欢迎访问现代地质!

现代地质 ›› 2018, Vol. 32 ›› Issue (05): 874-886.DOI: 10.19657/j.geoscience.1000-8527.2018.05.02

• 岩石学与矿床学 • 上一篇    下一篇

西藏蒙亚啊铅锌矿床矽卡岩矿物特征及其意义

邬秋敏1(), 陈翠华1(), 涂宗林2, 张燕1, 宋志娇1, 赖翔1   

  1. 1.成都理工大学 地球科学学院,四川 成都 610059
    2.四川省地质矿产勘查开发局 四〇三地质队,四川 峨眉 614200
  • 收稿日期:2017-12-25 修回日期:2018-05-31 出版日期:2018-10-10 发布日期:2018-11-04
  • 通讯作者: 陈翠华,女,教授,1972年出生,地球化学专业,主要从事矿床学、矿相学、地球化学研究工作。Email:chencuihua@cdut.edu.cn
  • 作者简介:邬秋敏,女,硕士研究生,1993年出生,矿物学、岩石学、矿床学专业,主要从事矿物学、岩石学、矿床学研究。Email:820797686@qq.com
  • 基金资助:
    四川省教育厅项目(SZX040);中国地质调查局项目(12120113036200);国家自然科学基金项目(41372093)

Characteristics and Significance of Skarn Minerals of Mengya’a Pb-Zn Deposit in Tibet

WU Qiumin1(), CHEN Cuihua1(), TU Zonglin2, ZHANG Yan1, SONG Zhijiao1, LAI Xiang1   

  1. 1. College of Earth Sciences, Chengdu University of Technology, Chengdu, Sichuan 610059, China
    2. No.403 Geological Party, Sichuan Bureau of Geology and Mineral Exploration and Development,Emei, Sichuan 614200, China
  • Received:2017-12-25 Revised:2018-05-31 Online:2018-10-10 Published:2018-11-04

摘要:

西藏蒙亚啊铅锌矿床是冈底斯北缘一个重要的层状或似层状矽卡岩矿床,来姑组为矿床的主要容矿层位。矿区矽卡岩矿物主要有硅灰石、辉石、石榴石、透闪石、阳起石、绿帘石和绿泥石等。根据矿物的共生组合及交代关系,推断矿床经历了4个成矿阶段:早期矽卡岩阶段、晚期矽卡岩阶段、石英-硫化物阶段和碳酸盐阶段。结合矿物手标本及显微镜下观察,通过对矽卡岩矿物的电子探针测试,分析石榴石、辉石和硅灰石的矿物特征,结果表明:西藏蒙亚啊铅锌矿床属钙质矽卡岩矿床,石榴石和辉石的组分变化较大,分别为And59.9~94.72Gro0~37.87(Pyr+Spe+Alm)0.87~6.78和Di18.85~94.44Hd3.39~70.58Jo0.09~11.14,硅灰石的矿物组分为Wo99.00~99.44Fs0.37~0.78En0.07~0.23。石榴石属钙铁榴石-钙铝榴石系列,且环带发育,辉石为透辉石-钙铁辉石系列,硅灰石组分较纯。西藏蒙亚啊矽卡岩为钙质矽卡岩,其矿床在形成过程中经历了热液流体的多期多阶段演化,矿床形成环境也并不是稳定的封闭体系。矽卡岩矿物成分特征表明,蒙亚啊铅锌矿床的成矿环境是一个低酸性的氧化-弱氧化环境。

关键词: 成矿环境, 矽卡岩矿物特征, 蒙亚啊铅锌矿床, 西藏

Abstract:

Mengya’a lead-zinc deposit in Tibet is an important stratified or stratoid skarn deposit in the northern margin of Gangdise. Laigu Formation, the main ore-hosting strata, provides the main metallogenic material. The main skarn minerals consist mainly of wollastonite, pyroxene, garnet, hopfnerite, actinolite, epidote, chlorite etc.According to the association combination and replacement relationship of minerals, the authors infer that Mengya’a lead-zinc deposit experienced four stages, i.e., early-skarn stage, late-skarn stage, quartz-sulfide stage and carbonation stage. Combining with mineral hand specimens and microscopic observation and the electron microprobe analysis, the authors analyzed the mineralogical characteristics of garnet, pyroxene and wollastonite. The results of electron microprobe analysis show that Mengya’a lead-zinc deposit in Tibet belongs to calcareous skarn deposit; the composition of garnet and pyroxene changed greatly, which respectively were And59.9-94.72 Gro0-37.87(Pyr+Spe+Alm)0.87-6.78 and Di18.85-94.44 Hd3.39-70.58 Jo0.09-11.14; the mineral composition of wollastonite is Wo99.00-99.44Fs0.37-0.78En0.07-0.23. The garnets are mainly andradite-grossuthe, and the garnets always develop zoning structure. The pyroxene is diopside-hedenbergite series, and the wollastonite is pure. The skarn of Mengya’a deposit in Tibet is calcareous skarn. Its ore deposit experienced multi-stage and multi-order evolution of hydrothermal fluid during its formation, and the forming environment of the deposit also is not a stable close system. The mineral composition characteristics of skarn indicate that the metallogenic environment of Mengya’a Pb-Zn deposit was a low acid and oxidation-weak oxidation environment.

Key words: metallogenic environment, mineral characteristics of skarn, Mengya’a Pb-Zn deposit, Tibet

中图分类号: