地质学报2017，Vol.91Issue(6)：1259-1268,10.
青海玉树多彩地玛铅锌矿C-O、S同位素组成及成矿物质来源分析
C-O and S Isotopic Compositions of the Duocaidima Pb-Zn Deposits in the Yushu Area, Qinghai Province and Their Metallogenic Materials Sources Analysis
摘要
Abstract
Duocaidima lead-zinc ore deposit,located at the Yushu area of Qinghai,is tectonically situated in the northeastern margin of Tibetan Plateau.Bounded between the Xijir Ulan-Jinshajiang suture zone and Bangonghu-Nujiang suture zone,the deposit belongs to the Cu-Pb-Zn-Ag polymetallic mineralization belt in the northern part of the Sanjiang area.Combining with regional geological survey and research status,we carried out C-O isotope analysis of carbonatic rock in wall rocks and two-stage hydrothermal calcite veins,and S isotope analysis of sulfide minerals and barite.The results are given as follows.The δ13C and δ18O value ranges of calcites in wall rocks are-1.6‰～+3.0‰ and +21.2‰～+27.6‰ respectively,suggesting that calcites belong to normal marine carbonate deposition,with C and O deriving from seawater.The δ13C and δ18 O values of calcite veins are-1.5‰ ～ + 2.1‰ and + 15.2‰ ～ + 20.3‰ respectively,while the C derived from the dissolution of carbonate rocks,and the 18O depleted during isotopic exchange of water-rock reaction.The δ34S values of barite range from +12.3‰ to +15.7‰ and δ34S values of galena,sphalerite and pyrite all range from-8.2‰ to +5.7‰ with a peak of-2.0‰～ -3.0‰,which reflects a feature of rich light sulfur,and sulfur was derived from extraction of the thermal brine in basin,thermal decomposition and reduction of the organic matters and fractionation of low-valence sulfur.A relative wide range of δ34S reflects the interaction of ore-forming material with wall rocks during the flowing of hydrothermal fluids in the basin.Sedimentary and biogenetic sulfur in organic matter-rich strata in the basin may provide partial sulfur source for the mineralization.关键词
多彩地玛/铅锌矿/C-O同位素/S同位素/碳酸盐岩Key words
Duocaidima area/Pb-Zn deposit/C-O isotope/S isotope/carbonate rocks引用本文复制引用
赵利,陈根,董彦龙,尹行..青海玉树多彩地玛铅锌矿C-O、S同位素组成及成矿物质来源分析[J].地质学报,2017,91(6):1259-1268,10.基金项目
本文为青海省地勘基金项目(青国土资勘[2012]87)和四川省科技厅国际合作计划项目(2015HH0071)资助的成果. （青国土资勘[2012]87）
