...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Lithos: An International Journal of Mineralogy, Petrology, and Geochemistry >UHP kyanite eclogite associated with garnet peridotite and diamond-bearing granulite, northern Bohemian Massif
【24h】

UHP kyanite eclogite associated with garnet peridotite and diamond-bearing granulite, northern Bohemian Massif

机译：波希米亚地块北部的UHP蓝晶石榴辉岩与石榴石橄榄岩和含金刚石的粒状岩

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

Kyanite eclogites enclosed in garnet peridotites may provide important information on P-T evolution of orogenic peridotites in deep subduction and collision zones. Kyanite eclogite interlayered with garnet peridotite occurs in the borehole T-7, in the Saxothuringian basement of the northern part of the Bohemian Massif. This orogenic peridotite of mantle origin is associated with felsic granulites, which contain diamond as a consequence of deep subduction of the continental crust. Here, we report on the metamorphic evolution of kyanite eclogite, which shows a well-preserved peak-pressure mineral assemblage of garnet, omphacite, kyanite and phengite. Conventional geothermobarometry, average PT method and thermodynamic modelling constrain the metamorphic conditions of this assemblage up to 3.5-4.5 GPa at 900-1050 degrees C. Two compositional types of garnet, i.e., Mg-rich and Ca-rich, have been recognised. Thermodynamic modelling shows that the composition of Ca-rich garnet with X-Ca (0.35-037) in the core corresponds to stability of garnet at 3.5-4.5 GPa. Amphibole and zoisite are preserved as inclusions in garnet cores, and they are stable below 2.5 GPa, indicating that garnet grew at the expense of these phases at increasing P-T conditions during the prograde evolution of the rock. A post-peak metamorphism decompression and cooling are recorded by decrease of Ca-Eskola end-member in omphacite, drop in X-Mg and X-Grs at garnet rim and a very restricted formation of pargasitic amphibole in the matrix. The absence of symplectites after omphacite in the investigated eclogite may be due to a very low content of quartz and possibly also fluid in the rock. Our study suggests that kyanite-bearing eclogite underwent UHP metamorphism as a consequence of subduction, together with interlayered garnet peridotite. Both rocks were incorporated into the subducted continental crust (diamond-bearing granulites) during the Variscan orogeny. (C) 2015 Elsevier B.V. All rights reserved.
机译：包围在石榴石橄榄岩中的蓝晶岩榴辉岩可能提供有关深俯冲和碰撞带造山橄榄岩P-T演化的重要信息。在波西米亚地块北部北部萨克斯图林基底的T-7钻孔中，夹有石榴石橄榄岩的蓝晶岩榴辉岩。地幔起源的造山橄榄岩与长英质花岗石有关，后者是由于大陆壳深层俯冲的结果而含有钻石的。在这里，我们报道了蓝晶石榴辉岩的变质演化，表明石榴石，绿辉石，蓝晶石和锂铁矿的峰压矿物组合保存得很好。常规的地热大气压力法，平均PT法和热力学模型将这种组合的变质条件限制在900-1050摄氏度下高达3.5-4.5 GPa。已经认识到石榴石的两种成分类型，即富含Mg和富含Ca的石榴石。热力学建模表明，在芯中具有X-Ca（0.35-037）的富含Ca的石榴石的组成与石榴石在3.5-4.5 GPa时的稳定性相对应。闪石和膨润土被保留为石榴石核心中的内含物，并且在2.5 GPa以下时保持稳定，表明石榴石在岩石的渐进演化过程中，随着P-T的增加，以这些相为代价生长。峰后变质作用的减压和冷却是通过辉绿岩中Ca-Eskola末端成员的减少，石榴石边缘处X-Mg和X-Grs的下降以及基体中胃气管闪石的形成非常受限制而记录的。在研究的榴辉岩中，在辉绿岩之后不存在共沸物，可能是由于石英的含量非常低，而且岩石中也可能存在流体。我们的研究表明，由于俯冲作用，含蓝晶石的榴辉岩与层状石榴石橄榄岩一起经历了超高压变质作用。在Variscan造山运动中，这两种岩石都被整合到俯冲的大陆壳（含金刚石的花岗石）中。 （C）2015 Elsevier B.V.保留所有权利。

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