大兴安岭中南段布敦化铜矿床H-O-S-Pb同位素特征及成矿指示  

H-O-S-Pb isotopic components of the Budunhua Cu deposit in the middlesouth part of the Da Hinggan Mountains and their implications for the oreforming process

作　　者：武新丽[1] 毛景文[1,2] 周振华[2] 欧阳荷根[1] 

机构地区：[1]中国地质大学地质过程与矿产资源国家重点实验室,地球料学与资源学院,北京100083 [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：《中国地质》2012年第6期1812-1829,共18页Geology in China

基　　金：中国地质调查局地质大调查项目(1212011085260);内蒙古重要矿产资源潜力评价及区域成矿规律研究项目(2006-02-YS01)联合资助

摘　　要：布敦化铜矿是大兴安岭中南段一个斑岩-热液脉型复合铜矿床,包括南部的金鸡岭斑岩型铜矿段和北部的孔雀山热液脉型铜矿段。本文在详细的矿床地质特征研究基础上,通过对矿体的氢、氧、硫和铅同位素系统研究,探讨了成矿流体和成矿物质来源以及成矿机制。氢、氧同位素组成表明,金鸡岭矿段与孔雀山矿段早期成矿流体主要以岩浆水为主,至成矿晚期有大气降水的参与。硫同位素分析结果表明金鸡岭矿段相对富集重硫,成矿热液的硫同位素组成为+2.54‰-+2.60‰。而孔雀山矿段相对富集轻硫,成矿热液的S同位素组成为-1.84‰--1.71‰,两矿段的硫同位素组成表明硫主要来源于地球深部,铅同位素组成则表明铅具壳幔混合的特点,其来源与岩浆活动密切相关。结合大兴安岭中南段区域地质演化历史认为,布敦化矿床两个矿段的成矿作用均是由流体混合而导致黄铜矿等金属硫化物的大量沉淀。The Budunhua Cu deposit is a porphyry-hydrothermal vein type composite deposit in the middle-south part of the Da Hinggan Mountains.The deposit consists of the southern Jinjiling porphyry Cu ore block and northern Kongqueshan hydrothermal vein-type Cu ore block.Based on a detailed analysis of geological characteristics and a study of hydrogen,oxygen,sulfur,and lead isotopes in hydrothermal minerals,this paper has discussed the origin of ore-forming fluid and materials and genesis of the Budunhua deposit.Hydrogen and oxygen isotope analyses indicate that the ore-forming fluid in the early ore-forming stage in Jinjiling and Kongqueshan ore blocks was mainly magmatic water,whereas that in the late ore-formaing stage was probably a mixed fluid of magmatic and meteoric water.Sulfur isotope analyses show that the Jinjiling ore block is relatively rich in 34S,with sulfur isotope composition of ore-forming fluid being ＋2.54-＋2.60‰,while the Kongqueshan ore block is relatively depleted in 34S,with sulfur isotope composition of ore-forming fluid being-1.84--1.71‰.The sulfur isotope composition of the two ore blocks suggest a deep-seated source,and the lead isotope results display crust-mantle mixing characteristics closely related to magmatism.With the regional geological evolution history of the middle-south part of the Da Hinggan Mountains as a premise,the mineralization of the Jinjiling and the Kongqueshan Cu ore blocks in the Budunhua Cu deposit should be mainly related to fluid mixing which led to the precipitation of metal sulfides.

关 键 词：稳定同位素 成矿流体 成矿物质 布敦化铜矿 大兴安岭中南段 

分 类 号：P618.41[天文地球—矿床学]