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1.
丁家山铅锌矿床位于梅仙矿田东南部,矿区内普遍发育石榴子石、辉石、绿帘石等脉石矿物,为探讨该矿床成因,对该矿床脉石矿物进行了电子探针、激光剥蚀电感耦合等离子质谱仪(LA-ICP-MS)原位U-Pb定年和微量元素分析。结果表明,石榴子石主要为钙铁-钙铝榴石固溶体系列,含有少量的锰铝榴石和铁铝榴石;辉石为透辉石-钙铁辉石-钙锰辉石固溶体系列;绿帘石族矿物属于绿帘石范畴。石榴子石的206Pb/238U下交点年龄为143.7 Ma,与成矿花岗岩年龄接近。依据石榴子石原位微量元素特征差异及Eu异常将石榴子石分为钙铁榴石(I型)和钙铁-钙铝榴石(II型)两类。钙铁榴石整体呈现轻稀土富集,重稀土亏损的稀土配分模式,I-1型钙铁榴石Eu具有明显的负异常,I-2型钙铁榴石Eu具有明显的正异常;钙铁-钙铝榴石整体呈现重稀土富集,轻稀土亏损的稀土配分模式,II-1型钙铁-钙铝榴石Eu具有明显的负异常,II-2型钙铁-钙铝榴石Eu具有明显的正异常。上述特征表明,石榴子石核部环境为弱氧化-弱还原,边部为氧化环境。综合地质学、矿物学、地质年代学数据以及地球化学特征,本文认...  相似文献   

2.
本文对荷花坪锡多金属矿,锡田锡钨多金属矿以及新田岭钨矿矽卡岩中的石榴子石样品分别进行了主量元素、微量元素及红外光谱测定。结果表明,3种矽卡岩中的石榴子石多数属于(铁铝榴石+镁铝榴石+锰铝榴石)<15%的钙铁-钙铝榴石系列。新田岭钨矿的石榴子石中钙铁榴石端员含量明显高于其他两个锡矿。此外,在荷花坪、新田岭矿区发现了与后期铅锌矿化有关的锰质石榴子石。在单矿物尺度上,荷花坪矿区石榴子石核部富集钙铝榴石,边部富集钙铁榴石,而锡田矿区石榴子石与之相反;新田岭矿区石榴子石具有相对均匀的核部而边部发育细密的振荡环带。在稀土配分模式上,荷花坪矿区石榴子石重稀土富集,轻稀土亏损,δEu负异常较弱;锡田矿区石榴子石稀土总量最高,轻重稀土无明显分异,δEu负异常较弱;新田岭矿区石榴子石轻重稀土分异极强,重稀土富集,轻稀土严重亏损,δEu具显著的正异常。3种石榴子石的红外漫反射光谱均显示有10种吸收峰,其中低频区的5种与石榴子石成分中的钙铁榴石含量直接相关,因而造成新田岭矿区石榴子石的吸收峰与另两矿区石榴子石相比显著向低频波段移动。通过对华南3类含钨锡矽卡岩中的石榴子石的研究,确认了石榴子石的形成与矽卡岩形成中热液体系的环境变化密切相关。微量元素分析与红外光谱技术作为近年来矽卡岩型石榴子石研究的热点,能够提供传统研究中所不能涉及的微观信息。  相似文献   

3.
单连芳 《矿物学报》1990,10(3):255-258
在河北省沙河县坡山铁矿区见到一种白色钙铝榴石。呈致密块状产在黑云母闪长岩中钙夕卡岩团块中。与黑榴石、钙铁榴石、硅灰石、符山石、透辉石以及其它钙铝榴石共生。此矿物呈半自形粒状,粒径为5—40mm。本文介绍了它的物理性质,化学成分,X射线衍射和红外吸收光谱等一系列分析资料。  相似文献   

4.
本文利用电子探针(EMPA)和激光剥蚀电感耦合等离子体质谱(LA-ICPMS)对湖北金山店大型矽卡岩型铁矿中的石榴子石开展了原位微区分析研究,并探讨其成分变化所蕴含的地质意义。金山店铁矿中的石榴子石可以分为早晚两期:早期石榴子石为钙铝榴石和钙铝榴石-钙铁榴石系列,而晚期石榴子石则主要为钙铁榴石,不同阶段石榴子石成分的变化暗示从早到晚流体氧化性增强。晚期石榴子石相比早期石榴子石富含大离子亲石元素、高场强元素和稀土元素。早期石榴子石中钙铝榴石强烈富集HREE,稀土配分模式为左倾型;而钙铝榴石-钙铁榴石系列则轻重稀土元素分异相对较小。不同的晚期石榴子石样品之间REE含量、δEu和轻重稀土分异程度差异较大,甚至个别石榴子石颗粒不同部位的差异也较大,暗示其形成过程中流体性质发生了剧烈的变化,可能与含膏盐地层的加入有关。石榴子石原位微区分析研究暗示含膏盐地层加入金山店铁矿成矿体系可能具有不均一性和阶段性。  相似文献   

