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1.
孢粉记录揭示的2万年以来若尔盖地区的气候变化 总被引：9，自引：1，他引：9
若尔盖黑河牧场ＤＣ剖面的孢粉记录表明，末次冰期晚阶段若尔盖原高的气候表现为不稳定性，即冷暖变化频繁，其基本变化与全球一致，相对暖的阶段发生在２０－１８ＫａＢＰ，１６－１５ＫａＢＰ和１３－１１．２ＫａＢＰ；相对冷的阶段在１８－１６ＫａＢＰ，１５－１４ＫａＢＰ和１１．２－１０．２ＫａＢＰ。其中末次冰期最盛期发生于１８－１６ＫａＢＰ；１１．２－１０．２ＫａＢＰ的降温可对应于ＹｏｕｎｇｅｒＤｒｙａｓ事件。 相似文献
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甘孜黄土与青藏高原冰冻圈演化 总被引：8，自引：1，他引：8
逐样系统交变退磁磁性测量表明，８６ｍ的甘孜黄土剖面形成于约８１．８４×１０＾４ａ ＢＰ前。剖面中黄土石英砂类型分析揭示出至少约８１．８４×１０＾４ａ ＢＰ以前，高原已进入冰冻圈，并且很快于约７６×１０＾４ ａＢＰ前冰川规模达到最大，并持续至约５３×１０＾４ｑａ ＢＰ前，倒数第二次冰川规模次之，然后冰川规模明显减少。 相似文献
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青藏高原晚新生代磁性地层研究 总被引：26，自引：5，他引：26
本文较详细的论述了青藏高原晚新生代晚期的２０多个地层剖面或钻孔的磁性地层极性期,得出了一批地层年代数据。如昆仑山口羌塘组为３．１ＭａＢＰ－０．６５ＭａＢＰ,在该组中发现的三趾马化石为２．０８ＭａＢＰ,定日县贡巴组为２．３ＭａＢＰ－１．９ＭａＢＰ;札达盆地札达组和香孜组为６．１５ＭａＢＰ－３．４ＭａＢＰ,３．４ＭａＢＰ－１．２５ＭａＢＰ;理塘甲洼组为１．２４ＭａＢＰ－０．４３ＭａＢＰ,还得出吉隆三跖 相似文献
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对南海北部陆坡Ｖ３６－０６－３柱状样上部进行高分辨率地层学研究、浮游有孔虫和稳定同位素分析，并运用转换函数法和加权平均法求取约１５０００—７０００ａＢ．Ｐ．的末次冰消期中古环境参数的变化。结果发现约１０５００—７９００ａＢ．Ｐ．期间有一次强烈的古气候回返事件，与新仙女木期相对应，但持续时间较长。在此期间，冬季平均表层水温下降２．７℃，溶解氧与磷酸盐磷含量增高，古盐度与碳酸盐溶解度略有上升，黑潮水的影响大为降低，推测系海面上升过程中爪哇海海水进入南海所致。 相似文献
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对南海北部陆坡Ｖ３６－０６－３柱状样上部进行高分辨率地层学研究、浮游有孔虫和稳定同位素分析，并运用转换函数法和加权平均法求取约１５０００—７０００ａＢ．Ｐ．的末次冰消期中古环境参数的变化。结果发现约１０５００—７９００ａＢ．Ｐ．期间有一次强烈的古气候回返事件，与新仙女木期相对应，但持续时间较长。在此期间，冬季平均表层水温下降２．７℃，溶解氧与磷酸盐磷含量增高，古盐度与碳酸盐溶解度略有上升，黑潮水的影响大为降低，推测系海面上升过程中爪哇海海水进入南海所致。 相似文献
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大柴达木盐湖硼同位素地球化学研究 总被引：11，自引：0，他引：11
以测定Ｃｓ２ＢＯ２＾＋离子的热电离质谱法，用ＶＧ－３５４型质谱计测定了大柴达木盐湖卤水及其外围水系的硼同位素组成。其卤水的δ＾１１Ｂ值为＋４．９６‰－＋９．１１‰，外围水系的δ＾１１Ｂ值为－３．８５％￣－４２．６８‰。同时也测定了其湖底沉积物，外围碳酸盐泉华和硼酸盐的硼同位素组成，它们的δ＾１１Ｂ值分别为－１７．７８‰￣＋２．５６‰、－３１．９７‰￣＋０．１７‰和－１１．８７‰￣－９．５９‰。这些 相似文献
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珠江口沉积柱样^210Pb法年龄测定结果及其环境地球化学意义 总被引：22，自引：3，他引：19
提供了珠江河口及河道１０个沉积柱＾２１０Ｐｂ法的ＣＦ模式（稳恒放射性通量模式）和ＣＡ模式（稳恒初始放射性模式）的年龄测定结果,并据此讨论珠江三角洲近百年来沉积环境的演化,研究结果表明,西江河道和珠江广州河道１９８０年以前沉积速率为０．５－１．０ｃｍ／ａ．１９８０年以后沉积速率增长加快,９０年代达到４－６ｃｍ／ａ,沉积通量为４－６ｇ／（ｃｍ＾２．ａ）河口沉积速率逐年增长趋势,但一般比河道柱样小得多, 相似文献
