地质学报2017，Vol.91Issue(7)：1542-1564,23.
西藏多龙矿集区地堡铜(金)矿床年代学、流体包裹体、地球化学特征及其成因类型研究
Geochronology, Fluid Inclusions, Geochemical Characteristics of Dibao Cu (Au) Deposit, Duolong Ore Concentration Area,Xizang (Tibet), and Its Genetic Type
摘要
Abstract
Duolong ore cluster area,located in the southern Qiangtang terrane,northern Bangong Lake-Nujiang metallogenic belt,is the largest porphyry-epithermal copper (gold) ore cluster area discovered in recent years.Dibao is located in the most southwest edge of the Duolong ore cluster area.Despite its good exploring prospect,research work is still weak.To promote resource exploration and provide theoretical basis for metallogenic regularity,we conducted zircon U-Pb dating,fluid inclusions and geochemistry research.The 206Pb/238U weighted average age of 111.2±0.4 Ma (MSWD=0.67) obtained for ore-bearing porphyry is consistent with the mineralization magmatism time limit of the Duolong ore cluster area.The fluid inclusion analysis of quartz vein indicates that ore-forming fluid temperatures of the main metallogenic period range from 140℃ to 382℃,with most focusing around 240℃ to 280℃.In the diagenetic stage,salinity of I-type inclusions from quartz phenocryst ranges from 0.2 ％ NaCleqv.to 20.7 ％ NaCleqv.and mineral-bearing inclusions from 33.6％NaCleqv.To 43.9％NaCleqv.In the metallogenic stage,salinity of I-type inclusions from gypsum-free quartz veins is 0.2％NaCleqv.to 20.8％NaCleqv.and salinity of I-type inclusions from pyrite quartz veins is 1.1％NaCleqv.to 11.1％NaCleqv..Salinity of I-type inclusions from gypsum is 0.5％ NaCleqv.to 9.3％ NaCleqv..Analysis of main elements and trace elements of drilling DNZK6428 samples and factor analysis results indicate that F1,F2 and F3 represent diagenetic stage and factor principal components are Y-Ho-Er-Tm-Yb-Dy-Lu-Tb-Eu-Gd-Sm-La-Ce-Pr-Nd-SiO2-Al2O3-CaO,F4 and F5 stands for copper (gold) mineralization stage,and factor principal components are Sn-Sb-Ba-Fe2O3-Sr-| SiO2 |-Ni-Cu-U-In-Cd-Au-Zn.Pyrite has a centralized δ34 SV-CDT range of-7.8‰ to 4.1‰ with an average of-4.23‰,indicating sulfur mainly derived from deep magmatic sulfur,close to mantle sulfur.Granular pyrite has Co/Ni ratios of 0.207 to 10.775 with an average of 4.39,and vein pyrite has Co/Ni ratios of 0.353 to 23.155 with an average of 3.802,indicating that two types of pyrite was hydrothermal genesis.Mineragraphy and petrography study shows a typical mineral assemblage of alunite and enargite,suggesting that the Dibao Cu (Au) deposit belongs to high-sulfidation epithermal deposit.关键词
锆石U-Pb测年/含矿斑岩/硫同位素/流体包裹体/高硫型浅成低温热液矿床Key words
zircon U-Pb dating/ore-bearing porphyry/sulfur isotope/fluid inclusions/high sulfidation epithermal deposit引用本文复制引用
乔东海,赵元艺,汪傲,李玉彬,郭硕,李小赛,王松..西藏多龙矿集区地堡铜(金)矿床年代学、流体包裹体、地球化学特征及其成因类型研究[J].地质学报,2017,91(7):1542-1564,23.基金项目
本文为中国地质调查局地质调查项目“西藏多龙矿床技术经济与环境综合评价”(编号DD20160330)和国家重点基础研究发展计划“973”项目(编号2011CB403103)之课题三“青藏高原南部增生造山成矿系统发育机制”联合资助成果. （编号DD20160330）
