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大陆碰撞造山带的流体成分与演化:东喜马拉雅构造结南迦巴瓦岩群高压麻粒岩的流体包裹体研究 总被引：2，自引：1，他引：1
位于喜马拉雅东构造结的南迦巴瓦岩群经历了高压麻粒岩相、中压麻粒岩相和角闪岩相三期变质作用.在高压麻粒岩中含有复杂的流体包裹体类型,按照捕获先后顺序有:H2O-CO2±CH4包裹体(Ⅰ型);CO2±CH4±N2包裹体(Ⅱ型);高盐度多相包裹体(Ш型);中.低盐度H2O包裹体(Ⅳ型)和极低密度气体包裹体或"空"包裹体(Ⅴ型).在基性麻粒岩中,被石榴石包裹石英中孤立分布的H2O-CO2 4-CH4包裹体,以及部分沿石榴石晶内裂隙分布的H2-CO2±CH4和H2O包裹体轨迹未穿过围绕石榴石的辉石 斜长石后成合晶冠状体,表明它们有可能是在麻粒岩相变质阶段捕获的.然而,所有流体包裹体的等容线均从麻粒岩相变质峰期P-T区间下方通过,说明麻粒岩相变质峰期捕获的包裹体均受到了不同程度的改造,包括部分爆裂、渗漏和流体-矿物相互作用等.现存的富CO2流体包裹体均具有较低密度,并且往往含有明显数量CH4和N2组分,不可能是麻粒岩相变质峰期捕获的包裹体.根据富CO2包裹体与具有不同相比的H2-CO2包裹体共存推测,大部分CO2包裹体是通过H2O-CO2包裹体中H2O的选择性泄漏而形成的.Ⅲ型高盐度盐水包裹体很可能是角闪岩相退变质过程中捕获的,因其等容线与退变质轨迹近于平行,这些包裹体很可能保存了其在角闪岩相阶段捕获时的原生物理化学特征.沿矿物颗粒裂隙分布的大量Ⅳ型和Ⅴ型包裹体,应该是角闪岩相或更晚期形成的次生包裹体,代表了浅成(近地表)环境的循环流体.与世界许多地区麻粒岩相岩石普遍舍高密度纯CO2流体包裹体不同,南迦巴瓦岩群高压麻粒岩以富含H2O-CO4±CH4和H2O包裹体为特征,这可能与高压麻粒岩与高温麻粒岩产出于不同的构造环境和经历的退变质轨迹有关. 相似文献
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对大别超高压变质带主要构造单元各类地质体岩石中的流体包裹体进行了岩相学和相变温度的观察与测定。流体包裹体类型和成分特征显示，与超高压变质、早期退变质有关的流体成分主要属于盐—H2O体系，减压熔融释放的流体成分主要属于NaCl—CO2—H2O体系，脆性变形期间涉及的成分流体主要属于NaCl—H2O体系。由于超高压变质岩系的快速折返抬升造成的压力迅速降低等影响，各个事件中形成的流体包裹体都发生了程度不同的颈缩及爆裂等捕获后变化，其密度大都已不能反映捕获时的状态。超高压变质和退变质岩石中常常叠加了与不同流体事件有关的流体包裹体组合，因此，对群体制样获得的各种化学成分和同位素成分等数据所做的各种地质解释风险较大。 相似文献
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本矿床大多数流体包裹体出现在晚期裂隙中，与含金裂隙有成因联系。包裹体主要有三类：（1）含少量CO2的高盐度水包裹体，（2）含少量水的富CO2包裹体，（3）低盐度的H2O－CO2包裹体。其中具恒定相比的H2O－CO2包裹体，其均一温度在285℃～390℃之间，而水包裹体的均一温度范围为60℃～295℃。前两类包裹体很可能是由含近于15－30mole%CO2的低盐度H2O－CO2流体离析而成，这两种晚期流体的不混溶性在金的成矿作用中起了重要作用。 相似文献
