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俯冲带挥发分的循环不仅深刻影响着地球各圈层之间的相互作用,而且在成矿金属元素迁移-富集以及全球气候变化等重要地质和环境过程中扮演着重要的角色。近年来,金属稳定同位素示踪俯冲带挥发分循环受到了广泛关注,取得了众多进展,但大多针对单个挥发性元素开展某个特定金属同位素的示踪研究。本文根据不同金属元素的地球化学性质差异及其与多种挥发分之间的结合形式,系统归纳了金属稳定同位素在示踪俯冲带不同挥发分循环方面的特点。整体上讲,镁和锌同位素体系示踪俯冲带碳循环最为有效;锂、镁、钾、钡、钼等金属同位素体系在示踪俯冲带水(流体)循环方面则具有各自的特点;锌同位素在示踪俯冲带硫循环方面有巨大潜力;铬同位素示踪俯冲带氯循环有独特优势;铁、铬、铜等变价金属同位素体系对挥发分的氧化还原状态较为敏感,有望示踪俯冲带氧循环。这些同位素体系对理解俯冲带挥发分循环提供了全新的视角,有望成为未来地球系统科学的重要研究方向。 相似文献
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康滇池轴东侧的铅锌矿带是我国的主要铅锌矿带之一。铅同位素地球化学研究是铅锌矿床研究的重要内容之一。本文探讨了康滇地轴铅锌矿床研究中的铅同位素地球化学应用问题,指出铅同位素模式年龄不能用作矿化年龄,应当用铅同位素示踪来追踪成矿物质来源。 相似文献
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与层间氧化带有关的铀矿床的同位素—地球化学研究 总被引：2，自引：0，他引：2
本文提出了应用研究容矿岩石中铁的氧化物和氢氧化物的同位素成分的数据,来解决与层间氧化带有关的铀矿成因和预测－找矿任务的可能性;更为准确地说明了层间氧化带的形成条件,并查明了原生红色岩石和次生氧化岩石在同位素成分上的差别;证实了同位素氧的分带性与控矿后成分带性一致;测定了铀矿床的预测和找矿的同位素指标。 相似文献
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哀牢山北段金矿带铅同位素特征研究 总被引：1，自引：0，他引：1
以哀牢山北段金矿带中最大金矿田──老王寨金矿田为例，从铅同位素组成，源区特征，单阶段模式年龄，铅源初始年龄及与墨江金厂矿石铅同位素对比等五个方面，结合图表解析，论述了金矿带的铅同位索特征，指出本区铅同位素组成是基本稳定的，且主要属造山带铅。从铅同位素一个侧面证实哀牢山北段金矿带矿化从燕山期到喜马拉雅期，且以喜马拉雅期矿化为主，参加矿化物质显示多期多阶段性的特点。 相似文献
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俯冲带Li同位素地球化学: 回顾与展望 总被引：1，自引：0，他引：1
板块俯冲伴随着多种复杂的地质过程,例如流体释放、流体岩石相互作用、可能的部分熔融、元素迁移及同位素分馏等。在俯冲带壳/幔循环过程中,Li同位素(6Li和7Li)高达16%的相对质量差异使其成为研究俯冲带各种地质过程的良好示踪剂。总结了近年来有关俯冲带Li同位素的研究进展,并按照相对时间序列系统地介绍了Li同位素在俯冲各个阶段的地球化学行为,包括俯冲初始物质的Li同位素组成特征,俯冲过程中Li随流体释放及与上覆地幔楔相互作用中Li同位素的行为,富Li流体与残余板片Li的去向,最终俯冲相关产物的Li同位素组成特征以及对全球Li循环的地学意义的综合介绍。随着Li同位素测试精度的提高和各种地球化学储库Li同位素数据库的不断完善,Li同位素体系可以为俯冲过程研究提供更多信息,成为一种可靠的示踪剂。 相似文献
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内蒙古不同时代花岗岩类Nd、Pb同位素特征及其地质意义 总被引：6，自引：2，他引：4
内蒙古地区连接兴蒙造山带和华北板块两个具不同演化历史、不同性质的大地构造单元。通过分析内蒙古地区华北板块和兴蒙造山带不同位置出露的从太古宙至中生代晚期连续分布的30件花岗岩类样品的Sm Nd同位素及Pb同位素,对比了华北板块与兴蒙造山带不同时代花岗岩类的Nd、Pb同位素性质的差异,揭示了两个构造单元的演化过程。华北板块花岗岩的Nd模式年龄分布于中元古代前,从不同时代花岗岩的Nd同位素特征可见华北板块具有太古宙、晚古生代和早中生代(三叠纪)3期地壳增生历史;兴蒙造山带花岗岩的Nd模式年龄出现于古元古代之后,集中于新元古代和早古生代,其花岗岩的Nd同位素特征表明从新元古代至中生代,该区均具有较显著的地幔物质的注入。兴蒙造山带花岗岩类初始Pb同位素含量总体高于华北板块。晚古生代华北板块花岗岩类可能接受兴蒙造山带物质的直接或间接的贡献。至中生代,华北板块和兴蒙造山带作为一个统一的整体演化。 相似文献
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Anv的Shrimp离子探针分析用来测量加拿大Saskatchewen trors Hudson造山带驯鹿湖带哈得孙沉积岩中碎屑锆石的U-Pb同位素年龄。在该区,好几个岩性构造带由镁铁质到长英质变质火山岩、变质沉积岩组成,花岗质岩体成线状平行于北西侧的churdiu陆台分布(Van Schumus等人1987)。驯鹿湖带内的锆石U-Pb同位素年龄处于1.84～1.89Ga之间,而Churchiu陆台的同位素年龄在2.5～3.0Ga之上。对驯鹿湖带的火山岩、沉积岩和花岗质岩石的Nd同位素分析得出,∈_(Nd)(时间为1.9Ga)在+5到-8之间,其中较高的值来自于远离churchiu陆台以变质火山岩为主的带中;较低的值来自于与Churchiu陆台相邻的片麻岩和混合岩带内(Chaurvell等人,1987),从三个带用的变质沉积岩中新测定的Nd同位素得出∈_(Nd)值在+4到-2之间,而Nd 相似文献
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郭顺 《矿物岩石地球化学通报》2021,40(5):1049-1060
俯冲带控制着地球内部和表层的物质与能量交换.硼(B)是一个质量轻的流体活动性元素.B及其同位素体系是理解俯冲-碰撞带流/熔体活动和物质循环的重要工具.本文综述了俯冲板块中各储库的硼含量和同位素组成以及主导硼分配的关键矿物.介绍了目前对大洋俯冲带弧前、弧下和弧后深度下硼循环的主要认识;简要介绍了刚起步的大陆俯冲-碰撞带硼循环研究.阐述了含电气石(超)高压变质岩在俯冲带硼迁移研究中的重要性.指出今后需深化含水矿物在不同地温梯度下脱水/熔融过程中硼同位素分馏研究,加强流/熔体包裹体硼同位素分析技术及应用研究.由于B及同位素可有效区分大洋地壳和大陆地壳物质,未来将在造山带演化和地球深部物质循环研究中扮演更重要的角色. 相似文献
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S. Viswanathan K. Surya Prakash Rao B. Mahabaleswar 《Journal of the Geological Society of India》2013,82(6):621-627
