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1.
骆驼山镁铁--超镁铁岩体主要岩石类型有单辉橄长岩、橄榄辉长苏长岩、橄长岩、辉长苏长岩、辉长岩。橄榄石Fo为76~83,为贵橄榄石。辉石化学特征以及主量元素特征表明其属拉斑玄武岩系列,稀土元素配分曲线总体表现为轻稀土稍富集、重稀土微分异的特征。微量元素具有大离子亲石元素(Rb、Ba、Sr)相对富集,高场强元素Ta、Hf、Th相对亏损的特征。岩浆演化过程中分离结晶作用主要受单斜辉石控制。Nb/U、Ce/Pb值更接近于地壳值以及敏感元素比值协变关系表明岩浆演化过程发生了同化混染作用。Th/Yb-Nb/Yb、La/Ba-La/Nb之间的关系指示岩浆源区可能为流体交代改造的富集型岩石圈地幔。 相似文献
2.
东天山黄山岩带因发育众多镁铁质-超镁铁质岩体和岩浆铜镍硫化物矿床而备受地质学者关注。四顶黑山岩体位于该岩带最东端,具有层状岩体特征;岩石类型有单辉橄榄岩、橄榄辉石岩、橄榄苏长辉长岩、橄榄辉长岩、辉石角闪岩、辉长岩、角闪辉长岩、闪长岩,主要造岩矿物为贵橄榄石、古铜辉石、透辉石、普通角闪石和斜长石,岩体分异较好,蚀变较发育。通过矿物显微结构特征观察以及计算得出:四顶黑山岩体中橄榄石最先结晶,其开始结晶温度大约在1419℃左右;古铜辉石和透辉石在橄榄石之后开始结晶,结晶温度分别在1100℃左右和900～1100℃之间,两矿物相在岩石中可以共存。岩体中橄榄岩相、苏长岩相发育,以及贵橄榄石+古铜辉石的矿物组合特征,表明岩体具有形成铜镍(铂)矿床的有利条件。 相似文献
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东天山黄山南镁铁-超镁铁质岩体锆石U-Pb年龄及岩浆演化过程探讨 总被引：1，自引：0，他引：1
黄山南镁铁-超镁铁质岩体位于东天山造山带觉罗塔格构造带内,与构造带内一系列镁铁-超镁铁质岩体构成了东天山镁铁-超镁铁质岩带。黄山南岩体锆石U-Pb同位素定年得到293.7±3.1Ma的加权平均年龄,显示其形成年龄为早二叠世。岩石样品镁铁比值m/f比值介于4.45~6.37之间,属于铁质超基性岩;利用橄榄石最高Fo值计算得到黄山南岩体母岩浆的Mg~#值为0.70,表明其母岩浆成分与原生岩浆较为接近,具有高镁拉斑玄武岩质岩浆的性质,且演化程度较低或母岩浆有过剩橄榄石堆晶的加入。Ba/La、Ba/Nb、Ba/Th、Rb/Nb、Th/Nb和Sm/Yb等微量元素比值表明黄山南岩体的岩浆源区可能为一被俯冲板片沉积物和流体改造过的较富集的岩石圈地幔。主量元素变化特征显示了岩浆结晶分异作用的一般特征;较高的Ba/Nb比值,相对高的La/Nb和低La/Ba值以及Ni-Ta-(Ti)元素的负异常表明岩浆上升过程中可能经历了地壳物质的混染作用。黄山南岩体年龄及岩石地球化学特征综合表明其能够代表东天山地区地幔岩浆演化早期阶段的产物,具有较好的成矿潜力。 相似文献
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云海铜镍矿位于觉罗塔格构造带西段,成矿岩体为多期次侵入的杂岩体,岩体分异演化充分,镁铁质和超镁铁质岩石均有发育,主要岩石类型为角闪辉石岩、橄榄苏长岩、辉长岩、闪长岩。主量元素化学组成表明,该杂岩体属拉斑玄武岩系列,岩石具同源演化特征,显示高铁、高镁、低钛、低铝特征,富集大离子亲石元素Rb,Ba,亏损Nb,Ta,轻稀土富集。岩浆源区有部分熔融而交代的岩石圈地幔,岩浆在上升过程中受到地壳物质混染,发生橄榄石、斜方辉石、斜长石的分离结晶。岩体形成于早二叠世,为构造活动和地幔柱双重作用下的产物。 相似文献
