地质学报2017，Vol.91Issue(5)：1066-1082,17.
新疆维宝矽卡岩铜铅锌矿床维西矿段矿物学特征
Mineralogical Characteristics of the Weixi Ore Block in the Weibao Skarn-type Copper-Lead-Zinc Deposit, Xinjiang
摘要
Abstract
The Weibao skarn-type Cu-Zn-Pb polymetallic deposit,located at the junction of Xinjiang and Qinghai,tectonically belongs to the eastern part of the Qimantagh orogen.It comprises three ore blocks,referred to as Weidong,Main and Weixi respectively.The Weidong block is characterized by abundant Pb-Zn mineralization and minor Cu mineralization,while the Weixi block is characterized by abundant Cu-Pb-Zn mineralization.In this study,we carried out detailed research on the mineralogy of the skarn and ore samples from the Weixi block.On the basis of the mineral assemblages,ore structures and crosscutting relationship,the ore-forming process of the Weibao deposit can be preliminarily divided into four stages,i.e.,the early skarn stage,the late skarn stage,the quartz-sulfide stage and the quartz-carbonate stage,with the quartz-sulfide stage being the main ore-forming stage.Skarn minerals are mainly composed of garnet,pyroxene,epidote and amphibole,whereas sulfides mainly contain chalcopyrite,galena,sphalerite,pyrite and pyrrhotite.Electron microprobe analyses indicate that the garnet is compositionally predominated by andradite molecules (And=59.00％～97.70％) and grossular molecules (Gro=1.92％～40.42％),therefore belonging to the andradite-grossular series;pyroxene is predominated by diopside molecules (Di =45％ ～ 91％) and hedenbergite molecules (Hd =8％ ～ 53％),therefore manifesting as diopside and minor hedenbergite;amphibole belongs to the tremolite-actinolite series,although its composition varies greatly.Mineral assemblages and chemical compositions suggest that the skarn in the Weixi block is typical of calcic skarn.Moreover,the chemical components of garnet with zoning vary in a regular way that Al2Oa contents increase and then decrease while FeOTdecreases and then increases.The process shows metasomatism occurred along with change of pH in the ore-forming fluid continuously from weak acidic-alkaline to neutral condition and ultimately to weak acidic-alkaline condition.High values of metals to sulfur in the sulfide of the Weixi block are higher than theoretical values,indicating that they likely formed in a high sulfur fugacity environment.In addition,sphalerite is characterized by the variable Fe and Zn contents (Zn=54.50％～64.75％,Fe=1.15％～10.16％),which might result from the fluctuation of ore-forming temperatures and sulfur fugacities.关键词
钙矽卡岩/电子探针/维宝矿床/新疆/祁漫塔格Key words
calcic skarn/Electron microprobe/Weibao deposit/Xinjiang/Qimantagh引用本文复制引用
钟世华,丰成友,李大新,赵一鸣,任雅琼,周建厚,刘建楠,王辉,于淼..新疆维宝矽卡岩铜铅锌矿床维西矿段矿物学特征[J].地质学报,2017,91(5):1066-1082,17.基金项目
本文为国土资源部公益性行业科研专项经费项目(编号201411025)、中国地质调查局地质调查项目(编号1212011085528、12120113093600)、中国地质调查局高层次地质人才培养计划(编号201309)和青年地质英才计划(编号201112)资助的成果. （编号201411025）
