青海虎头崖铅锌多金属矿床原位硫、铅同位素组成及成矿物质来源探讨  

The In-Situ Sulfur and Lead Isotopic Compositions of the Hutouya Pb-Zn Polymetallic Deposit of Qinghai Province for Discussing the Source of Its Ore-forming Materials

作　　者：张圆圆[1] 易立文 谢炳庚[1,2] 李秋平 刘程爱 于娟 ZHANG Yuan-yuan;YI Li-wen;XIE Bing-geng;LI Qiu-ping;LIU Cheng-ai;YU Juan(College of Resources and Environmental Sciences,Hunan Normal University,Changsha 410081,China;Hunan Key Laboratory of Geospatial Big Data Mining and Application,Changsha 410081,China)

机构地区：[1]湖南师范大学地理科学学院,长沙410081 [2]地理空间大数据挖掘与应用湖南省重点实验室,长沙410081

出　　处：《矿物岩石地球化学通报》2022年第1期156-165,共10页Bulletin of Mineralogy, Petrology and Geochemistry

基　　金：有色金属成矿预测与地质环境监测教育部重点实验室开放基金项目(2019YSJS07);国家重点研发计划项目(2019YFC1805901);湖南省教育厅科学研究项目(19C1178)。

摘　　要：位于祁漫塔格成矿带上的虎头崖矿床是典型的多金属矿床。本文运用原位微区硫、铅同位素分析方法,对该矿床Ⅱ号脉、Ⅵ号脉不同硫化物的硫同位素组成和Ⅶ号脉方铅矿铅同位素组成数进行了分析,探讨其成矿物质来源并分析矿床类型。结果表明,Ⅱ号脉、Ⅵ号脉黄铜矿、黄铁矿的δ^(34)S值为+5‰~+6.76‰,平均6‰,反映成矿物质主要来源于地幔岩浆,并受围岩影响,两矿脉硫同位素均值的差异,可能与围岩中硫的不同及参与成矿的程度有关;Ⅶ号脉方铅矿铅同位素组成总体变化较小(^(208)Pb/^(204)Pb、^(207)Pb/^(204)Pb、^(206)Pb/^(204)Pb的值分别为38.410~38.504、16.627~15.656、18.552~18.583),铅同位素增长曲线图显示铅同位素散点主要分布于造山带和上地壳铅演化线范围内,反映Ⅶ号脉成矿物质主要来源于地壳。通过硫同位素的变化范围并结合前人研究认为虎头崖矿床为矽卡岩型矿床。The Hutouya copper-lead-zinc polymetallic deposit in Qinghai Province is a typical representative of polymetal-lic deposits in the Qimantag metallogenic belt.In this paper,by using the in-situ micro analysis methods of sulfur and lead isotopes,we have analyzed sulfur isotope compositions of sulfides in the No.2 and No.6 veins and the lead isotope compositions of galena samples in the No.7 vein of the deposit,and have discussed the source of ore-forming materials and the type of the deposit.The results show that theδ^(34)S values of sulfides such as chalcopyrite and pyrite in the No.2 and No.6 veins of the deposit vary from+5‰to+6.76‰,with an average of 6‰,reflecting that sulfur was mainly derived from deep-sourced magma,with little influence of sulfur from the wallrocks.It is inferred that the difference of mean sulfur isotope values of sulfides in different ore veins may be related to the different sources and mixing degrees of sulfurs from different wallrocks.The overall change of lead isotope compositions of galena samples in the No.7 vein is small(^(208)Pb/^(204)Pb,^(207)Pb/^(204)Pb,^(206)Pb/^(204)Pb values are 38.410-38.504,16.627-15.656,18.552-18.583,respectively).Those lead isotopic values are mainly plotted around the lead evolution lines of the orogenic belt and the upper crust,re-flecting that the ore-forming materials of the No.7 vein were mainly sourced from the crust.Combined with the sulfur iso-topes and previous studies,it is believed that the Hutouya deposit belongs to a skarn deposit.

关 键 词：原位硫、铅同位素 成矿物质来源 虎头崖矿床 

分 类 号：P597[天文地球—地球化学]