...
  • 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 >Tourmaline geochemistry and δ11B variations as a guide to fluid–rock interaction in the Habachtal emerald deposit, Tauern Window, Austria
【24h】

Tourmaline geochemistry and δ11B variations as a guide to fluid–rock interaction in the Habachtal emerald deposit, Tauern Window, Austria

机译：电气石地球化学和δ 11 B的变化，作为奥地利陶恩窗口Habachtal祖母绿矿床中流体-岩石相互作用的指南

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

Tourmalines from the Habachtal emerald deposit in the Eastern Alps formed together with emerald in a ductile shear zone during blackwall metasomatism between pelitic country rocks and a serpentinite body. Electron microprobe and secondary ion mass spectrometric (SIMS) analyses provide a record of chemical and B-isotope variations in tourmalines which represent an idealized profile from metapelites into the blackwall sequence of biotite and chlorite schists. Tourmaline is intermediate schorl-dravite in the country rock and become increasingly dravitic in the blackwall zones, while F and Cr contents increase and Al drops. Metasomatic tourmaline from blackwall zones is typically zoned optically and chemically, with rim compositions rich in Mg, Ti, Ca and F compared with the cores. The total range in δ11B values is −13.8 to −5.1‰ and the within-sample variations are typically 3–5‰. Both of these ranges are beyond the reach of closed-system fractionation at the estimated 500–550°C conditions of formation, and at least two boron components with contrasting isotopic composition are indicated. A key observation from tourmaline core analyses is a systematic shift in δ11B from the country rock (−14 to −10‰) to the inner blackwall zones (−9 to −5‰). We suggest that two separate fluids were channeled and partially mixed in the Habachtal shear zone during blackwall alteration and tourmaline-emerald mineralization. A regional metamorphic fluid carried isotopically light boron as observed in the metapelite country rocks. The other fluid is derived from the serpentinite association and has isotopically heavier boron typical for MORB or altered oceanic crust. Keywords SIMS - B-isotopes - Tourmaline - Sector zoning - Blackwall alteration - Eastern Alps Communicated by J. Hoefs.
机译：东部阿尔卑斯山的哈巴克塔尔祖母绿矿床中的电气石是在球状乡村岩石和蛇纹岩体之间的黑壁交代作用期间，在韧性剪切带中与祖母绿一起形成的。电子微探针和二次离子质谱（SIMS）分析提供了电气石中化学和B同位素变化的记录，代表了从变石到黑云母和绿泥石片岩的黑墙序列的理想轮廓。电气石在乡村岩石中是中间的cho草晶，在黑墙带中逐渐变硬，而F和Cr含量增加而Al下降。来自黑墙带的交代电气石通常在光学和化学上进行了分区，与核相比，其轮缘成分富含Mg，Ti，Ca和F。 δ 11 B值的总范围为-13.8至-5.1‰，样本内变化通常为3-5‰。在估计的500–550°C形成条件下，这两个范围都超出了封闭系统分馏的范围，并指出了至少两种具有相反同位素组成的硼组分。电气石岩心分析的主要观察结果是δ 11 B从乡村岩石（−14至-10‰）到内部黑墙带（−9至−5‰）的系统转移。我们建议在黑壁蚀变和电气石祖母绿矿化过程中，在哈巴克塔尔剪切带中引导并部分混合两种流体。在变质岩乡村岩石中观察到，区域变质流体携带同位素轻硼。其他流体来自蛇纹岩结合体，并且具有同位素重的硼，通常用于MORB或改变的海洋地壳。关键字SIMS-B同位素-电气石-区域分区-黑墙蚀变-东阿尔卑斯山由J. Hoefs沟通。

著录项

相似文献

  • 外文文献
  • 中文文献
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