wherein the paper is used as a substratum in which the reactions are carried *** methods are non-invasive,and the sample collection is relatively *** is one such body fluid in which various biomarkers are present for numerous *** of saliva has attracted more attention recently due to its non-invasiveness and *** the discovery of clinical biomarkers from salivary analysis has the potential to revolutionize the healthcare sector by providing crucial information to monitor the health status of individuals and disease progression which enables personalized *** review provides the limitation of the traditional methods in clinical applications and highlights the significance of saliva as a non-invasive biological fluid that is a source of multiple biomarkers associated with various *** also provides insights into the different paper-based colorimetric microfluidic devices developed against salivary biomarkers in the past *** major challenges in the point-of-care application and the future prospects have been discussed as ***,we also emphasize the importance of this approach in dental disease diagnosis which is least explored and holds potential applications.

关键词： Paper-based assay Salivary analysis Non-invasive Point-of-care Body fluids Biomarkers Qualitative detection

An Elevated Perspective: Dyke-Related Fracture Networks Analysed with Uav Photogrammetry

在线全文

学校读者我要写书评

暂无评论

Acta Geologica Sinica(English Edition) 2016年第S1期90卷 54-55页

作者： Gregory DERING Steven MICKLETHWAITE Stephen J.BARNES Marco FIORENTINI Alexander CRUDEN Eric TOHVER School of Earth Sciences ARC Centre of Excellence for Core to Crust Fluid Systems University of Western Australia Mineral Resources Flagship CSIRO School of Earth Atmosphere and Environment Monash University

An abundance of data from seismic and geodetic monitoring has provided new insight into dyke propagation and emplacement *** studies show that faulting and fracturing is part of the magma

关键词： rock An Elevated Perspective Dyke-Related Fracture Networks Analysed with Uav Photogrammetry