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本矿床大多数流体包裹体出现在晚期裂隙中，与含金裂隙有成因联系。包裹体主要有三类：（1）含少量CO2的高盐度水包裹体，（2）含少量水的富CO2包裹体，（3）低盐度的H2O－CO2包裹体。其中具恒定相比的H2O－CO2包裹体，其均一温度在285℃～390℃之间，而水包裹体的均一温度范围为60℃～295℃。前两类包裹体很可能是由含近于15－30mole%CO2的低盐度H2O－CO2流体离析而成，这两种晚期流体的不混溶性在金的成矿作用中起了重要作用。 相似文献
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中国大陆科学钻探（CCSD）主孔超高压变质岩副矿物锆石中的流体包裹体研究 总被引：2，自引：2，他引：2
中国大陆科学钻探工程主孔位于苏鲁超高压变质地体南部,钻孔穿过的超高压岩石主要有榴辉岩、正、副片麻岩、石榴橄榄岩、角闪岩,以及少量片岩和石英岩。锆石是超高压岩石中的常见副矿物,按成因可以分为原岩锆石、变质(增生)锆石和新生锆石。这三类锆石中普遍含有矿物包体和少量流体包裹体,它们记录了超高压岩石经历的进变质、超高压变质和退变质期间流体作用的信息。锆石中的流体包裹体具有以下特征:(1)原岩锆石核部常见原生H2O和H2O-CO2包裹体,H2O包裹体的组成和盐度变化较大;而沿原岩锆石裂隙有时还有次生H2O-CO2和(或)CO2包裹体;(2)在变质锆石或锆石的变质增生带(幔部或边部)仅偶尔发现与超高压矿物包体共生的H2O-CO2包裹体;(3)榴辉岩,特别是片麻岩可以含大量微粒新生锆石,其中偶尔可见低盐度的H2O±CO2包裹体;(4)锆石中流体包裹体的丰度与主岩氧同位素值存在一定相关性:即具有很低δ18O值的岩石所含锆石中流体包裹体特别丰富,而具有正常氧同位素组成的岩石中锆石很少或不合流体包裹体;结合原岩锆石、变质锆石和新生锆石中均有中低盐度的H2O和H2O-CO2包裹体存在,反映了在大陆深俯冲-折返过程中变质流体具有继承性。H2O和H2O-CO2包裹体的等容线全都从根据矿物温压计获得的变质峰期压力-温度区间下部通过,推测在进变质-超高压变质峰期捕获的流体包裹体随后受到了改造。在进变质-超高压变质和退变质期间变质流体的存在促进了原岩锆石不同程度地受到溶蚀、变质增生和变质锆石、新生锆石的形成。 相似文献
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湖南新宁县星子岩锑矿位于钦杭结合带中段湘中盆地内,脉状矿体受NE向硅化破碎带控制,直接容矿围岩为下寒武统香楠组碳质板岩和硅质板岩。文中对星子岩锑矿进行系统的矿物生成序列研究,将成矿过程分为两期3个阶段,即沉积期以碳质板岩内球状黄铁矿为代表,热液期早阶段脉状辉锑矿石英脉(局部夹围岩角砾)和晚阶段辉锑矿方解石脉。为进一步限定其成因,选取热液期与辉锑矿共生的早阶段石英和晚阶段的方解石进行流体包裹体研究。包裹体岩相学研究表明,热液期石英和方解石内广泛发育流体包裹体,主要类型为纯H2O型和CO2-H2O型流体包裹体。激光拉曼测试表明,CO2-H2O型包裹体气相主要成分为CO2,液相主要成分为H2O。显微测温过程中,当降温时可见CO2-H2O型包裹体由气液两相变为三相,其初熔温度为-60.0~-56.6 ℃,CO2部分均一温度为3.7~28.5 ℃,完全均一温度介于113~266 ℃,CO2笼合物熔化温度为3.0~9.6 ℃,对应的流体盐度w(NaCleqv.)为0.8%~12.0%。星子岩锑矿流体包裹体的中低温、低盐度和含CO2的特征与造山型金矿的变质流体成矿特征相吻合。综合星子岩锑矿的成矿大地构造背景、矿床地质和成矿流体特征,星子岩锑矿的精细成矿过程为：钦杭结合带在印支-燕山期发生强烈的陆壳叠置作用,富碳质含黄铁矿的寒武系地层发生变质变形脱挥发分作用,形成中低温、低盐度、富CO2和富集锑元素的变质热液;变质热液向上运移过程中,温度压力降低发生相分离,导致CO2逸失和流体沸腾作用,大量辉锑矿沉淀,最终形成有经济价值的矿体。湖南星子岩锑矿的矿床地质特征和成矿过程与造山型金矿一致,因此其成因类型为造山型锑矿。 相似文献