Komatiites are mantle-derived ultramafic volcanic rocks. Komatiites have been discovered in several States of India, notably in Karnataka. Studies on the distribution of trace-elements in the komatiites of India are very few. This paper proposes a simple, accurate, precise, rapid, and non-destructive wavelength-dispersive x-ray fluorescence (WDXRF) spectrometric technique for determining Sc, V, Cr, Co, Ni, Cu, Zn, Rb, Sr, Y, Zr, Nb, Ba, Pb, and Th in komatiites, and discusses the accuracy, precision, limits of detection, x-ray spectral-line interferences, inter-element effects, speed, advantages, and limitations of the technique. The accuracy of the technique is excellent (within 3%) for Sc, V, Cr, Co, Ni, Cu, Zn, Rb, Sr, Zr, Nb, Ba, Pb, and Th and very good (within 4%) for Y. The precision is also excellent (within 3%) for Sc, V, Cr, Co, Ni, Cu, Zn, Rb, Sr, Y, Zr, Nb, Ba, Pb, and Th. The limits of detection are: 1 ppm for Sc and V; 2 ppm for Cr, Co, and Ni; 3 ppm for Cu, Zn, Rb, and Sr; 4 ppm for Y and Zr; 6 ppm for Nb; 10 ppm for Ba; 13 ppm for Pb; and 14 ppm for Th. The time taken for determining Sc, V, Cr, Co, Ni, Cu, Zn, Rb, Sr, Y, Zr, Nb, Ba, Pb, and Th in a batch of 24 samples of komatiites, for a replication of four analyses per sample, by one operator, using a manual WDXRF spectrometer, is only 60 hours. 相似文献
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E. M. Prasolov S. A. Sergeev B. V. Belyatsky E. S. Bogomolov K. A. Gruzdov I. N. Kapitonov R. Sh. Krymsky V. O. Khalenev 《Geochemistry International》2018,56(1):46-64
This paper reports the first results of a study of 11 isotope systems (3He/4He, 40Ar/36Ar, 34S/32S, 65Cu/63Cu, 62Ni/60Ni, 87Sr/86Sr, 143Nd/144Nd, 206–208Pb/204Pb, Hf–Nd, U–Pb, and Re–Os) in the rocks and ores of the Cu–Ni–PGE deposits of the Norilsk ore district. Almost all the results were obtained at the Center of Isotopic Research of the Karpinskii All-Russia Research Institute of Geology. The use of a number of independent genetic isotopic signatures and comprehensive isotopic knowledge provided a methodic basis for the interpretation of approximately 5000 isotopic analyses of various elements. The presence of materials from two sources, crust and mantle, was detected in the composition of the rocks and ores. The contribution of the crustal source is especially significant in the paleofluids (gas–liquid microinclusions) of the ore-forming medium. Crustal solutions were probably a transport medium during ore formation. Air argon is dominant in the ores, which indicates a connection between the paleofluids and the atmosphere. This suggests intense groundwater circulation during the crystallization of ore minerals. The age of the rocks and ores of the Norilsk deposits was determined. The stage of orebody formation is restricted to a narrow age interval of 250 ± 10 Ma. An isotopic criterion was proposed for the ore-bearing potential of mafic intrusions in the Norilsk–Taimyr region. It includes several interrelated isotopic ratios of various elements: He, Ar, S, and others. 相似文献
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奥地利安东帕有限公司 《岩矿测试》2009,28(3):306-306
最新的流行病学研究表明,空气中较高浓度的悬浮细颗粒可能对人类的健康有不利的影响。根据该项研究显示,由于心脏病、慢性呼吸问题和肺功能指标恶化而导致死亡率的升高与细尘粒子有关。这些研究结果已经促使欧盟于1999年4月出台了限制空气中二氧化硫、二氧化氮、氧化氮、铅和颗粒物含量的法案(1999/30/EC),对各项指标包括对可吸入PM10颗粒的浓度提出了新的限制性指标。PM10颗粒是指可以通过预分级器分离采集的气体动力学直径小于10μm的细颗粒。目前研究的兴趣重点逐步偏向PM2.5这些更细微颗粒物,PM2.5这种颗粒物对健康有明显的不利影响。在欧盟指令2008/50/EC中,对PM10和PM2.5都提 相似文献
