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北秦岭西段奥陶纪红花铺岩体岩石地球化学特征及地质意义 总被引：1，自引：0，他引：1
红花铺岩体位于北秦岭造山带西段,侵位于奥陶纪草滩沟群之中,岩石类型主要为中细粒奥长花岗岩.岩石地球化学分析结果表明该岩体属弱过铝质钙碱性岩石系列,为I型花岗岩;轻重稀土元素分馏不明显,轻稀土元素略为富集,稀土元素球粒陨石标准化配分型式为右倾型,Eu异常不明显;主量、微量及稀土元素等相关的构造环境判别结果均显示其具典型的火山弧花岗岩特征,结合区域上与一套岛弧型火山岩(草滩沟群)共生的特点,分析红花铺岩体形成于俯冲带的岛弧环境.红花铺岩体已获得(450.5±1.8)Ma的单颗粒锆石U-Pb侵位年龄,属晚奥陶世,揭示北秦岭西段加里东期存在板块俯冲作用. 相似文献
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大兴安岭诺敏地区大地构造位置位于兴蒙造山带的东段.该区发育大量的二叠纪花岗岩类岩石,岩性主要为二长花岗岩、钾长花岗岩.岩石地球化学分析结果表明,该区岩体具有高硅,略富铝,偏碱,低镁、钠,贫钙的特征.微量元素表现出富集Rb、Th、K、Nd、Cs和亏损U、Nb、Sr、P、Ti等特点;稀土元素具有明显的轻稀土元素富集、重稀土元素亏损和明显的负Eu异常特征.轻重稀土元素分馏程度较强.岩石总体上属于高钾钙碱性系列花岗岩.地球化学特征表明其应为S型花岗岩,可能为同源的地壳物质的部分熔融作用所形成,源岩可能为变杂砂岩和变中性火山岩.根据R1-R2与Rb-（Yb+Nb）、Rb-（Yb+Ta）等微量元素判别图解,结合该区所处的构造环境推测,该区花岗岩应形成于兴安地块与松嫩地块碰撞造山过程的后碰撞阶段. 相似文献
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浙江安吉坞山关杂岩体岩相学和岩石地球化学特征及岩石成因 总被引：1，自引：0，他引：1
位于钦—杭成矿带东段北缘的浙江安吉多金属矿区发育侵位序列复杂的坞山关杂岩体及与其有关的蚀变和矿化.为了探讨区内岩浆岩与成矿的关系,在野外调查的基础上,文章对该杂岩体的岩相学、岩石地球化学开展了研究,并籍此对其成因类型、源区特征进行了探讨.坞山关杂岩体由黑云母二长花岗岩、花岗闪长岩和正长花岗岩组成,前者具富碱、高钾特征,属准铝质-钾玄岩系列,花岗闪长岩具高钾特征,属准铝质-高钾钙碱性系列,正长花岗岩具高硅、低钙、贫镁、高FeO/MgO值、富碱特征,属准铝-弱过铝质钾玄岩系列.该杂岩体的∑REE为(123.5～216.47)×10-6,稀土元素配分型式呈明显的右倾轻稀土元素富集型,Eu呈不同程度的负异常.微量元素蛛网图中,各岩石单元大离子亲石元素(尤其是Rb、Th、K)明显富集,Ba、Sr负异常明显,相对亏损高场强元素Nb、Ti、P.该杂岩体成矿元素ω(Mo)、ω(W)明显高于克拉克值,暗示其具有提供成矿物质的潜力.黑云母二长花岗岩为分异Ⅰ型花岗岩,花岗闪长岩属Ⅰ型花岗岩,正长花岗岩具有A型花岗岩的多数特征,但从杂岩体各岩石单元的成岩年龄相差不大、具地球化学亲缘性以及A型花岗岩不具高分异特征来考虑,将其归为高分异Ⅰ型花岗岩更理.La/Sm-La图解显示出,该杂岩体为平衡部分熔融作用所形成,其轻稀土元素富集、Ta-Nb、Ti、Eu、Sr、Ba负异常可能是源区为含角闪石族、金红石、斜长石作为难熔相遗留在残留物中所致. 相似文献
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永安岩体位于钦杭结合带南部,属桂东南十万大山-大容山复式岩体的一部分,其岩石类型为斑状堇青黑云花岗闪长岩。对永安岩体斑状堇青黑云花岗闪长岩进行了LA-ICPMS锆石U-Pb测年,获得其年龄为252. 8±3. 3Ma,为晚二叠世花岗岩。对永安岩体花岗岩进行的全岩地球化学分析结果表明,岩石富Al、高K,铝饱和指数A/CNK均大于1. 1,标准矿物分子刚玉均大于1%;岩石富集轻稀土元素,亏损重稀土元素,轻重稀土元素分馏明显,稀土元素的球粒陨石标准化配分曲线为轻稀土元素富集的右倾型,具弱负铕异常;岩石富集大离子亲石元素(Rb、Ba、K、Sr),亏损高场强元素(Nb、P、Ti、Ta)和Ba、Sr。花岗岩的锆石εHf(t)=-14～-8,tDM2=2. 3～1. 8 Ga。通过本文工作,结合前人关于永安岩体矿物学、全岩地球化学、Hf同位素和锆石微量元素的分析资料,认为永安岩体岩石为强过铝质S型壳源花岗岩,地幔组分没有提供成岩物质,但地幔底侵作用为成岩提供了热能,花岗岩形成于后碰撞阶段的拉张环境中。 相似文献
