共查询到20条相似文献，搜索用时 93 毫秒
1.
达拉库岸镁铁-超镁铁质岩体位于东昆仑造山带南带之喀拉米兰晚古生代沟弧系,主要由二辉橄榄岩、单辉橄榄岩、橄榄二辉岩、单辉辉石岩和辉长岩组成。辉长岩的锆石U-Pb谐和年龄为244.4±1.5Ma,属于中三叠世。岩石普遍弱富集稀土元素和大离子亲石元素(Rb、Ba、Sr),亏损不相容元素(Nb、Ta)。岩体原生岩浆为高镁拉斑玄武质岩浆(Mg O 11.4%,Fe O10.8%)。元素地球化学和Nd、Sr同位素组成特征表明岩浆源区为富集岩石圈地幔,岩浆运移和侵位过程中遭受不同程度地壳物质的同化混染作用。依据橄榄石组分模拟获得橄榄石结晶过程中母岩浆达到硫饱和,并发生硫化物的熔离作用。从岩体特征、矿石结构、原生岩浆性质、深部硫化物熔离和物探信息等方面综合分析,岩体具有形成岩浆型铜镍硫化物矿床的良好条件。 相似文献
2.
阿拉善地块南缘北大山地区野芨里镁铁-超镁铁质岩体主要由单辉橄榄岩、二辉橄榄岩、橄榄辉长岩组成。岩体局部发现了硫化物,主要由磁黄铁矿、镍黄铁矿与黄铜矿组成,指示岩浆结晶过程中发生了硫化物不混溶作用。岩石地球化学分析显示野芨里岩体属于铁质超基性岩,富集大离子亲石元素,相对亏损高场强元素,具有明显的Nb,Ta负异常,微量元素比值指示岩浆在上升过程中受到了中上地壳物质混染。橄榄辉长岩中锆石SHRIMP U-Pb年龄为286.6±2.5 Ma,属于早二叠世。结合区域构造演化,认为野芨里岩体形成背景可能与古亚洲洋的闭合或俯冲之后的伸展作用相关。 相似文献
3.
新疆中天山白石泉含铜镍矿镁铁-超镁铁岩体地球化学特征与岩石成因 总被引：3，自引：4，他引：3
白石泉含Cu-Ni硫化物镁铁-超镁铁侵入体位于中天山地块,其主要岩石类型有辉石橄榄岩、橄榄辉石岩、橄长岩、辉长岩及角闪辉长岩等,具有明显的堆晶结构.对岩体的主要、微量及稀土元素地球化学特征研究表明,岩体属铁质镁铁-超镁铁岩,具有拉斑玄武质岩浆的分异趋势;并相对富集大离子亲石元素(Rb、Ba、Sr等)、亏损高场强元素(Nb、Ta、Zr、Hf),以及具有LREE富集((La/Yb)n=1.27～9.95)的右倾型稀土元素分布模式.Pb同位特征表明母岩浆与软流圈地幔和EM Ⅱ地幔物质有关.综合地球化学特征表明,母岩浆为来源于受早期俯冲物质混染的软流圈地幔的高镟拉斑玄武岩浆.岩浆在上升过程中,没有受到上地壳及围岩的混染.原生岩浆形成后,经过了橄榄石、辉石、斜长石及铬铁矿的分离结晶作用和硫化物的熔离作用.目前出露的岩体为富含橄榄石及硫化物的“晶粥“在高位岩浆房中演化的产物. 相似文献
4.
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
5.
东天山白鑫滩含铜镍矿镁铁-超镁铁岩体的岩石成因:年代学、岩石地球化学和Sr-Nd同位素证据 总被引：3，自引：2，他引：1
自20世纪70年代以来,新疆东天山觉罗塔格构造带库姆塔格沙垅以东地区发现了大量的镁铁-超镁铁岩体和岩浆铜镍硫化物矿床,但是在沙垅以西地区没有大的找矿突破。白鑫滩含铜镍矿镁铁-超镁铁岩体为近几年在库姆塔格沙垅以西地区发现的岩浆铜镍硫化物矿床,研究工作薄弱,本文通过对白鑫滩岩体的岩石学、年代学、岩石地球化学和Sr-Nd同位素分析来解释其岩石成因。白鑫滩岩体不同岩相中矿物的粒径和含量的变化规律说明岩体为三期岩浆侵入作用形成,第一期为顶部的角闪辉长岩;第二期的橄榄辉长岩、斜长二辉橄榄岩和含长橄榄二辉岩,矿物种类相同,含量呈渐变关系;第三期为底部为的辉长岩,矿物粒径相对顶部的角闪辉长岩较小。白鑫滩岩体与黄山东、黄山西岩体具有相似的稀土元素和微量元素配分型式,大离子亲石元素(Rb、Ba、U、K)相对富集,而部分高场强元素(Nb、Ta、Ti)相对亏损,稀土元素呈轻稀土略微富集的右倾样式,均表现出岛弧火山岩的地球化学性质,εNd(t)值(2. 84～5. 05)和(~(87)Sr/~(86)Sr)(t)值(0. 704113～0. 705682)介于软流圈地幔与岩石圈地幔之间。但是与黄山东、黄山西岩体相比,白鑫滩岩体不相容元素含量更高,且εNd(t)值更低,(87Sr/86Sr)(t)值更高,还具有较高的La/Nb(2. 00～3. 33),较低的La/Ba(0. 02～0. 15),这些特征说明白鑫滩岩体的原始岩浆为岩石圈与软流圈物质相互作用的产物,且白鑫滩岩体的原始岩浆中软流圈物质相对于黄山东和黄山西岩体加入的比例更小。白鑫滩橄榄辉长岩年龄为287±3Ma,晚于该地区蛇绿岩(336～503Ma)、岛弧火山岩(320～322Ma)、岛弧花岗岩(316～328Ma)和含矿斑岩侵入体(326～334Ma)的年龄,与A型花岗岩和双峰式火山岩(284～294Ma)的年龄基本一致,而且白鑫滩岩体单斜辉石的化学成分与拉张裂谷环境的堆晶岩相似,因此推断白鑫滩岩体形成于后碰撞拉张环境。 相似文献
6.