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Mining induced subsidence can significantly affect mining costs where major surface facilities and natural environment need to be protected. Overburden grout injection is a technology used to control coal mine subsidence by injecting the mine waste material extracted from the coal back into the inter-burden rock during longwall mining. The flowing slurry is here categorised as a nonlinear viscous cohesive (Bingham plastic) fluid. During longwall mining the grout slurry is pumped into the separated beds of the rock mass through a central vertical borehole, which is drilled deep into the inter-burden rock strata above the coal seam. However, a blockage can occur in the injection system when the slurry velocity falls below a certain critical threshold velocity, indicating a material phase change from cohesive-viscous to cohesive-frictional. In situ field injection tests through boreholes have been simulated at a smaller scale at the CSIRO laboratory in Brisbane by pumping the slurry through a radial disk (gap = 4 mm) from its centre. Laboratory experiments indicate a general, nonlinear, cohesive, viscous, frictional model for shear behaviour of the slurry, in which the material shear parameters are functions of the disk radial distance. Complete dimensional and dimensionless analytical solutions have been developed based on an approach related to Bingham–Herschel–Bulkley fluid mechanics. The derived formulae include relations for minimum pump pressure, local pressure and pressure gradient, wall shear stress, volume rate, velocity and velocity gradient. The theoretical results match the experimental measurements. The experiments covered slurries with maximum particle sizes of 0.5 to 2 mm with about 50% being larger than 100 µm. The viscosities at the various solids concentrations were measured with a standard torsion viscometer. This study differs from the previous research in several distinct aspects, namely, consideration of the variable shear parameters rather than fixed values, inclusion of total nonlinear behaviour, and implementation of a friction function to mimic behaviour of the deposited and consolidating stiff slurry, which can cause a significant pressure rise as a result of the increased shear resistance. 相似文献
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《Applied Geochemistry》2001,16(2):137-159
Five hundred and ninety-eight samples of terrestrial moss (Hylocomium splendens and Pleurozium schreberi) collected from a 188,000 km2 area of the central Barents region (NE Norway, N Finland, NW Russia) were analysed by ICP-AES and ICP-MS. Analytical results for Al, B, Ba, Ca, K, La, Mg, Mn, Na, P, Rb, Si, Sr, Th, U and Y concentrations are reported here. Graphical methods of data analysis, such as geochemical maps, cumulative frequency diagrams, boxplots and scatterplots, are used to interpret the origin of the patterns for these elements. None of the elements reported here are emitted in significant amounts from the smelting industry on the Kola Peninsula. Despite the conventional view that moss chemistry reflects atmospheric element input, the nature of the underlying mineral substrate (regolith or bedrock) is found to have a considerable influence on moss composition for several elements. This influence of the chemistry of the mineral substrate can take place in a variety of ways. (1) It can be completely natural, reflecting the ability of higher plants to take up elements from deep soil horizons and shed them with litterfall onto the surface. (2) It can result from naturally increased soil dust input where vegetation is scarce due to harsh climatic conditions for instance. Alternatively, substrate influence can be enhanced by human activity, such as open-cast mining, creation of ‘technogenic deserts’, or handling, transport and storage of ore and ore products, all of which magnify the natural elemental