华北克拉通金伯利岩型金刚石矿床含矿性判别
作者:
作者单位:

作者简介:

通讯作者:

中图分类号:

基金项目:

本文为中国地质调查局地质调查工作项目(编号12120114027901)资助成果。


Evaluating the diamond potential of kimberlite- hosted diamond deposits from the North China Craton
Author:
Affiliation:

Fund Project:

  • 摘要
  • |
  • 图/表
  • |
  • 访问统计
  • |
  • 参考文献
  • |
  • 相似文献
  • |
  • 引证文献
  • |
  • 资源附件
  • |
  • 文章评论
    摘要:

    金伯利岩型金刚石原生矿床含矿性评价是了解金刚石成矿规律和指导区域性找矿的重要依据。华北克拉通是我国重要的金刚石成矿远景区,目前已发现了两个重要的含金刚石金伯利岩岩区(山东蒙阴和辽宁瓦房店)。近年来,对岩区内不同品位金刚石典型矿床的研究表明金伯利岩中的金刚石品位取决于以下两个重要的地质过程:金伯利岩岩浆对金刚石的捕获作用和金伯利岩岩浆对金刚石的熔蚀作用。在华北克拉通下方存在一个金刚石稳定区,温度为950~1200 ℃,压力为4. 4~6. 1 GPa。山东蒙阴和辽宁瓦房店金伯利岩岩浆在上升过程中穿过该区域并捕获其中的金刚石,成为含矿岩浆;而铁岭和鹤县等金伯利岩岩浆在上升过程中不穿过该区域,成为不含矿岩浆。在穿过金刚石稳定区时,富矿的金伯利岩捕获了更多的金刚石以及金刚石的伴生指示矿物(如镁铝榴石,镁铬铁矿);而贫矿的金伯利岩则相对捕获了少量的金刚石和指示矿物。这些指示矿物往往参加了金刚石的形成过程,有些作为缓冲剂控制了反应(岩浆或熔体)的氧化还原状态,有些则作为反应物或者生成物参与到反应中。部分指示矿物(如镁铝榴石)还进一步地记录了金刚石形成后金伯利岩岩浆对金刚石的交代作用。金伯利岩岩浆温度(T),氧逸度(fO2)和挥发份(H2O和CO2)均会对金刚石的熔蚀作用产生影响,其中氧逸度作用最大,温度次之,而挥发份作用最弱。在华北克拉通,金伯利岩中指示矿物(镁铝榴石、镁铬铁矿)和金伯利岩岩浆特征(温度,氧逸度和挥发份)共同组成了金伯利岩型金刚石原生矿的评价指标。

    Abstract:

    The diamond potential evaluation of kimberlite- hosted primary diamond deposit is important for understanding of diamond metallogenic rule and guiding regional diamond prospecting. The North China Craton is an important region for diamond prospecting in China. At present, two important diamond- bearing kimberlite areas have been found in Mengyin (Shandong Province) and Wafangdian (Liaoning Province). In recent years, the study of typical diamond deposits of different diamond grades shows that the diamond grades in the kimberlite depend on the following two important geological processes: the capture of diamond by kimberlite magma, and the dissolution of diamond by kimberlite magma. A diamond stability field at a temperature of 950~1200 ℃ and pressure of 4. 4~6. 1 GPa beneath the North China craton has been proposed. The kimberlitic magma in the Mengyin and the Wafangdian areas passed through the diamond stability field and captured the diamonds during its ascent, and hence become diamondiferous; while the kimberlitic magma in the Tieling and the Hexian areas did not pass through the field, and therefore are barren. As it passed through the diamond stabilization zone, high- grade diamondiferous kimberlite captured more diamonds and indicator minerals that occur with diamond (e. g. , pyrope garnet, magnesia- chromite). The low- grade diamondiferous kimberlites capture relatively fewer indicator minerals. These indicator minerals are often involved in diamond formation, some as buffers to control the redox state of the reaction (magma or melt), and some as reactants or products that participate in the reaction. Some indicator minerals (e. g. , magnesia- aluminum garnet) further document the metasomatism process by kimberlite magma to diamond after diamond formation. The temperature (T), oxygen fugacity (fO2) and volatiles (H2O and CO2) of kimberlite magma influences the dissolution process of diamond. Amongst these oxygen fugacity’s effect is strongest, temperature’s effect is weaker, and volatile’s effect is the weakest. In the North China Craton, the indicator minerals in kimberlite (pyrope garnet, magnesia chromite) and kimberlite magma parameters (temperature, oxygen fugacity, and volatiles) together constitute the evaluation index of kimberlite diamond primary deposit.

    参考文献
    相似文献
    引证文献
引用本文

倪培,朱仁智.2020.华北克拉通金伯利岩型金刚石矿床含矿性判别[J].地质学报,94(9):2557-2573.
NI Pei, ZHU Renzhi.2020. Evaluating the diamond potential of kimberlite- hosted diamond deposits from the North China Craton[J]. Acta Geologica Sinica,94(9):2557-2573.

复制
分享
文章指标
  • 点击次数:
  • 下载次数:
  • HTML阅读次数:
  • 引用次数:
历史
  • 收稿日期:2020-04-25
  • 最后修改日期:2020-07-28
  • 录用日期:2020-07-28
  • 在线发布日期: 2020-07-29
  • 出版日期: