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101.
Takenori Kato 《Geostandards and Geoanalytical Research》2005,29(1):83-94
A new α-factor table for the Bence-Albee correction method of quantitative electron microprobe analysi is presented for an accelerating voltage of 15 kV and a take-off angle of 40 degrees. The α-factors were calculated from the full PAP correction with least squares fitting in the range 0.1–50% m/m in C/K-C space, with the assumption that C/K = 1 for C = 1, where C is the weight fraction of the emitting element as oxide or anion in binary oxide-oxide, oxide-anion or anion-anion systems, and K is the relative X-ray intensity ratio between compound and pure oxide or anion. Recently determined mass attenuation coefficients were chosen. X-ray intensities were calculated for binary oxide-oxide, oxide-anion and anion-anion systems. For the twelve major elements that characterise most geological samples, maximum deviations of α-factors in this study were smaller than 10 % and most deviations were less than 1%. The new α-factor table improves the accuracy of the Bence-Albee method compared with previous studies, and provides results as accurate as the full PAP correction when absorption is not large. 相似文献
102.
Nobutaka Shimada Tomoki Nakamura Yasuo Morinaga Yoshihito Shikama 《Resource Geology》2005,55(2):91-100
Abstract. The presence of invisible gold was confirmed in arsenian pyrite from the Hishikari epithermal gold deposit, Kagoshima, Japan, by means of EPMA and SIMS analyses. The relative concentration of invisible gold may be positively correlated with As contents (0.01 to 10.37 wt%) of fine-grained arsenian pyrite which commonly occurs in the auriferous quartz veins. Although arsenian pyrite occurs widely in any mineralization stage with electrum and other sulfide, sulfosalts, selenide or telluride minerals, arsenian pyrites having higher As contents accompanied by invisible gold occur dominantly in the middle stage of fine-adularia-quartz and in the late stage of coarse-quartz rather than in the early stage of columnar-adularia. 相似文献
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104.
广东莲花山断裂带西南段分布有棉洋-双华(Ⅰ)、北山嶂-九龙嶂(Ⅱ)、五指嶂-锅子嶂(Ⅲ)、梅陇-鲘门-观音山(Ⅳ)4条韧性剪切带,呈巨型构造透镜体沿北东向展布。已有研究表明韧性剪切带与本区钨、锡、铜多金属成矿作用关系密切,控制着矿床的空间分布,是重要含矿、控矿构造。按照变质程度和矿物组成,区内韧性剪切带由核部至边部可以划分为石英透镜体→石榴子石(堇青石)糜棱岩→糜棱片岩→片岩→原岩等;通过对其中的石榴子石、黑云母等典型矿物进行电子探针分析(EPMA),并利用石榴石-黑云母地质温压计估算了 4条韧性剪切带形成的温压条件,它们分别为484~526℃/4.92~7.72kbar、458~469℃/2.17 ~2.67kbar、536~551 ℃/1.28~1.67kbar、512~516℃/4.38 ~4.87kbar,与区内变质岩野外地质变形、变质特征相吻合,且火山岩为主的地区变质压力明显高于花岗岩为主的地区。研究显示,变质条件对区内变质分带和多金属成矿作用有明显的控制,棉洋-双华和梅陇-鲘门-观音山韧性剪切带的压力条件相对较高,金属成矿以钨、锡多金属成矿为主;而北山嶂-九龙嶂和五指嶂-锅子嶂韧性剪切带的压力相对较低,金属成矿则以铜、铅、锌成矿为主。 相似文献
105.
The Mirge-Naqshineh gold district is situated at northwest of Iran with a NW-trending brittleductile shear zone. It is hosted by Precambrian meta-sedimentary and meta-volcanic units traversed by mineralized quartz veins. In terms of cross-cutting relationships and sulfide content three types of quartz veins are identified in the region. Among those, parallel to bedding quartz vein(type Ⅰ) is the main host for gold mineralization. Gold is found in three different forms: 1) submicrometer-size inclusions of gold in arsenian pyrite, 2) as electrum and 3) in the crystal lattice of sulfides(pyrite, galena and chalcopyrite). Six types of pyrite(Py1-Py6) were identified in this ore reserve. Py3 coexists with arsenopyrite and contains the greatest As-Au concentrations. There is a negative correlation between the As and S contents in Py2 and Py3, implying the substitution of sulfur by arsenic. Pyrites and mineralized quartz veins were formed via metamorphic-hydrothermal fluid and reflect the gold-transportation as Au(HS)_2~- under reducing and acidic conditions. The gold precipitation mainly controlled by crystallization of arsenian pyrite during fluid/rock interactions and variation of fO_2. The volcanic host rock has played an important role in gold concentration, as Py3 in this rock contains inclusion of gold particles, but gold is within the lattice of pyrite in phyllite or other units. 相似文献
106.
对单颗粒电子探针能谱定量分析涉及的样品制备方法、定量分析校正方法、测试条件以及数据处理方法等进行了简要介绍,并对该技术的最新研究成果、发展趋势及其应用前景进行了评述,最后指出了国内在该研究领域存在的问题并提出了相应的解决方案。 相似文献
107.
GZAF电子探针分析和控制系统软件Windows版采用VB和VC自主开发, 可运行于Win98等操作系统下.具有较全面的电子探针分析和控制功能, 主要有: 硬件系统设置、校正和驱动、定量分析及数据处理、多种定性分析模式、大样品线扫描分析、大样品面/线自动/手动布点定量分析及相应的图像生成和显示、X射线特征谱分析、薄膜厚度分析等.分析报告方式有电子表格、数据库、文本文件、平面或立体图形和图像文件.所有报告都可以直接在Of fice、WPS、Access、Photoshop等通用软件中引用和加工.该软件移植性强, 只要提供32位标准的电子探针硬件接口, GZAF即可应用于任何厂家的电子探针上.GZAF可以半脱机或完全脱机使用, 灵活方便地为所有探针用户服务. 相似文献
108.
109.
向阳坪铀矿床是近年在苗儿山地区发现的重要矿床,绿泥石化是向阳坪铀矿床重要的蚀变类型和找矿标志。本文对向阳坪矿床发现的铀-绿泥石型矿石的蚀变矿物学特征进行了系统地观察,结合电子探针原位微区分析,查明了绿泥石相关矿物的共生组合关系,获得了其化学定量分析结果,划分了绿泥石的种类及其形成条件,在此基础上探讨了绿泥石性质及其对铀成矿的启示。结果显示,向阳坪铀矿床绿泥石可分为黑云母蚀变型、裂隙充填型、铀矿物相关型和黏土矿物吸附铁镁质转变型4种。铁硅协变图解表明向阳坪矿床主体为铁镁绿泥石,部分为蠕绿泥石,含少量的密绿泥石。据经验公式计算所得绿泥石形成温度变化范围为190~265℃,平均239℃,属中低温热液蚀变,其形成机制包括溶蚀-结晶和溶蚀-迁移-结晶2种。绿泥石化为铀成矿过程提供了所需的环境,促进了铀的活化、迁移并最终沉淀成矿。 相似文献