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新疆北山地区漩涡岭镁铁质—超镁铁质层状岩体岩石学与矿物学研究 总被引：2，自引：0，他引：2
位于新疆北山地区的漩涡岭岩体是一堆晶层理发育的镁铁质-超镁铁质层状岩体。岩石类型主要有纯橄岩、橄长岩、橄榄辉长岩和辉长岩等。主要的造岩矿物有橄榄石、辉石、斜长石、铬尖晶石,岩相学特征表明岩浆在演化过程中经历了橄榄石、尖晶石、斜长石、斜方辉石和单斜辉石的分离结晶,结晶次序依次为橄榄石+尖晶石→斜长石→辉石,表明结晶时压力较低。漩涡岭岩体的纯橄岩中橄榄石的Fo高达90.1,这不同于新疆北部黄山岩带、喀拉通克岩体群以及甘肃金川岩体的橄榄石Fo组成,利用橄榄石最高Fo值估算得到漩涡岭岩体的母岩浆的Mg#为0.73~0.75,岩浆的液相线温度高达1330~1350℃,其岩浆为高温高Mg的苦橄质岩浆,这为塔里木东北部二叠纪地幔柱活动提供了新的证据。 相似文献
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浪木日镁铁质-超镁铁质岩体位于东昆仑造山带东段,临近昆中断裂,主要由橄榄岩、橄榄辉石岩、辉石岩和辉长岩组成,且局部发育星点状和浸染状硫化物矿化。辉石岩和橄榄辉石岩获得的锆石U-Pb年龄分别为(421.2±1.2)Ma和(421.10±0.96)Ma,表明岩体侵位于晚志留世。岩石地球化学特征显,浪木日镁铁质-超镁铁质岩具有较高的Mg#(Mg#>80),富集LILE(Rb、Th、U等),亏损HFSE(Nb、Ta、Ti等),轻、重稀土元素分馏程度较强((La/Yb)N=6.28～50.91,(La/Sm)N=1.45～4.15,(Gd/Yb)N=1.43～9.71),具有弱的负Eu异常(δEu=0.226～0.824)。锆石Lu-Hf(εHf(t)=-2.9～-10)和全岩Sr-Nd(εNd(t)=-10.3～-8.9)同位素特征显示,其岩浆源区主要来自富集地幔,与俯冲洋壳脱水交代上覆地幔楔活动有关。综合研究表明,浪木日镁铁质-超镁铁... 相似文献
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哈拉乔拉镁铁质岩体位于新疆阿尔泰造山带东南缘, 主要岩石类型有辉长岩、辉长苏长岩、含长辉石岩、橄榄辉长岩和橄长岩.哈拉乔拉岩体具有低TiO2(0.09%~1.28%)、低碱(Na2O+K2O=0.37%~0.78%)的特点, 属于拉斑玄武岩系列; 富集大离子亲石元素和轻稀土元素, 亏损高场强元素(Nb、Ta等), εNd(t)为-2.62~-0.78, εSr(t)为37.49~45.28.元素地球化学和Nd-Sr同位素组成表明, 岩浆源区为被消减板片交代改造过的富集型岩石圈地幔.原生岩浆为高镁拉斑玄武岩浆, 岩浆演化过程中主要发生了橄榄石、单斜辉石以及斜长石的分离结晶/堆晶, 后期有钛铁矿的析出. 相似文献
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新疆黄山铜镍硫化物矿床成矿岩浆作用过程 总被引：10，自引：0，他引：10
黄山铜镍硫化物矿床镁铁．超镁铁质岩体岩相发育良好,主要包括橄榄岩、辉石岩、辉长岩和闪长岩,橄榄岩中部分橄榄石包含有硫化物珠滴。对该岩体不同岩相进行了主元素、微量元素、铂族元素和单矿物的分析,结果表明,不同类型岩石的化学组成受橄榄石、辉石和斜长石结晶分异作用的控制。微量元素和稀土元素具有相似的分布模式,（La／Yb）N介于1．14—3．65之间,明显亏损Nb和Ta,富集Sr。含矿岩石Cu／Pd和Ti／Pd比值大于原生地幔岩浆。上述结果揭示黄山镁铁-超镁铁质岩体不同岩性的岩石具有不同的主元素和微量元素特征,但母岩浆来自同一源区。根据橄榄石的F0值和全岩的主要氧化物组成估算出母岩浆为高镁（MgO约为15％）玄武岩岩浆,在岩浆作用过程中地壳富硅组分的混染是导致硫化物熔离的主要机制。 相似文献