5.
老硐沟金矿是北山成矿带东段发现的中型金矿床,是多期次多阶段成矿作用叠加的产物,矿床成因类型复杂。矿床共分为5个矿段,其中Ⅲ矿段以矽卡岩矿体为主。矽卡岩矿物以石榴子石为主,可分为早、晚两期,早期石榴子石更具震荡环带。通过详细的镜下观察和电子探针对两期石榴子石进行了系统研究,早期石榴子石核部以钙铝榴石组分为主,向边部为钙铁-钙铝过渡组分;晚期石榴子石以钙铁榴石为主。石榴子石化学成分特征表明,早期矽卡岩化阶段,热液环境为中酸性、弱氧化—弱还原环境;后期铁质含量增多,氧逸度增加,热液环境碱性、氧化性增强。老硐沟金矿Ⅲ矿段石榴子石为钙铁-钙铝榴石系列,属热液交代成因,早期多形成钙铝-钙铁榴石,伴随铜矿化,晚期热液环境变化,钙铁榴石增多,黄铁矿化、毒砂矿化增多,造成金富集成矿。  相似文献   

6.
山西刁泉银铜矿为矽卡岩型矿床,矿区内存在石榴子石矽卡岩和辉石石榴子石矽卡岩。多数情况下,这两类矽卡岩不共存,只在辉石石榴子石矽卡岩中见石榴子石矽卡岩角砾。X-射线衍射分析显示石榴子石矽卡岩由98.5%的石榴子石(包括钙铁榴石、钙铬榴石、钙钒榴石)和1.4%的石英组成;辉石石榴子石矽卡岩由71.4%的石榴子石(包括钙铁榴石、钙铬榴石、钙钒榴石)和28.5%的透辉石组成。这两类矽卡岩的微量元素、稀土元素特征基本相同,其矿化均与石英有密切关系,由于辉石石榴子石矽卡岩叠加了较多石英脉,其含矿性明显优于石榴子石矽卡岩。作者根据矿区地质背景和两类矽卡岩的特征分析,认为这两类矽卡岩的形成与燕山晚期不同期次的岩浆活动有关,石榴子石矽卡岩的形成时间早于辉石石榴予石矽卡岩;矿区燕山晚期与成矿有关的岩浆热液存在脉动现象,这种多期次岩浆热液活动的叠加有利于成矿;叠加了石英脉的辉石石榴子石矽卡岩可以作为该矿区找矿标志之一。  相似文献   

7.
本文对中国十四个接触交代钙夕卡岩矿床和钙-镁夕卡岩矿床中的三百多个样品的石榴子石和辉石成分进行了电子探针分析。不同矿床类型的石榴子石和辉石成分代表着钙夕卡岩矿床的十个矿种(Fe、Fe-Cu、Pb-Zn、W、Sn、Sn-Mo-Bi-W、、W-Bi-Cu-Mo、Cu-Zn、Cu-Sn、W-Zn-Cu)和钙-镁夕卡岩矿床的三个矿种(Fe-Cu、Mo、Pb-Zn)。石榴子石和辉石成分变化范围大,大多数石榴子石是含锰铝榴石+铁铝榴石+镁铝榴石小于15%(摩尔百分数)的钙铝榴石-钙铁榴石固溶体;大多数辉石是含小于5%的锰钙辉石的透辉石-钙铁辉石固溶体。有些Pb-Zn钙-镁夕卡岩矿床中的辉石显示出Mn含量有所增加。只有Sn和W钙夕卡岩矿床及Pb-Zn钙-镁夕卡岩矿床含(Sps+Alm+Pyr)总量大于15%的石榴子石。石榴子石和辉石成分与夕卡岩矿床金属矿化类型之间有某些联系。  相似文献   

8.
西藏知不拉铜多金属床是冈底斯成矿带东段典型的矽卡岩矿床,石榴子石是矿区最主要的矽卡岩矿物,其颗粒间的空隙是金属矿物的主要赋存部位。本文通过详细的钻孔编录,结合岩矿鉴定及电子探针分析,划分出两种不同类型的石榴子环带,并在垂向上具有明显的分带:产于顶板凝灰岩中的石榴子石以钙铁榴石为主,环带中心颜色深,向外逐渐变浅,由纯钙铁榴石过渡到钙铝榴石;而位于底板大理岩附近石榴子石多以钙铝榴石为主,从环带核部向外颜色变深,化学组成由钙铝榴石向钙铁榴石变化,其它化学成分变化不大。反映该区上下两套不同性质围岩在石榴子石形成过程中所起的作用不同,其中上部凝灰岩主要提供了Fe,底部大理岩则是Ca的来源,热液流体贡献Si、Al及部分Fe,并随着环境和物质成分改变导致环带外侧具有不同于核部的变化趋势。这很好地解释了石榴子石矽卡岩在空间上具有上部为钙铁榴石、向下逐渐过渡到钙铝榴石的空间分带。石榴子石特征及分带显示了其属热液接触交代成因,这为矿床类型的确定提供了依据,也为在该区域内寻找类似矿床指明了方向。  相似文献   