7.
新疆东天山黄山东岩体岩石地球化学特征与岩石成因 总被引：12，自引：7，他引：5
黄山东岩体位于东天山北部的土墩-黄山-图拉尔根镁铁-超镁铁质岩带中段,受康古尔塔格-黄山深大断裂控制,是由辉长闪长岩、角闪辉长岩、橄榄辉长岩、辉长苏长岩及二辉橄榄岩组成的复式岩体。主量元素化学组成部分属拉斑玄武岩系列,也有部分属钙碱性系列。大部分岩石相对富集LREE、适度亏损高场强元素(Nb、Ta、Ti)。元素地球化学和Nd、Sr、Pb同位素体系证明,岩浆遭受了5%～8%的中-上地壳物质的同化混染作用。岩浆源区由被消减板片交代的地幔楔物质和软流圈地幔物质组成。岩石圈根部拆沉和软流圈地幔上涌过程中生成了黄山东岩体。富铁硅酸盐的分离结晶作用对硫化物富集并分凝起到了关键性作用,成矿过程应该是岩浆自身演化过程的有机组成部分。 相似文献
8.
牛毛泉基性杂岩体位于准噶尔古板块博格达-哈尔里克晚古生代岛弧东段,赋存磁铁矿。研究表明,该岩体具有明显成层性和韵律构造特征,主要岩石类型有橄榄辉长岩、含橄榄辉长岩、辉长岩和角闪辉长岩。岩石地球化学特征表明,该套岩石属拉斑玄武岩系列,m/f值介于0.65~1.44之间,属铁质基性-超基性岩。岩石稀土元素总量相对较低,稀土元素配分曲线为轻稀土元素略富集的右倾型;岩石富集大离子亲石元素(Rb、Ba、Sr、U),相对亏损高场强元素(Zr、Hf),具有明显的Nb、Ta负异常和弱的Ti正异常。岩石εNd(t)=-3.4~-0.50,εSr(t)=-3.4~8.5,具有向EMⅠ方向演化的趋势,表明岩浆源区可能为受俯冲流体交代改造的富集岩石圈地幔,是新疆北部早二叠世时期后碰撞伸展阶段的产物,由拆沉的富集岩石圈地幔被软流圈加热后发生部分熔融并上侵形成。 相似文献
9.
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
10.
江苏省宁镇地区位于长江中下游沿江成矿带的最东端,是长江中下游成矿带的重要组成部分,蒋庙岩体是宁镇地区唯一的基性岩体.对此岩体进行了锆石U-Pb年代学、矿物化学、岩石地球化学和Sr-Nd-Hf同位素研究,讨论了其成因及地幔源区性质.岩体主要由橄榄辉长岩、角闪辉长岩和辉石闪长岩组成,其中辉石闪长岩的锆石LA-ICP-MS(laser ablation inductively coupled plasma mass spectrometry) U-Pb年龄为121±1 Ma.锆石εHf(t)值介于-2.9~-6.4.全岩地球化学研究显示岩石样品富钠低钾,富集轻稀土元素,重稀土元素亏损不明显,富集大离子亲石元素(如K、Ba、Sr等),亏损高场强元素(如Nb、Ta、Ti、Zr、Hf等).蒋庙基性侵入岩在长江中下游地区中生代岩浆岩中具有最高的εNd(t)值以及最低的(87Sr/86Sr)i值,其Sr-Nd同位素组成介于软流圈地幔(depleted MORB mantle,DMM)-富集岩石圈地幔(enriched mantle Ⅱ,EMⅡ)之间.研究认为,蒋庙岩体应来源于软流圈地幔和富集岩石圈地幔的混合组分,可能有少量的俯冲板片物质加入源区,并在成岩过程中经历了一定程度的结晶分异.结合区域地质、年代学、矿物学和地球化学资料,表明蒋庙岩体的形成可能与古太平洋板块俯冲事件密切相关. 相似文献
11.
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
12.
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
13.
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
14.
15.
16.
17.
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
18.
《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
19.
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
20.
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