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圪塔山口含铜镍镁铁-超镁铁质岩体位于东天山黄山–镜儿泉–图拉尔根铜镍矿带东段。岩体由I-1,I-2,I-3,I-4四个小岩体组成,主要岩石类型为辉石橄榄岩、橄榄辉石岩、辉长岩和闪长岩,主要赋矿岩相为辉石橄榄岩。I-2号含矿岩体锆石SHRIMP U-Pb年龄为275.0±3.6 Ma,与东天山地区含铜镍矿镁铁–超镁铁岩体形成时代相近,I-4号不含矿岩体锆石SHRIMP U-Pb年龄为364.2±3.9 Ma,明显早于含矿岩体。样品的主量元素组成显示岩浆演化过程主要发生了橄榄石和少量辉石的分离结晶/堆晶作用;稀土元素球粒陨石标准化配分曲线呈轻稀土略富集的右倾型,Eu异常不明显;微量元素特征显示相对富集大离子亲石元素(Cs、Sr、Ba),适度亏损高场强元素(Nb、Ta、Ti)。岩石地球化学特征表明岩浆演化过程中遭受了较弱的中–下地壳物质混染。U/Th-Th/Zr、Ba/Th-Th/Yb图解,La/Nb、La/Ba和Ba/Nb比值表明岩浆源区遭受了明显的俯冲流体交代作用。综合含矿岩体年代学、岩石地球化学特征及区域演化历史,认为圪塔山口含矿岩体形成于碰撞后伸展背景,可能同时叠加了塔里木地幔柱活动的影响。 相似文献
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青海省乌兰地区肯得隆富钛铁矿镁铁-超镁铁质岩体的岩石与矿石成因 总被引：3，自引：3，他引：0
肯得隆镁铁-超镁铁质岩体位于青海柴达木盆地北缘欧龙布鲁克微陆块中。岩体为半隐伏岩体,地表零星出露。岩体岩石类型丰富,有蛇纹岩、单辉橄榄岩、二辉橄榄岩、橄榄二辉岩、橄榄单辉岩、橄榄苏长辉长岩、橄榄角闪辉长岩、角闪辉长岩、蚀变辉长岩、斜长岩。辉长岩、辉石岩中见稀疏浸染状、星点浸染状钛铁矿。钛铁矿含量以5%~10%为主,个别含量可达10%~20%,具海绵陨铁结构,属岩浆晚期矿化作用产物。岩体中辉长岩锆石U-Pb年龄为491±3Ma(MSWD=0.7)。岩体岩石的化学组成属于拉斑玄武质系列,各岩性岩石的稀土元素配分形式基本一致,均呈轻稀土富集的右倾型。微量元素特征表现为富集大离子亲石元素(Cs、Rb、Ba、Th、U),亏损高场强元素(Nb、Ta、Ti、P)。岩体(87Sr/86Sr)i值为0.704731~0.710280,εNd(t)=-4.49~+0.83。岩浆在冷凝过程中发生了橄榄石-单斜辉石-斜方辉石-斜长石-普通角闪石的分离结晶作用。岩石地球化学特征表明岩体受到同化混染作用。肯得隆岩体的原生岩浆为普通的玄武质岩浆,源自被古生代俯冲熔/流体交代的富集岩石圈地幔。钛铁矿的富集机制是:岩浆在氧逸度低于NNO条件下经历了相对高度的分异演化而最终达到钛铁矿富集。 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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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
19.
《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
20.
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