...
  • 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 >Hollandite-strontiomelane solid solutions coexisting with kanonaite and braunite in late quartz veins of the Stavelot Massif, Ardennes, Belgium
【24h】

Hollandite-strontiomelane solid solutions coexisting with kanonaite and braunite in late quartz veins of the Stavelot Massif, Ardennes, Belgium

机译：在比利时阿登的斯塔韦洛地块晚期石英脉中，钙铁矿和褐铁矿中的钙铝石-锶镁铁矿固溶体共存

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

In a newly found type of quartz vein crosscutting the famous "viridine"-bearing phyllites at Le Coreux, hollandite, ideally BaMn_8O_(16), was discovered for the first time at this locality and in Belgium. Because the crystals contain up to 60 mol percent of the Sr end member, this is also the second occurrence of strontiomelane. The coexisting viridine" (= kanonaite) contains the highest amount (88 mol percent) of the ideal end member MnAlSiO_5 ever found worldwide. The hollandite-type minerals are intimately intergrown with bra-unite containing appreciable Ca and Mg. Ba-bearing muscovite, Fe-poor excess-Al clinochlore (not quite trioctahedral), and albite are the remaining accessory minerals in the dominant quartz matrix. Microprobe analyses of all phases show rather extreme element fractionations: nearly all K is located in muscovite and none in the hollandite phase despite the existence of the end member KMn_8O_(16) (cryptomelane). Similarly, nearly all Na is in albite and not in hollandite (no NaMn_8O_(16) = manjiroite component). Nearly all Mn resides in the two oxide phases and in kanonaite. Mg is strongly fractionated into chlorite. The small amounts of Fe and Ti present are predominantly partitioned into the hollandite phase, which also accommodates most of the Ba and Sr. Indeed, the hollandite phase is stabilized by the latter two elements relative to other Mn oxides. Kanonaite is stabilized by Al. Although no requisite sites are available in its crystal structure, braunite always contains small amounts of Ba and Sr. However, the Sr/(Sr + Ba) ratios in braunite are spurious and unrelated to those of the directly adjoining hollandite phases. The conditions of formation of these veins may be well below 300 deg C at low pressures (1-2 kbar), in agreement with the experimental results that the maximum Mn contents in kanonaite increase with falling temperatures.
机译：在一种新发现的石英脉中，在勒·科鲁克斯（Le Coreux）横切了著名的带有“ viridine”的花岗石，在该地区和比利时首次发现了沸石，理想的是BaMn_8O_（16）。因为晶体包含高达60 mol％的Sr端基，所以这也是锶提花的第二次出现。并存的viridine”（=钙铝石）包含世界上发现的最高量的理想端基MnAlSiO_5（88摩尔％）。该钙铝石型矿物与含大量Ca和Mg的含钙白云母的黄铜矿紧密结合，贫铁的过量铝斜绿石（不完全是八面体）和钠长石是占主导地位的石英基体中剩余的辅助矿物，所有相的微探针分析均显示出极高的元素分馏：几乎所有K都位于白云母中，而钾铁矿中则没有尽管存在末端成员KMn_8O_（16）（隐藻石）。类似地，几乎所有的Na都在钠长石中而不是在辉石中（没有NaMn_8O_（16）=锰铁矿组分）。几乎所有的Mn都存在于两个氧化物相和卡诺诺石中。镁被强烈地分离成绿泥石，少量的铁和钛主要被分配到钙铁矿相中，而钙铁矿相也可以容纳大部分的钡和锶。相对于其他Mn氧化物，后两种元素稳定了S。金铝石被Al稳定化。尽管在其晶体结构中没有必要的位点，但褐铁矿总是含有少量的Ba和Sr，但是，褐铁矿中Sr /（Sr + Ba）的比率是虚假的，与直接毗邻的堇青石相的比率无关。这些静脉的形成条件在低压（1-2 kbar）下可能远低于300摄氏度，这与实验结果一致，即金诺石中的最大Mn含量随温度降低而增加。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 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