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四川名山——丹棱地区青衣江流域的砾石层特征及水系演化 总被引：2，自引：0，他引：2
对四川名山、邛崃砾石层的砾石成分、砾度和砾向进行统计,分析了该砾石层的物质来源、古流向及阶地特征;并将其与丹棱-思蒙的砾石层进行对比,认为两砾石层是青衣江流域不同地质历史时期的产物;据古流向的分布、砾石层形成年代以及构造运动特征,讨论了青衣江水系总体上由北往南演化变迁的历史过程。 相似文献
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对共和盆地12级阶地砾石层组构进行数理统计,计算各砾石层砾度、砾态、砾向等参数,分析砾石组构特征并探讨其环境意义。结果表明：(1)各阶地砾石成分复杂,以砂岩和石英岩为主;(2)砾石形态以扁球体为主,磨圆度中等,风化程度较低;(3)砾石层形成时流水作用强弱为T8>T7>T5>T4>T10>T2>T9>T1>T3>T6>T11>T12,其中T1、T3、T4、T7、T8和T11为稳定河流成因,T2、T5、T6、T9、T10和T12为流水冲积成因;(4)各砾石层主要来向和古水流流向与野外观察一致,T1、T2、T5、T6和T10砾石来向与古水流流向复杂,而T3、T4、T7、T8、T9、T11和T12砾石来向与古水流流向简单。研究结果反映的环境意义虽简单,但可与阶地年代数据相结合进一步揭示各阶地形成时的气候环境特征与地面抬升状况。 相似文献
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该文通过对哀牢山构造带西侧云南省南涧地区下白垩统南新组砾岩层的砾性、砾度、砾态和砾向等的详细研究与分
析,结合盆地基岩地层特点和周边构造带的岩性组合特征,发现南新组砾岩总体上具有砾石成分复杂、分选性较差、磨圆程
度中等-较好（次圆状-圆状）、风化程度较低等特征;探讨了砾岩层本身的性质、物质来源,以及砾石沉积时盆地的水动力条
件、气候环境、古地貌特征和构造条件。认为南新组砾岩层为半干旱-干旱古气候条件下的一套冲积扇-辫状河相粗碎屑沉
积,具有快速堆积的特点;砾岩层沉积前砾石遭受了较强的物理化学作用。根据盆地基岩及周边地层岩性特点和砾石扁平面
倾向统计,砾石的主要来源是盆地内部的基底地层及其东缘的哀牢山构造带。 相似文献
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云南弥渡地区新近系三营组砾岩层砾组特征及其地质意义 总被引：1，自引：0，他引：1
通过对云南省弥渡地区哀牢山断裂带两侧的两个小型盆地内新近系三营组砾岩层砾性、砾度、砾态和砾向等的详细研究与分析,结合盆地基岩地层特点和周边构造带的岩性组合特征。对比了两盆地的砾岩层组合特征,得出两者皆为半干旱—干旱古气候条件下形成的沉积盆地,其中南涧盆地为一套冲积扇—河流相粗碎屑沉积,具有快速堆积的特点,其砾石成分组合在盆地不同位置有较多的差异,反映了其物源供应条件较复杂;而金宝山盆地虽也呈现冲积扇—辫状河—洪积相粗碎屑沉积的特性,但其砾岩组合特征表明水动力条件相对南涧盆地弱,且砾石层沉积前砾石遭受了较强的物理化学作用。就盆地基岩及周边地层岩性特点,结合砾石扁平面倾向统计,南涧盆地砾石主要来自盆地基底及周边高山,而金宝山盆地的砾石则主要来自盆地内部的基底地层及其西缘的哀牢山构造带。 相似文献
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山东诸城晚白垩世王氏群恐龙化石层碎屑锆石定年和物源示踪 总被引：2，自引：0，他引：2
山东东部诸城晚白垩世王氏群大面积、高密度集群埋藏的恐龙化石是近年研究的热点,但其沉积物源与精确沉积时限目前尚不明确。本文通过对山东诸城王氏群恐龙化石层中6个砂岩样品的碎屑锆石U-Pb定年表明,样品090414-24-D中最年轻的单颗粒锆石年龄(YSG)为77.3 Ma,应代表王氏群恐龙化石层的最大沉积时限(下限),结合前人对王氏群红土崖组的年代学研究表明,其沉积时限应老于73.5 Ma(上限),也说明赋存恐龙化石层的王氏群上部红土崖组为Campanian期沉积;碎屑锆石定年揭示物源的锆石年龄组成分布在100～130 Ma之间,6个样品的年龄主峰值多在110 Ma或120 Ma左右,与下伏的早白垩世青山群火山岩年龄主峰较为吻合。王氏群恐龙化石层砾岩的砾石成分和古水流研究显示,其中3组砾石统计表明砾岩层砾石成分主要由火山岩或火山碎屑岩组成,3组古水流数据表明,诸城地区王氏群红土崖组砾岩层的古流向以南和南东方向为主,尚有1组显示古流向为向北,表明王氏群物源主要来自盆地北侧莱阳和北西侧沂沭断裂带的青山群火山岩,其次为盆地南缘。本研究为诸城王氏群化石层沉积时限的限定和沉积物源的判断,以及胶莱盆地王氏群时期古地理格局的恢复等提供了重要的依据。 相似文献
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札达盆地是中新世9.5 Ma以来发育的新生代沉积盆地.沉积厚度、砾石成分和古流向分析显示札达盆地新生代沉积的物源主要来自盆地北部的阿伊拉日居山系.札达盆地系列样品碎屑锆石裂变径迹年龄结构显示存在两个明显的峰值年龄区间, 分别为12.6~15.3 Ma(P1峰值年龄)与19.8~22.2 Ma(P2峰值年龄).锆石裂变径迹年龄的滞后时间(lag time)与沉积时代对比分析显示, P1和P2峰值年龄为快速冷却事件的静态峰, 与北部阿伊拉日居地区基岩U-Pb年代研究揭示的热事件时间具有良好的可对比性.因此, 札达盆地碎屑裂变径迹年龄两个峰值年龄区间记录了源区阿伊拉日居的两次构造事件, 可能对应于喀喇昆仑断裂在中新世的两次强烈的构造活动.综合碎屑锆石、磷灰石裂变径迹年龄信息, 估算源区在32.6~9.5 Ma之间的平均冷却速率是15.4 ℃/Ma, 上新世末期—第四纪(3.6~1.4 Ma)之间再次发生了一次快速的隆升剥露事件.札达盆地中新生代沉积地层碎屑裂变径迹热年代学结构与喀喇昆仑断裂东南段阿伊拉日居的热事件年龄格局吻合, 从碎屑裂变径迹年代学角度揭示了造山带地区的盆山耦合过程. 相似文献
