黄铁矿稀土元素和微量元素地球化学特征:对东准噶尔绿源金矿成矿流体的约束  

Geochemical Characteristics of REE and Trace Elements of Pyrite:Constraint on the Ore-Forming Fluid of the Lvyuan Gold Deposit,Eastern Junggar

作　　者：元强[1] 葛文胜[1] 丁辉[1] 陈疆[2] 贾红旭[2] 黄钢[1] 张佳儒[2] 

机构地区：[1]中国地质大学(北京)地球科学与资源学院地质过程与矿产资源国家重点实验室,北京100083 [2]新疆维吾尔自治区地质矿产勘查开发局第六地质大队,新疆哈密839000

出　　处：《矿物岩石地球化学通报》2017年第4期628-636,共9页Bulletin of Mineralogy, Petrology and Geochemistry

基　　金：新疆地质矿产勘查开发局项目(DZKC201504-009)

摘　　要：为探讨东准噶尔绿源金矿成矿流体性质及其演化特征,以矿床中的载金黄铁矿为研究对象,运用ICP-MS方法,研究了黄铁矿中的稀土元素和微量元素地球化学特征。结果显示,黄铁矿具有轻重稀土分馏较明显、轻稀土元素富集的右倾配分模式,其Hf/Sm、Th/La和Nb/La值均小于1;富集Cu、Pb、Zn、Cd、Sb等亲硫元素,具有较弱的Ce负异常。上述特征表明,成矿过程的物理化学条件为还原环境,成矿Ⅰ、Ⅱ阶段流体的温度低,成矿Ⅲ阶段可能混入外来热液,导致流体温度升高。黄铁矿的Y/Ho值、Zr/Hf值和Nb/Ta值较大的变化范围表明成矿热液以早期流体为主,并可能与弧后盆地关系密切。Geochemical characteristics of REE and trace elements of the gold-bearing pyrite were studied by applying ICPMS method to discuss properties and evolution characteristics of the ore-forming fluid in the Lvyuan gold deposit,eastern Junggar. Results show that the pyrite has right-declined REE distribution patterns,with relatively obvious LREE/HREE fractionation and LREE enrichment. Its Hf/Sm,Th/La and Nb/La values are all lower than 1. These indicate that the oreforming fluid is enriched in Cl-. In addition,pyrite also has enriched in chalcophile elements including Cu,Pb,Zn,Cd and Sb. The weak Ce anomaly of its REE patterns indicates that the Au mineralization occurred in the reduced environment. The variation characteristics of δEu and Co/Ni values of Stage Ⅰ,Ⅱ,Ⅲ pyrites indicate that temperatures of oreforming fluids in Stage Ⅰ and Ⅱ are relatively low,while the temperature of the ore-forming fluid in Stage III is relatively high,probably due to the mixing of external hydrothermal fluid. The wide ranges of Y/Ho,Zr/Hf and Nb/Ta values of pyrites indicate that the Au mineralization occurred mostly in the early stage ore-forming fluid which could be closely related to the back-arc basin.

关 键 词：黄铁矿 稀土元素 微量元素 成矿流体 绿源金矿 东准噶尔 

分 类 号：P595[天文地球—地球化学] P618.51[天文地球—地质学]