矿床地质2018，Vol.37Issue(1)：37-49,13.DOI:10.16111/j.0258-7106.2018.01.003
西藏措勤县德能铜多金属矿床成矿物质来源的矿物学和S-Pb同位素证据
Ore-forming materials of Deneng copper polymetallic deposit, Coqen County, Tibet: Evidence from mineralogy, and S and Pb isotopes
摘要
Abstract
In order to investigate the source of ore-forming materials of the Deneng copper polymetallic deposit,the authors analyzed pyrite,galena,chalcopyrite and chlorites by electron microprobe analysis and also investigated Pb,S isotope compositions of galena,sphalerite and pyrite.The results of electron microprobe analysis shows that the sulfur content in the sulfides of the Deneng copper polymetallic deposit is lower than the theoretical value.S/Fe ratios of pyrite are from 1.067 to 1.094 (1.083 on average),Co/Ni ratios are more than 1,and cubic crystal{100 } pyrite is developed.According to the study,the authors have drawn the conclusion that the sulfide crystallized under the conditions of high temperature and high oxygen fugacity.Chemical analysis of chlorite shows the mineral is rich in Fe and belongs to prochlorite.Calculation yielded the formation temperatures of chlorite in the range of 185℃and266℃,with an average of 221℃.This indicates that ore-forming fluids might have evolved to low sulfur fugacity under middle-low temperature,acidic and reduction condition after the metallogenic period.The sphalerite,galena and pyrite have stable Pb isotopic compositions:208Pb/204Pb ratios from 38.937 to 39.217,207Pb/204Pb ratios from 15.640 to 15.718 of and 206Pb/204Pb ratios from 18.521 to 18.601.Theμ values of sulfides are between 9.53 and 9.68 and the ω values are from 38.29 to 39.76.The authors thus infer that the source of Pb might have been mainly derived from the metamorphic rocks of Nyainqentanglha Group.The δ34S values of sulfides vary in the range of + 6.6‰～ + 9.3‰,indicating that the source of S was probably derived from granitic magma.关键词
地球化学/S-Pb同位素/矿物学/成矿物质/德能铜多金属矿床/措勤/西藏Key words
geochemistry/sulfur and lead isotopes/mineralogy/ore-forming material/Deneng copper polymetallic deposit/Coqen/Tibet分类
天文与地球科学引用本文复制引用
于玉帅,杨竹森,田世洪,周云,高原..西藏措勤县德能铜多金属矿床成矿物质来源的矿物学和S-Pb同位素证据[J].矿床地质,2018,37(1):37-49,13.基金项目
本文得到国家自然科学基金项目“西藏尼雄矽卡岩铁矿成矿流体演化与成矿作用机制”(编号:41503040)和国家重点研发计划“青藏高原大陆碰撞铅锌成矿系统深部结构与成矿过程”课题(编号:2016YFC0600306)联合资助 （编号:41503040）