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西秦岭天水地区太白花岗岩体LA-ICP-MS锆石U-Pb年龄、地球化学特征及其地质意义 总被引：2，自引：1，他引：1
秦岭造山带南缘勉略构造带北侧发育有近东西向展布的印支期花岗岩带,位于甘肃徽县地区的太白岩体是该花岗岩类的一部分。LA-ICP-MS锆石U-Pb同位素年龄表明,太白岩体的形成时代为221.8Ma±1.5Ma,属于印支期晚期。主要岩石类型为灰白色—肉红色中细粒二长花岗岩和花岗闪长岩。地球化学特征表明,太白岩体属于准铝质—弱过铝质的高钾钙碱性系列;稀土元素总量ΣREE为79.0×10-6~194×10-6,稀土元素配分模式呈轻稀土元素强烈富集、重稀土元素相对亏损的右倾型,Eu负异常明显;高场强元素(HFSE)Nb、P、Ti、Y、Yb和大离子亲石元素Ba、Sr强烈亏损。太白岩体是以中基性岩石为主的壳源物质部分熔融形成的岩浆上升侵位形成的,且处于同碰撞(挤压环境)向后碰撞(伸展环境)转化阶段,为后造山期花岗岩,是扬子板块和华北板块全面碰撞导致增厚下地壳物质部分熔融的产物。 相似文献
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《四川地质学报》2022,(Z1):3-11
泉水沟北东侧花岗闪长岩体分布于泉水沟-冰水河断裂以北,是西昆仑三十里营房-大红柳滩-泉水沟构造-岩浆岩带的重要组成部分。LA-ICP-MS锆石U-Pb年代学研究结果显示岩体侵位时间为224.31±0.99Ma,形成时代为晚三叠世。地球化学分析显示岩石具有富硅、富碱、富钾,贫锰、钛的特点,铝饱和指数A/CNK=1.03-1.07,总体为过铝质高钾钙碱性S型花岗岩;岩石富集轻稀土元素,具铕负异常、铈轻微负异常;Rb、Th、La、Nd明显富集,Ba、Ta、Sr、Zr明显亏损。岩浆来源于地壳,是由地壳岩石部分熔融形成的。岩石具有同碰撞型花岗岩特征,推测岩体可能是可可西里-松潘前陆盆地闭合期间形成的碰撞型侵入岩。 相似文献
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四面山含榴混合花岗岩位于大别山北麓,主要为二长花岗质混合脉体。本文研究了该岩体的岩石学、地球化学特征并分析了岩石成因。结果表明,四面山含榴混合花岗岩具有高硅富碱的特征,整体属于准铝质到弱过铝质的高钾钙碱性花岗岩,但局部可能混合岩化不均匀;岩石富集Ba、Th、K而亏损Nb、Sr、P、Ti等元素;稀土总量(ΣREE)为115.05×10~(-6)~430.85×10~(-6),轻稀土元素相对富集,铕负异常整体不明显。初步研究表明,四面山含榴混合花岗岩是超高压地体折返到中下地壳,在拆沉、底侵等因素影响下经部分熔融形成的。 相似文献
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《矿物学报》2016,(2)
位于青海省东昆仑西部的野马泉地区三叠纪花岗岩分布广泛,本文通过花岗岩岩石学、地球化学、年代学研究,将晚古生代—早中生代造山旋回同碰撞阶段时限厘定为235~224 Ma,后碰撞时限厘定为224~204 Ma。研究表明,同碰撞阶段代表性侵入岩岩石组合为石英二长闪长岩-花岗闪长岩,具有钙碱性-高钾钙碱性系列准铝质-弱过铝质I型花岗岩的特征,岩石形成于下地壳或中下地壳,与幔源物质底侵作用和俯冲大洋物质"滞后"局部熔融有关,花岗闪长岩具有adakitic岩亲和性的特点。后碰撞阶段代表性侵入岩岩石组合为似斑状二长花岗岩-二长花岗岩-花岗斑岩,具有高钾钙碱性-钾玄岩系列准铝质-强过铝质S型花岗岩的特征,岩石形成于上地壳,含闪长质包体二长花岗岩源区具有EMⅡ富集地幔的印记,有别于不含包体的二长花岗岩。三叠纪花岗岩的形成可能经历了地幔底侵-洋壳"滞后"熔融和地壳熔融的深部过程。 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