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日本本州岛中部的远野砂岩型铀矿区地层由中新统下部的湖相沉积岩（１８￣２２Ｍａ）和上部的海相（１５￣１６Ｍａ）沉积岩组成。方解石和黄铁矿是该地层中的主要成岩蚀变产物。湖相和海相的方解石和黄铁矿的特征差别很大。湖相沉积物中方解石的δ＾１３Ｃ值低（－１９‰￣－６‰ＰＤＢ），而海相地层中的δ＾１３Ｃ值高（－１１‰￣＋３‰）。这意味着海相碳酸盐在上部海相沉积岩上所起的作用较大，下部湖相地层中方解石的碳既来源 相似文献
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本文将珠江三角洲晚更新世以来的演化分为前三角洲(约４００００—３２５００ａＢ．Ｐ．)、老三角洲(３２５００—７５００ａＢ．Ｐ．)和新三角洲(７５００ａＢ．Ｐ．—现在)三个阶段，并在此基础上探讨珠江三角洲沉积－古地理的变迁。研究结果表明，在前三角洲阶段，珠江三角洲为内陆环境，五条大河在中山三角一带汇合，然后向南东入海。磨刀门西江水道形成于第二阶段的３００００—２００００。Ｂ．Ｐ．；狮子洋、珠江和银洲湖等水道则是全新世才发展起来的。三角洲发生过两次海侵。第一次大约开始于３２５００ａＢ．Ｐ．，第二次大约开始于７５００ａＢ．Ｐ．。两次海侵形成了新、老两套三角洲沉积。 相似文献
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本文将珠江三角洲晚更新世以来的演化分为前三角洲（约４００００—３２５００ａＢ．Ｐ．）、老三角洲（３２５００—７５００ａＢ．Ｐ．）和新三角洲（７５００ａＢ．Ｐ．—现在）三个阶段，并在此基础上探讨珠江三角洲沉积－古地理的变迁。研究结果表明，在前三角洲阶段，珠江三角洲为内陆环境，五条大河在中山三角一带汇合，然后向南东入海。磨刀门西江水道形成于第二阶段的３００００—２００００。Ｂ．Ｐ．；狮子洋、珠江和银洲湖等水道则是全新世才发展起来的。三角洲发生过两次海侵。第一次大约开始于３２５００ａＢ．Ｐ．，第二次大约开始于７５００ａＢ．Ｐ．。两次海侵形成了新、老两套三角洲沉积。 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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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
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岩石密度和超高压岩石折返速率 总被引：1，自引：3，他引：1
在常温常压条件下对中国大陆科学钻CCSD主孔100-3000米岩心样品进行了密度测量,建立了密度连续剖面,并界定了不同超高压岩石的密度值。通过对比高温高压物性实验资料,岩石密度随着退变程度增强而降低,榴辉岩密度变化序列为3.52g/cm3→3.49g/cm3→3.07g/cm3→2.93g/cm3。超高压长英质岩石密度变化序列为3.00g/cm→2.80g/cm3→2.65g/cm3。上述实验资料是讨论不同折返阶段岩石所受浮力的基础,为研究折返速率大小提供了基本参数。本文通过折返板块运动平衡时,上浮力与粘滞力平衡这一关系式,定量研究了大陆俯冲板块的折返速率,认为密度差产生上浮力从而引起折返,温度对板块折返速率的影响最为显著;密度差大小、折返角度、折返板块大小对折返速率也有直接的影响。定量模拟分析表明,在温度高于850℃时,板块的折返速率可以超过100mm/a;当温度降至700℃时,折返速率则低于1.5mm/a。作者认为在折返早期,温度较高,板块快速折返至60-70km榴辉岩相深度;随着传导散热,温度降低,板块以较慢的速率折返至中下地壳。折返速率的估算表明,浮力是板块折返第一阶段(从>100km深部折返至<40km的中下地壳)的主要驱动力。 相似文献
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滇东南锡、银、铅、锌多金属矿床主要分布在个旧、白牛厂、都龙3个矿区,而滇东南较大的3个花岗岩体又分别出露在3个矿区或附近.花岗岩体均形成于燕山晚期,岩石化学、矿物成分相似,富含锡、银、铅、锌、钨、铜等成矿元素.矿床主金属元素组合与岩体之间的距离由远而近出现由锡、钨、(铍、铌、钽)→锡、钨、(铁)、铜、铟→锡、铅、锌、银、铟、(锑)有规律的变化.花岗岩浆是成矿物质来源和成矿热源.岩浆侵入初期使上覆地层隆起产生背斜(凹陷部位成向斜);同时使地层产生一系列裂隙、压性断层或层间断裂;岩浆侵入晚期,这些断层再次活动,表现为张性,岩浆产生的含矿热液沿由其活动所造成的断裂迁移、充填、交代、沉淀而形成矿床. 相似文献