投稿时间：2012-07-06
修订日期：2012-12-24
中文摘要:加当根矿床是近几年新发现的研究程度较低的斑岩型铜矿床,文章对含矿斑岩、石英脉和绢英中的石英岩开展了详细的流体包裹体特征及氢、氧同位素组成研究。该矿床流体包裹体类型丰富,以大量发育含子晶多相包裹体为特征,子矿物种类多样,包括石盐、钾盐、石膏、黄铜矿、黄铁矿、赤铁矿等。石膏、赤铁矿的出现,暗示着岩浆结晶早期处于氧化环境。成矿流体由来自岩浆的高温、高盐度流体和以天水成因为主的中-高温、低盐度流体2个端员组分组成,高温、高盐度流体为主要载矿流体,形成温度>440℃,w(NaCleq)为30%~82%,其是在浅成条件下于岩浆结晶的最后阶段从浅部岩浆中直接出溶形成的;中-高温、低盐度流体主要来源于天水或天水与晚期岩浆热液的混合,温度主要集中在220~360℃,w(NaCleq)<20%。石英流体包裹体氢、氧同位素研究表明流体混合在卸载成矿上的重要性,石英脉和绢英岩化阶段是含矿物质沉淀的主要阶段。脉石英的流体温度集中在280~440℃,绢英岩化蚀变石英中流体包裹体的均一温度介于240~340℃。
Abstract:The Jiadanggen porphyry copper deposit was discovered in recent years, but its research is very insufficient. This paper mainly deals with the homogenization temperature of fluid inclusions and the evolution tendency of ore-forming fluid. The fluid inclusions in the pluton and quartz veins are characterized by abundantly daughter minerals-bearing inclusions in which daughter minerals composed of halite, sylvite, gypsum, chalcopyrite, pyrite and hematite. The presence of gypsum and hematite imply oxidation environment at the early stage of magmatic crystallization. The microthermometric analysis of inclusions reveals that the metallogenic fluid consists of both high-temperature, hypersaline fluids and medium-low temperature, low salinity ones. High temperature, hypersaline fluids with temperature of over 440℃, salinity of 30%~82%, and average salinity of 47.3%~67.5% directly resulted from the fluid exsolution from a shallow crystallizing melt at the final stage. The medium-low temperature and low salinity fluid with temperature concentrated in 220~360℃ and salinity lower than 20% was mainly derived from meteoric water, probably mixed with later-stage magmatic hydrothermal fluids. This paper explains the importance of fluid mixing in the ore-forming and unloading process on the basis of the hydrogen and oxygen isotopic composition. The temperature of veined quartz is between 280℃ and 440℃, and the temperature of beresitization is between 240℃ and 340℃, which are the main temperature intervals of mineral precipitation.
keywords:geochemistry porphyry copper deposit fluid inclusions geochemistry fluid mixing Jiadanggen East Kunlun
文章编号：
中图分类号：P618.41
文献标志码：
基金项目:本文得到中国地质调查局地质调查项目(编号: 1212011085528, 1212011121089)和中国地质调查局青年地质英才计划(201112)的联合资助
引用文本：
于淼,丰成友,肖晔,刘建楠,李大新,李国臣,马圣钞.2013.青海共和县加当根斑岩铜矿床成矿流体特征及演化[J].矿床地质,32(1):133~147YU Miao,FENG ChengYou,XIAO Ye,LIU JianNan,LI DaXin,LI GuoChen,MA ShengChao.2013.Features and evolution of metallogenic fluid in Jiadanggen porphyry copper deposit of Gonghe Country, Qinghai Province[J].Mineral Deposits32(1):133~147
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