9.
太行山北段浮图峪矿田石榴子石环带特征研究   总被引:1,自引:1,他引:0  
聂飞  董国臣  王霞  朱华平 《岩矿测试》2014,33(3):439-449
位于华北克拉通中部太行山北段的浮图峪矿田由七个中小型矽卡岩型铜铁矿床和木吉村大型斑岩铜(钼)矿组成。石榴子石是浮图峪矿田矽卡岩型矿床的主要矿物,与矿化关系密切,是展开浮图峪矿田成因研究的一个重要切入点。本文对其中四个典型矽卡岩型矿床中与矿化密切相关的石榴子石进行野外地质调研、岩相学特征研究,运用电子探针分析石榴子石环带的化学成分。研究结果表明,石榴子石成分属钙铁-钙铝榴石系列;从晶体核部到边缘,钙铁榴石与钙铝榴石呈韵律式变化,总体上钙铁榴石组分的质量分数(78.1%~86.2%)大于钙铝榴石(12.91%~16.61%)。根据石榴子石的环带结构及其成分特征,认为石榴子石是在弱酸、较低温度和相对氧化的环境中生成的,指示成岩成矿流体温度、pH、氧逸度和盐度均在不断地发生变化,说明石榴子石不是在一个完全封闭的平衡条件形成的,暗示流体的多期多阶段性,这是矽卡岩型矿床富集金属的前提条件和重要因素。  相似文献   

10.
金船塘锡铋矿床是东坡矿田内一以锡铋为主的大型矽卡岩型多金属矿床。本文在详细野外地质考察、镜下观察以及电子探针分析的基础上,利用高精度LA-ICP-MS对该矿床的矽卡岩内石榴子石原位的微量元素进行了系统的分析。结果表明,金船塘锡铋矿床的钙铝榴石(Gro)大体上具重稀土(HREE)富集、轻稀土(LREE)亏损,负Eu异常的特征;而钙铁榴石(And)不同样品之间存在一定差异性,有的样品显示HREE富集、LREE亏损的特征,有的则轻重稀土分异不明显,除了多数呈Eu负异常外,还有部分表现为弱的正Eu异常,这可能是受钙铝-钙铁榴石混合物中的静电作用所导致。并且,上述不同石榴子石REE分配的差异还进一步指示,钙铝榴石(Gro)矿物生长速率较低,与孔隙流体之间基本保持动态平衡,水/岩(W/R)比值较低,其REE的化学行为主要受到晶体化学等机制的影响;钙铁榴石(And)矿物生长速率较高,具有较高的水/岩(W/R)比值,吸附作用在REE配分模式中起到重要作用。总体上,矽卡岩内的石榴子石的REE的分配呈HREE富集、LREE亏损,负Eu异常的特征,与千里山花岗岩REE分配模式一致,指示了金船塘锡铋矿床的成矿作用可能与千里山花岗岩体具有密切的成因联系。  相似文献   

11.
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.
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   

13.
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   

14.
本文介绍样品经四硼酸锂熔融制成玻璃小饼。采用Lachance模式和理论a系数来校正元素间的效应,由3080E型X-射线荧光谱仪和DF-350B数据处理系统完成硅酸盐中十三个项目的测定。  相似文献   

15.
本文拟定了一种以熔融法制备样片,用X射线荧光光谱测定硅酸盐类样品中Si、Fe、Al、Tj、Mn、Ca、Mg、K、Na、P等元素的分析方法。在对不同靶材X光管和分光晶体实验对比的基础上,选择了最佳的测量条件。该法具有快速、准确,测量范围广,检测限低,价格便宜等优点。经过近百个各种类型标样或管理样品的分析对比表明,本法不仅适用于硅酸盐类岩石样品的分析,还适用于铁矿、铝土矿、碳酸盐类岩矿样品以及水泥、耐火材料等样品的分析。  相似文献   

16.
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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18.
Between 1985 and 1991, two new mountain protected areas (MTNPA) covering more than 35,000 km2 and based on participatory management models — the Makalu-Barun National Park and Conservation Area, Nepal, and Qomolangma Nature Preserve, Tibet Autonomous Region — were successfully established through the collaborative efforts of Woodlands Mountain Institute and conservationists in China and Nepal. Characteristics common to both projects include the importance of establishing (1) effective rationales, (2) local support constituencies, (3) a senior advisory group, (4) a task force, (5) linkages between conservation and development, and (6) fund raising mechanisms. The lessons derived from the experiences of Woodlands Mountain Institute are of significant value to others in preserving MTNPA. Increased collaboration and communication between all interested in conservation, however, will remain a critical component for expanding mountain protected area coverage to throughout the world.  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.
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-Al2O3-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   

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