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现代地质 ›› 2011, Vol. 25 ›› Issue (2): 261-270.

• 矿床学与同位素地球化学 • 上一篇    下一篇

川西甘孜—理塘金矿带形成条件的矿物电子探针与裂变径迹研究

郇伟静,袁万明,李娜   

  1. 地质过程与矿产资源国家重点实验室 中国地质大学 地球科学与资源学院, 北京100083
  • 出版日期:2011-04-25 发布日期:2011-05-13
  • 通讯作者: 袁万明,男,教授,1956年出生,矿物学、岩石学、矿床学专业,主要从事裂变径迹技术的地学应用研究。
  • 作者简介:郇伟静,男,硕士研究生,1987年出生,矿物学、岩石学、矿床学专业,主要从事矿物标型研究。 Email:huanweijing@126.com
  • 基金资助:

    国家重点基础研究发展计划“973”项目(2009CB421006);教育部“111计划”项目(B07011);中国地质大学地质过程与矿产资源国家重点实验室项目

Study on the Mineral Electron Microprobe Evidence of the Formation  Conditions and Fission Track of Gold Deposits in Ganzi-Litang Gold  Belt, Western Sichuan Province

HUAN WEI -Jing,YUAN  Wango-Ming,LI  Na   

  1. State Key Laboratory of Geological Processes and Mineral Resources, School of Earth Sciences and Resources, China University of Geosciences, Beijing100083, China
  • Online:2011-04-25 Published:2011-05-13

摘要:

甘孜—理塘金矿带位于青藏高原东部松潘—甘孜造山带与义敦岛弧造山带的交界部位。通过对嘎拉、错阿、雄龙西、阿加隆洼和曲开隆洼等5个金矿区矿石样品中主要载金矿物黄铁矿和毒砂的电子探针分析,试图探讨区内金矿形成温度、深度和成生环境,并结合矿石锆石裂变径迹定年探讨成矿代。研究区黄铁矿为S亏损型,普遍含Co和Ni,含量分别为0.04%~1.73%和0.01%~2.97%,其中w(Co)均值为0.43%, w(Co)/w(Ni)值为0.08~10.04, 均值为2.28。w(Fe)/w(S+As)值为0.841~0.907,平均为0.875。毒砂表现出富S亏As的特点,w(Fe)/w(As+S)=0.49~0.57;w(As)/w(S)=0.73~0.87。总体上看,甘孜—理塘金矿床形成于氧逸度较高、中低温热液环境下,成矿温度以165~250 ℃为主,成矿部位主要为中—浅部。该金矿带的成矿时代为82~140 Ma,具有多期次特点,成矿作用与燕山期的碱性岩浆热液有关。

关键词: 电子探针分析;裂变径迹;中低温热液金矿床;甘孜&mdash, 理塘金矿带;青藏高原

Abstract:

Ganzi-Litang gold belt is located in the Eastern Qinghai-Tibet Plateau, the junction area of Songpan-Ganzi orogenic zones and Yidun arc orogen. The authors attempt to explore the ore-formating temperature, depth and environments of the five gold deposits, i.e. Gala gold ore district, Cuo-a gold ore district, Xionglongxi gold ore district, Ajialongwa gold ore district and Qukailongwa gold ore district, using electron microprobe analysis of the main goldbearing minerals of pyrite and arsenopyrite. The mineralizing age is discussed based on the fission track age of zircon in the ore. The pyrites are characteried by lossing sulfur content and generally containing cobalt and nickel,in which the content of cobalt is from 0.04% to 1.73%, and that of nickel is from 0.01% to 2.97%. The mean content of cobalt is 0.43%, and the composition ratios of Co/Ni range from 0.08 to 10.04 with an average of 2.28. The pyrites have the composition ratios of Fe/(S+As) between 0.841 and 0.907, averaging 0.875. Arsenopyrite belongs to arsenicrich sulfur type, the ratio of Fe/(As+S) is from 0.49 to 0.57 while that of As/S is from 0.73 to 0.87.Therefore, we consider that the gold deposits formed in the condition of higher oxygen fugacity, middle-shallow depths and middle-low temperature hydrotherm of 165-250℃. They are the epithermal gold deposits, and the mineralizing age of gold is between 82 and 140 Ma with a multi-stage characteristics, and the oremineralization was closely related to the alkaline magmatic hydrotherm in Yanshanian Period.

Key words: electron microprobe analysis, fission track, epithermal gold deposit, GanziLitang gold belt, Tibet Plateau

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