• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Journal of Asian earth sciences >A synthesis of mineralization styles with an integrated genetic model of carbonatite-syenite-hosted REE deposits in the Cenozoic Mianning-Dechang REE metallogenic belt, the eastern Tibetan Plateau, southwestern China
【24h】

A synthesis of mineralization styles with an integrated genetic model of carbonatite-syenite-hosted REE deposits in the Cenozoic Mianning-Dechang REE metallogenic belt, the eastern Tibetan Plateau, southwestern China

机译：青藏高原东部新生代绵宁-德昌稀土矿成矿带碳酸盐-硒沸石稀土矿床成矿模式综合成矿样式

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

The Cenozoic Mianning-Dechang (MD) rare earth element (REE) belt in eastern Tibet is an important source of light REE in southwest China. The belt is 270 km long and 15 km wide. The total REE resources are >3 Mt of light rare earth oxides (REO), including 3.17 Mt of REO at Maoniuping (average grade = 2.95 wt.%), 81,556 t at Dalucao (average grade = 5.21 wt.%), 0.1 Mt at Muluozhai (average grade = 3.97 wt.%), and 5764 t of REO at Lizhuang (average grade = 2.38 wt.%). Recent results from detailed geological surveys, and studies of petrographic features, ore -forming ages, ore forming conditions, and wallrock alteration are synthesized in this paper. REE mineralization within this belt is associated with carbonatite-syenite complexes, with syenites occurring as stocks intruded by carbonatitic sills or dikes. The mineralization is present as complex vein systems that contain veinlet, stringer, stockwork, and brecciated pipe type mineralization. Carbonatites in these carbonatite-related REE deposits (CARDs) are extremely rich in light REEs, Sr (>5000 ppm), and Ba (>1000 ppm), and have low Sr/Ba and high Ba/Th ratios, and radiogenic Sr-Nd isotopic compositions. These fertile magmas, which may lead to the formation of REE deposits, were generated by the partial melting of sub-continental lithospheric mantle (SCLM) that was metasomatized by REE-and CO2-rich fluids derived from subducted marine sediments. We suggest that this refertilization occurred along cratonic margins and, in particular, at a convergent margin where small-volume carbonatitic melts ascended along trans-lithospheric faults and transported REEs into the overlying crust, leading to the formation of the CARDs. The formation of fertile carbonatites requires a thick lithosphere and/or high pressures (>25 kbar), a metasomatized and enriched mantle source, and favorable pathways for magma to ascend into the overlying crust where REE-rich fluids exsolve from cooling magma. The optimal combination of these three factors only occurs along the margins of a craton with a continental root, rather than in modern subduction zones where the lithosphere is relatively thin.
机译：西藏东部的新生代绵宁-德昌（MD）稀土元素带是中国西南部重要的轻稀土元素来源。该带长270公里，宽15公里。稀土资源总量> 3 Mt轻稀土氧化物（REO），包括毛牛坪的3.17 Mt REO（平均品位= 2.95 wt。％），Dalucao的81,556 t（平均品位= 5.21 wt。％），0.1 Mt Muluozhai（平均品位= 3.97 wt。％）和Lizhuang（平均品位= 2.38 wt。％）5764 t REO。本文综合了详细的地质调查和岩石学特征，成矿年龄，成矿条件和围岩蚀变的研究成果。该带内的REE矿化与碳酸盐-硒酸盐复合物有关，由于碳酸盐基岩或堤防侵入，这些硒酸盐以储量形式出现。矿化是复杂的静脉系统，其中包含小矿脉，纵梁，储层和角铁管型矿化。这些与碳酸盐岩有关的REE矿床（CARD）中的碳酸盐岩中的轻稀土，Sr（> 5000 ppm）和Ba（> 1000 ppm）极其丰富，并且Sr / Ba和Ba / Th的比例低，并且放射性Sr-钕同位素组成。这些肥沃的岩浆可能是由次大陆岩石圈地幔（SCLM）的部分融化而产生的，这些沉积物是由俯冲的海洋沉积物中富含REE和CO2的流体交代的。我们建议这种倾斜作用是在克拉通边缘发生的，特别是在会聚边缘，小量的碳酸盐岩熔体沿着跨岩圈断层上升，并将REEs运到上覆地壳中，从而形成了CARDs。肥沃的碳酸盐岩的形成需要较厚的岩石圈和/或高压（> 25 kbar），交代并富集的地幔源，以及有利的岩浆进入上覆地壳的途径，富含REE的流体从冷却岩浆中溶解。这三个因素的最佳组合仅出现在具大陆根的克拉通边缘，而不是岩石圈相对薄的现代俯冲带。

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