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通过对西藏阿里札达盆地河湖相地层实测剖面中的古地磁、ESR样品的测试分析,确定了札达盆地新近纪上新世—第四纪早更新世沉积地层的时间序列。测试结果表明:从剖面自下而上所做的古地磁测年数据为5.41～1.60Ma;而ESR测年数据为5.4～1.36Ma,两者大体吻合。根据古地磁、ESR测年结果,可将该套河湖相地层的时序划分为:上新世托林组(N21t)的形成时间为5.41～4.20Ma、上新世古格组(N22g)为4.20～2.57Ma、早更新世香孜组(Qp1-1x)为2.57～1.36Ma。为青藏高原新近纪上新世—第四纪早更新世地层时间序列标尺的建立,以及上新世、早更新世河湖相地层的划分与对比提供了重要依据。 相似文献
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阿拉善地块位于中亚造山带南缘,是研究中亚造山带南缘二叠纪构造背景及演化的关键地区。本研究在阿拉善地块东北缘狼山地区野外调查的基础上,对狼山地区大红山组地层进行古流向、碎屑锆石LA-ICP-MS U-Pb定年和砂岩碎屑组分分析。研究表明砾石最大扁平面倾向为SWW—NWW,指示大红山组地层沉积时的古水流的流向总体呈现自西向东,推测大红山组砾石主要来自狼山西部地区。砂岩中碎屑锆石最小年龄峰值为275 Ma和278 Ma,表明大红山组沉积时代不早于中二叠世早期。砂岩的碎屑组分分析和碎屑锆石年龄谱指示大红山组可能来自于晚古生代诺尔公—狼山弧,砾石的古流向分析和碎屑锆石年龄谱推测大红山组砾石极有可能来自于阿拉善地块前寒武纪变质基底。结合诺尔公—狼山构造带晚古生代大陆岩浆弧的存在,认为二叠系大红山组地层沉积于弧背前陆盆地的构造背景。 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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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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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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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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Mercury,arsenic, antimony,and selenium contents of sediment from the Kuskokwim River,Bethel, Alaska,USA 总被引：1，自引：0，他引：1
The Kuskokwim River at Bethel, Alaska, drains a major mercury-antimony metallogenic province in its upper reaches and tributaries. Bethel (population 4000) is situated on the Kuskokwim floodplain and also draws its water supply from wells located in river-deposited sediment. A boring through overbank and floodplain sediment has provided material to establish a baseline datum for sediment-hosted heavy metals. Mercury (total), arsenic, antimony, and selenium contents were determined; aluminum was also determined and used as normalizing factor. The contents of the heavy metals were relatively constant with depth and do not reflect any potential enrichment from upstream contaminant sources. 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
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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