Study on the fluid inclusion from Dongxiang copper deposit,Jiangxi Province,China
CAI YiTao1,NI Pei1,SHEN Kun2,ZHU XiaoTing1,3,HUANG SuJin4,ZHANG XiuChang4 and XU Jihui51. State Key Laboratory for Mineral Deposits Research,Institute of Geo-Fluids,School of Earth Sciences and Engineering,Nanjing University,Nanjing 210093,China2. Shandong Institute and Laboratory of Geological Science,Jinan 250013,China3. Nanjing Institute of Geology and Mineral Resources,Nanjing 210093,China4. Dongtong Mining Ltd.,Jiangxi Copper Corporation,Dongxiang 331812,China5. Geological Prospecting Engineering Co.,Ltd. of Jiangxi Copper Industry Group Corporation,Dexing 334224,China
According to the study on the metallogenic fluid characteristic from Dongxiang copper deposit,we examine the metallogenic mechanism,the nature and origin of ore-forming fluid.Based on petrographic observations of ore-bearing quartz collected from the deposit,we have found that there are three different generations of quartz.Fluid inclusion studies show that the homogenization temperature and primary salinities are 144~195℃ and 0.35%~4.95% NaCleqv in the first generation,respectively.The second generation formed in relatively higher temperature range 193~298℃,and salinities are 1.40%~6.59% NaCleqv.The thrid generation of quartz mainly consists of pyrite,chalcopyrite and quartz,the primary inclusions are generally three types:vapor(type II),brine(type I),and daughter-mineral bearing multiphase inclusions(type V)in the third generation.The statistics on the measured filling temperatures of type II and type V reveal peaks at 300~340℃ and 280~320℃ respectively,while those on the salinities of fluid inclusions peak at 0.35%~5.86% NaCleqv and 29.4%~41.9% NaCleqv respectively.Raman analysis of the fluid inclusions indicates that,in the gaseous phase,water vapor is dominant with small amount of CO2 and CH4.Hydrogen and Oxygen isotopic compositions are within the range of magmatic water.Fluid boiling resulted in the discharge of a large amount of copper from Cu-bearing fluid.