flux from bedrock to ground vegetation. Seaspray is another natural process affecting moss composition in the area (Mg, Na), and this is most visible in the Norwegian part of the study area. Presence or absence of some plant species, e.g., lichens, seems to influence moss chemistry. This is shown by the low concentrations of B or K in moss on the Finnish and Norwegian side of the (fenced) border with Russia, contrasting with high concentrations on the other side (intensive reindeer husbandry west of the border has selectively depleted the lichen population). 相似文献
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Marta L. PATINO-DOUCE Alberto PATINO-DOUCE Mazhar QAYYUM Roger L. NIELSEN 《Geostandards and Geoanalytical Research》1994,18(2):195-198
We have developed a set of four synthetic standards for the rare earth and high field strength elements designed for use in the determination of those elements in silicates. The base material is a glass nominally at the eutectic of the MgO-Al2 O3 -SiO2 ternary system. The nominal doping level was 2 wt% of the elements as oxides. To avoid problems associated with peak interference, the elements were doped in four separate glasses. 相似文献
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Alexander E. C. Broberg J. S. Kehren A. R. Graziani M. M. Turri W. L. 《Environmental Geology》1993,22(4):353-361
Bellechester, Minnesota, is a small community of approximately 155 residents located on the county line between Goodhue and Wabasha counties in southeast Minnesota's karst region. Bellechester is served by a 21-year-old wastewater treatment facility (WWTF) consisting of three waste-stabilization ponds. On 28 April 1992 six sinkholes were discovered to have drained cell 2 of the WWTF resulting in the loss of approximately 8.7×106 1 of partially treated effluent and about 600 m3 of soil into previously undetected subsurface voids of unknown dimensions. In the week following the collapse, approximately 200 water wells located within a 5-km radius of the WWTF were sampled in an after-the-fact, emergency sampling program. Twelve samples with elevated fecal coliform levels, 18 samples with nitrate-nitrogen greater than the 10 mg/1 standard, and no samples with elevated chlorides were found. However, the elevated levels could not be unambiguously attributed to the WWTF collapse. This is the third WWTF to fail by sinkhole collapse in southeast Minnesota since 1974. All three collapsed lagoons have been located in similar geomorphic and stratigraphic settings. However, at least two lagoons have collapsed in the adjacent area in northeast Iowa, and these lagoons are located at different stratigraphic positions. Twenty-two WWTFs constructed in southeast Minnesota's karst region in the last 25 years have been identified as subject to potential sinkhole collapse. An unknown but significant number of manure storage lagoons, flood control structures, etc., have also been constructed in the karst region and are at risk. Public agencies are beginning to develop plans to deal with the risk associated with existing and future waste lagoons in this environment. The critical hydrogeologic parameters that can be used to prioritize the risk of collapse at existing facilities include: (1) the lithology of the first bedrock beneath each lagoon, (2) the thickness of surficial materials between the lagoon and the bedrock surface, (3) the presence and construction of liners (seepage rate), and (4) the proximity to existing sinkholes. 相似文献