...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Contributions to Mineralogy and Petrology >Primary cumulus platinum minerals in the Monts de Cristal Complex, Gabon: magmatic microenvironments inferred from high-definition X-ray fluorescence microscopy
【24h】

Primary cumulus platinum minerals in the Monts de Cristal Complex, Gabon: magmatic microenvironments inferred from high-definition X-ray fluorescence microscopy

机译：加蓬Monts de Cristal矿场中的主要积云铂矿物质：从高清晰度X射线荧光显微镜观察得出的岩浆微环境

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

An unusual occurrence of Pt-enriched pyroxenites in the Monts de Cristal igneous complex is characterized by unusually high ratios of Pt to other platinum-group elements (PGEs) and very low Cu and sulfide contents. Synchrotron X-ray fluorescence microscopy was used to identify over a hundred discrete grains of platinum minerals and relate their occurrence to textural associations in the host heteradcumulate orthopyroxenites. Element associations, backed up by FIB-SEM and PIXE probe observations, indicate that most of the Pt is associated with either As-or trace Cu-Ni-rich sulfides, or both. Some of the Pt-As grains can be identified as sperrylite, and most are likely to be Pt-Fe alloy. The relative abundances and volumes of Pt minerals to sulfide minerals are very large compared with typical magmatic sulfides. Almost all of the grains observed lie at or within a few tens of mu m of cumulus orthopyroxene grain boundaries, and there is no significant difference between the populations of grains located inside or outside plagioclase oikocrysts. These oikocrysts are inferred to have crystallized either at the cumulus stage or very shortly thereafter, on the basis of their relationship to Ti enrichment in the margins of pyroxene grains not enclosed in oikocrysts. This relationship precludes a significant role of trapped intercumulus liquid in Pt deposition or mobilization and also allows a confident inference that Ptrich and Pt-As-enriched phases precipitated directly from the magma at the cumulus stage. These observations lead to the conclusion that fractionation of Pt from other PGEs in this magmatic system is a consequence of a solubility limit for solid Pt metal and/or Pt arsenide.
机译：Monts de Cristal火成岩复合物中不常见的富含Pt的辉石矿床，其特征在于Pt与其他铂族元素（PGEs）的比例异常高，而Cu和硫化物的含量却非常低。同步加速器X射线荧光显微镜用于鉴定一百多种离散的铂矿物质，并将它们的出现与宿主杂堆积的正火辉石中的组织关联相关。由FIB-SEM和PIXE探针观察支持的元素缔合表明，大多数Pt与As-或痕量的富含Cu-Ni的硫化物或两者都有关联。可以将某些Pt-As晶粒识别为锂辉石，并且大多数可能是Pt-Fe合金。与典型的岩浆硫化物相比，Pt矿物相对于硫化物矿物的相对丰度和体积非常大。几乎所有观察到的晶粒都位于斜生正丁烯积云的几十微米之内或几十微米之内，位于斜长石蛇纹石内部或外部的晶粒种群之间没有显着差异。根据它们与积聚在未包埋在辉石晶界中的辉石颗粒边缘的Ti富集的关系，可以推断这些闪锌矿在积云阶段或之后不久就已经结晶。这种关系排除了积聚的积云间液体在Pt沉积或动员中的重要作用，并且还可以有把握地推断Ptrich和富Pt-As富集相直接在积云阶段从岩浆中沉淀出来。这些观察结果得出这样的结论：在该岩浆系统中Pt与其他PGE的分离是固体Pt金属和/或Pt砷化物溶解度极限的结果。

著录项

相似文献

  • 外文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号