文献知网节
  • 记笔记
摘要:The microstructures, major-and trace-element compositions of minerals and electron backscattered diffraction(EBSD) maps of high-and low-Cr# [spinel Cr# = Cr3+/(Cr3++Al3+)] chromitites and dunites from the Zedang ophiolite in the Yarlung Zangbo Suture(South Tibet) have been used to reveal their genesis and the related geodynamic processes in the Neo-Tethyan Ocean.The high-Cr#(0.77-0.80) chromitites(with or without diopside exsolution) have chromite compositions consistent with initial crystallization by interaction between boninitic magmas, harzburgite and reaction-produced magmas in a shallow, mature mantle wedge. Some high-Cr# chromitites show crystal-plastic deformation and grain growth on previous chromite relics that have exsolved needles of diopside. These features are similar to those of the Luobusa high-Cr#chromitites, possibly recycled from the deep upper mantle in a mature subduction system. In contrast,mineralogical, chemical and EBSD features of the Zedang low-Cr#(0.49-0.67) chromitites and dunites and the silicate inclusions in chromite indicate that they formed by rapid interaction between forearc basaltic magmas(MORB-like but with rare subduction input)and the Zedang harzburgites in a dynamically extended,incipient forearc lithosphere. The evidence implies that the high-Cr# chromitites were produced or emplaced in an earlier mature arc(possibly Jurassic), while the low-Cr# associations formed in an incipient forearc during the initiation of a new episode of Neo-Tethyan subduction at ~130-120 Ma. This two-episode subduction model can provide a new explanation for the coexistence of high-and low-Cr# chromitites in the same volume of ophiolitic mantle.
会议名称:

The 4th IGCP-649 Diamonds and Recycled Mantle Workshop and Field Trip

会议时间:

2018-07-05

会议地点:

澳大利亚昆士兰州布里斯班

  • 专辑:

    基础科学; 工程科技Ⅰ辑

  • 专题:

    地质学; 地质学; 矿业工程

  • DOI:

    10.26914/c.cnkihy.2018.003275

  • 分类号:

    P587;P618.3

  • 手机阅读
    即刻使用手机阅读
    第一步

    扫描二维码下载

    "移动知网-全球学术快报"客户端

    第二步

    打开“全球学术快报”

    点击首页左上角的扫描图标

    第三步

    扫描二维码

    手机同步阅读本篇文献

  • CAJ下载
  • PDF下载

下载手机APP用APP扫此码同步阅读该篇文章

下载:2 页码:41 页数:1 大小:92k

引文网络
  • 参考文献
  • 引证文献
  • 共引文献
  • 同被引文献
  • 二级参考文献
  • 二级引证文献
  • 批量下载
相关推荐
  • 相似文献
  • 读者推荐
  • 相关基金文献
  • 相关法规
  • 关联作者
  • 相关视频