新疆康西瓦铅银矿床成矿时代及矿床类型研究  

Metallogenic Age and Deposit Type of the Kangxiwa Pb-Ag Deposit in Xinjiang,China

作　　者：陈谋 王核[1] 张晓宇 闫庆贺 高昊 CHEN Mou;WANG He;ZHANG Xiaoyu;YAN Qinghe;GAO Hao(Key Laboratory of Mineralogy and Metallogeny,Guangzhou Institute of Geochemisty,Chinese Academy of Sciences,Guangzhou 510640,Guangdong,China;University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院广州地球化学研究所矿物学与成矿学重点实验室,广东广州510640 [2]中国科学院大学,北京100049

出　　处：《大地构造与成矿学》2024年第5期1017-1029,共13页Geotectonica et Metallogenia

基　　金：新疆维吾尔自治区科技重大专项(2019B00011);新疆维吾尔自治区重大科技专项(2020A03005);国家自然科学基金项目(91962215,41972088);第二次青藏科考项目(2019QZKK0802)联合资助。

摘　　要：康西瓦铅银矿床位于西昆仑大红柳滩岩体西缘,该矿床主要有四个矿体,矿体呈层状产出,赋存于蚀变大理岩中。野外和显微观察显示,康西瓦铅银矿床主成矿期由早到晚分为三个阶段:(1)黄铁矿-毒砂阶段,(2)方铅矿-黄铁矿-毒砂阶段,(3)碳酸盐阶段。本文以康西瓦铅银矿床主成矿阶段(2)中的方铅矿、黄铁矿、毒砂以及石英为研究对象,分别对方铅矿进行Rb-Sr同位素年代学分析、方铅矿和黄铁矿进行原位S同位素分析、毒砂进行EMPA主量元素分析、石英进行H-O同位素分析。研究获得方铅矿Rb-Sr等时线年龄为207.0±3.6Ma;黄铁矿的δ^(34)S值为-29.7‰~-2.7‰,方铅矿的δ^(34)S值为-11.6‰~-6.1‰,表明成矿物质中硫的来源具有岩浆与地层混合特征;毒砂中的As含量原子百分数在28.17%~32.26%,估算成矿温度为290℃;石英中的δD_(H_(2)O)值为-78.7‰~-69.2‰,δO_(H_(2)O)值为8‰~11.7‰,显示出岩浆水与变质水的混合特征。本次研究认为,康西瓦铅银矿床形成于晚三叠世末,是与岩浆活动有关的中温热液型铅银矿床。The Kangxiwa Pb-Ag deposit is located on the western margin of the Dahongliutan pluton in West Kunlun.The deposit consists of four stratiform orebodies in altered marbles.Field and microscopic observations showed that the main metallogenic stage of the Kangxiwa Pb-Ag deposit can be divided into three substages,from early to late:①pyrite-arsenopyrite,②galena-pyrite-arsenopyrite,and③carbonate substages.Taking galena,pyrite,arsenopyrite,and quartz in the substage②of the Kangxiwa Pb-Ag deposit as the research object,Rb-Sr isotopic chronological analysis of galena,in-situ S isotopic analyses of galena and pyrite,EMPA analysis of arsenopyrite,and H-O isotopic analyses of quartz were carried out for the first time.The galena Rb-Sr isochron age of 207.0±3.6 Ma,theδ^(34)S values of−29.7‰to−2.7‰for pyrite and−11.6‰to−6.1‰for galena indicate that the source of S has characteristics of magma and strata mixing.The As atomic percentage of arsenopyrite ranges from 28.17%to 32.26%.The metallogenic temperature was estimated to be 290℃.δD_(H_(2)O)value of quartz(−78.7‰to−69.2‰)andδO_(H_(2)O)value of water(8‰to 11.7‰)demonstrate the mixing characteristics of magmatic and metamorphic water.The results show that the Kangxiwa Pb-Ag deposit is a mesothermal hydrothermal Pb-Ag deposit related to magmatism at the end of Late Triassic.

关 键 词：RB-SR年龄 原位S同位素 EMPA H-O同位素 康西瓦铅银矿 西昆仑 新疆 

分 类 号：P618[天文地球—矿床学]