青藏高原东缘斑岩铜钼金成矿带的构造模式
DOI:
作者:
作者单位:

作者简介:

通讯作者:

中图分类号:

基金项目:

国家重点基础研究发展规划“973”项目(2002CB412600)资助。


A tectonic model for porphyry copper-molybdenum-gold metallogenic belts on the eastern margin of the Qinghai-Tibet Plateau
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:

    提要:在印度—亚洲大陆碰撞形成的青藏高原东缘, 伴随着高钾富碱斑岩的浅成侵位, 发育 “成对”出现的、受大规模走滑断裂控制的新生代陆内斑岩铜钼金成矿带, 其中西带为江达—芒康—祥云铜钼金成矿带, 东带为中甸—盐源—姚安斑岩铜金铅银成矿带。含矿斑岩岩石类型为花岗斑岩、二长花岗斑岩、二长斑岩和少量正长斑岩, 以较高的SiO2(>63%)和较低的Y(<20×10-6)区别于非含矿斑岩, 并具有似埃达克岩(adakite-like)岩浆亲合性。富碱斑岩相对富集LILE (K、Rb、Ba) 、亏损HFSE (Nb、Ta、Ti、P), Nb/Y比值具有较大的变化范围, REE分馏强烈但不出现明显的负Eu异常, 反映岩浆源区曾经历过古俯冲洋壳板片流体的交代富集作用和软流圈小股熔融体的注入。含矿的似埃达克斑岩可能源于玄武质下地壳, 后者经历高压(>40 km)下角闪岩-榴辉岩相变质和板片流体交代, 并作为下地壳角闪岩包体在富碱斑岩中出现;不含矿的正长斑岩可能起源于含水的金云母橄榄岩富集地幔。微量元素和Sr-Nd-Pb同位素系统反映, 该源区遭受了更强烈的板片流体交代和软流圈物质混染。深部地球物理探测资料表明, 50 Ma以来的扬子大陆板片向西俯冲, 并与印度大陆俯冲板片对挤, 诱发了软流圈上涌热蚀及其熔融体的底侵注入, 引起了壳幔过渡带的部分熔融。似埃达克斑岩岩浆以相对富水、富S和高氧逸度(fo2)特征, 成为成矿金属和硫的重要载体, 并在浅位封闭系统形成斑岩铜钼金矿床。

    Abstract:

    Abstract:Accompanied by hypabyssal emplacement of high-potassic alkali-rich porphyries, “paired” Cenozoic intracontinental porphyry copper-molybdenum-gold belts, controlled by large strike-slip faults, occurred on the eastern margin of the Qinghai-Tibet Plateau formed by India-Asia collision. Of the two metallogenic belts, the west belt is the Jomda-Markam-Xiangyun copper-molybdenum belt and the east belt is the Zhongdian-Yanyuan-Yao'an porphyry copper-gold-lead-silver belt. The rock types of ore-bearing porphyry include granite porphyry, monzogranite porphyry and monzonite porphyry with small amount of syenite porphyry. They are distinguished from barren porphyry by their higher SiO2 (>63%) and lower Y (<20×10-6) and their adakitic magma affinity. Alkali-rich porphyry is relatively enriched in large-ion lithophile elements (K, Rb and Ba) and depleted in high-field strength elements (Nb, Ta, Ti and P) with a wider range of Nb/Y ratios and shows strong REE fractionation but no pronounced negative Eu anomaly—all these suggest that the magma source region underwent metasomatism and concentration of ancient subducted oceanic slab fluids and was injected by small streams of melts from the asthenosphere. Ore-bearing adakite-like porphyry might originate from the basaltic lower crust. The latter underwent high-pressure (>40 km) low amphibolite-eclogite facies metamorphism and slab fluid metasomatism and occurs as lower-crustal amphibolite xenoliths in alkali-rich porphyry. Barren syenite porphyry might originate from the hydrated phologopite peridotite-enriched mantle. Its trace element and Su-Nd-Pb isotope systematics indicate that their source region was subjected to much stronger slab fluid metasomatism and mixing of asthenospheric material. Available data of deep geophysical exploration suggest that since 50 Ma BP the Yangtze continental slab was subducted westwards and collided with the subducted Indian continental slab, thus inducing upwelling, thermal erosion and underplating of asthenospheric melts and giving rise to partial melting of the crust-mantle transition zone. The magma of adakite-like porphyry is characterized by the presence of relatively rich water, rich sulfur and higher oxygen fugacity (fo2). It was an important metal and sulfur carrier and formed porphyry copper-gold-lead-silver deposits in a shallow-level closed system.

    参考文献
    相似文献
    引证文献
引用本文

侯增谦 钟大赉 邓万明. 青藏高原东缘斑岩铜钼金成矿带的构造模式[J]. 中国地质, 2004, 31(1): 1-14.
HOU Zeng-qian, ZHONG Da-lai, DENG Wan-ming. A tectonic model for porphyry copper-molybdenum-gold metallogenic belts on the eastern margin of the Qinghai-Tibet Plateau[J]. Geology in China, 2004, 31(1): 1-14(in Chinese with English abstract).

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:
  • 最后修改日期:
  • 录用日期:
  • 在线发布日期: 2013-04-12
  • 出版日期:
亮点文章推荐
古人云:工欲善其事,必先利其器。我国新一轮战略找矿行动已全面启动。用什么方法、什么手段实现增储上产是面临的突出问题。本刊登载了几篇基于新技术、新方法实现找矿突破的实例,供大家参阅,助力新一轮战略找矿目标的实现。
基于随机森林算法的找矿预测——以冈底斯成矿带西段斑岩—浅成低温热液型铜多金属矿为例. 欧阳渊等,2023, 50(2):303-330.
基于重磁资料在山东齐河—禹城探获矽卡岩型富铁矿:对超深覆盖区找矿的启示. 王润生等,2023, 50(2):331-346.
自然伽马曲线重构波阻抗反演在勘探含铀有利成矿砂体中的尝试. 梁建刚等,2023, 50(2):347-358.
宽频大地电磁法寻找“界面型”隐伏金矿床:以黔西南戈塘地区深部找矿为例. 张伟等,2023, 50(2):359-375.
页岩气基础地质调查钻井技术研究进展及展望. 赵洪波等,2023, 50(2):376-394.
关闭