新疆阿尔泰阿舍勒VHMS型铜锌矿床成矿流体的氦——氩同位素示踪  

Helium and Argon Isotopes Tracing for Sources of Ore-forming Fluid in the Ashele Volcanogenic-host Massive Sulfide Copper—Zinc Deposit,Chinese Altay

作　　者：张志欣[1] 杨富全[2] 刘锋[2] 李强[2] 耿新霞[2] 

机构地区：[1]中国科学院新疆生态与地理研究所新疆矿产资源研究中心,乌鲁木齐830011 [2]中国地质科学院矿产资源研究所国土资源部成矿作用与资源评价重点实验室,北京100037

出　　处：《地质论评》2014年第1期222-230,共9页Geological Review

基　　金：国土资源部公益性行业科研专项经费项目(编号200911007-06);国家科技支撑计划项目(编号2011BAB06B03-02);国家自然科学基金资助项目(编号41272103)的成果

摘　　要：阿舍勒大型铜锌矿是我国典型的海相火山岩块状硫化物（VHMS）型矿床，赋存于阿舍勒盆地早一中泥盆世阿舍勒组海相火山一沉积岩系中。1号主矿体呈似层状或大透镜体状，矿石呈块状、浸染状、条带状、层纹状、细脉状。本文对块状、浸染状、条带状矿石的黄铁矿中流体包裹体He和Ar同位素进行了研究。黄铁矿中流体包裹体的。He含量为（64．5～173．0）×10-7cm-3STP／g，n（3He）／n（4He）值为（0．1358～0．379）Ra，幔源He的含量为1．79％～5．55％，表明成矿流体中He主要来源于地壳。40Ar含量为（0．318～4．69）×10-7cm3STP／g，n（40Ar）／n（36Ar）值变化于389．1～9425，40Ar＊含量为24．06％-96．89％，表明成矿流体中存在含有放射性成因Ar的海水加入。结合矿床的氢、氧、硫同位素特征，认为成矿流体来源为海水和幔源岩浆热液。The Ashele large-scale copper--zinc deposit is a typical volcanogenic massive sulfide deposit in China, which is hosted in the marine volcaniclastic--sedimentary sequence of the Early to Middle Devonian Ashele Formation. No. I orebody occurs as stratoid or large lenticular. The structures of ores are massive, disseminated, ribboned, banded and veinlet. In this paper, we analyzed the helium and argon isotopic compositions of fluid inclusions in pyrite from massive, disseminated, ribboned ores. The 4He content vary from 64.5 × 10-Tcm3STP/g to 173.0 ×l0-Tcm3STP/g, the n（3He）/n（4He） ratios are 0. 1358 Ra to 0. 379 Ra, and the contents of He derived from mantle vary from 1.79% to 5.55%, all of these characteristics suggest that the He in ore-forming fluids should mainly be derived from crust. The 4~Ar content vary from 0. 318 × 10-7 cm3STP/g to 4.69 × 10-7 cm3STP/g, the n（40Ar）/n（36Ar） ratios are 389.1 to 9425 ,and the 40Ar＊ content vary from 24.06% to 96.89%, indicate the existence of seawater in ore-forming fluids, which contain radioactive Ar. Combining hydrogen, oxygen and sulfur isotopic characteristics of the Ashele copper-zinc deposit, it can be concluded that the ore-forming fluids were a mixture between crustal-derived seawater and mantle-derived magmatic fluid, and the crustal-derived seawater is dominated.

关 键 词：He和Ar 黄铁矿 成矿流体 VHMS铜锌矿 新疆阿舍勒 

分 类 号：P597[天文地球—地球化学]