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四川丹巴燕子沟金矿床成矿流体不混溶的流体包裹体证据 总被引：2，自引：0，他引：2
四川丹巴燕子沟金矿床是产于泥盆系碳质板岩、千枚岩中的石英脉型金矿床,矿体形态呈脉状、似层状,明显受断裂构造和顺层韧性剪切带或层间破碎带控制。成矿过程可分为沉积期、热液期和表生期3个成矿期,其中热液成矿期为主要成矿期。该期石英脉中的流体包裹体分为H2O包裹体、CO2包裹体和CO2-H2O包裹体3大类,并以富含CO2-H2O包裹体为显著特征。加热时富H2O相CO2-H2O包裹体完全均一成H2O相,富CO2相CO2-H2O包裹体完全均一成CO2相,而且二者的完全均一温度和压力一致,说明它们是同期捕获的CO2-低盐水不混溶流体包裹体组合。当含CO2流体发生不混溶时,CO2的溶离使成矿流体中pH值升高、f(O2)降低,从而导致Au溶解度降低,这是形成本矿床的主要原因。成矿温度为393℃,成矿压力为148.5~179.0MPa,矿床属于高温高压的变质热液金矿床。 相似文献
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贵州丫他卡林型金矿床流体包裹体特征及其成矿意义 总被引：1，自引：0，他引：1
黔西南丫他金矿床是典型的沉积岩容矿的微细浸染型金矿床。从流体包裹体的角度,探讨了丫他金矿床成矿的温度压力条件和流体演化。各阶段石英、雄黄的流体包裹体岩相学和显微测温研究结果表明:主成矿阶段包裹体主要类型有H2O、CO2和CO2-H2O包裹体,流体包裹体组合呈现CO2-H2O不混溶的特征,晚成矿阶段包裹体类型主要为H2O包裹体;从主成矿阶段到晚成矿阶段,流体包裹体均一温度由139～268℃变化至121～194℃,盐度由2.9%～7.4%变化至2.7%～6.6%。根据共存CO2包裹体和H2O包裹体的等容线计算法,还原主成矿期包裹体捕获温度为260～294℃,捕获压力为59～98 MPa。对比不同类型金矿床中的富CO2流体特征,指出黔西南卡林型金矿床中存在的富CO2流体可能在金的搬运过程中起到一定的作用,CO2-H2O相分离可能是导致矿质沉淀的主要原因。 相似文献
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五台山区太古宙铁建造型金矿成矿流体性质和成因 总被引：1，自引：0，他引：1
五台山区铁建造金矿经历初生成矿作用和叠加成矿作用。初生成矿作用形成于变质峰期之后 ,与区域变质作用有关。矿石富含水溶液包裹体。包裹体均一温度 171～ 2 55℃ ,压力 0 .12～ 0 .31GPa。流体成分模式Au -H2 S NaCl-CO2 -H2 O。氢氧同位素具变质水和雨水双重性 ,流体主要来源于变质热液 ,受雨水混合。叠加成矿作用可能受岩浆活动影响 ,矿石富含CO2 包裹体 ,均一温度 30 6～ 385℃ ,压力 0 .6～ 1.0 5GPa ,流体盐度较高 ,成矿流体可能与岩浆热液有关。 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
19.
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
20.
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