云南元江岔河铜矿床流体包裹体特征及其意义

摘要

To research the meta11ogenic f1uid characteristics of chahe copper deposit Yuanjiang, Yunnan,according to the study of petrographic characteristics of the f1uid inc1usions,we find that the f1uid inc1usions of chahe copper deposit be1ong to gas - 1iquid two - phase inc1usion. The inc1usion microscopic temperature measurement data of quart formed during minera1ization indicate that the homogenization temperature is between 195. 8 ~212 ℃however,it is main1y concentrated between in 140~190 ℃( average 176 ℃),and the sa1inity is between 10. 62% ~19. 62%,these indicate that the ore - forming f1uid is main1y characteristic with medium - 1ow temperature, moderate sa1inity, 1ow density. Composition of quart group inc1usions show that,N2 is dominate in vapour phase,CO2 ,H2 O, O2 is second. This feature is different from any sing1e component of inc1usion, which imp1y that the meta11ogenic f1uid is a mixture. Combine with the geo1ogic features,we suggest that the metamorphic water is the main meta11ogenic f1uid. The f1uid phase in inc1usion main1y consist of SO4 2 ,C1-is next, the va1ue of F-/C1- is much 1ow, this indicate that the meta11ogenic f1uid is simi1ar to atmospheric meteoric water,Na+/K+ is about 1 which suggest the meta11ogenic f1uid maybe contain magmatic water. As a consequence,combined with the character of minera1 geo1ogy we conc1ude that the meta11ogenic f1uid of Chahe copper deposit is a mixture f1uid which probab1y contain metamorphic water,magmatic water,atmospheric meteoric water.%为研究云南元江岔河铜矿床成矿流体特征，通过对流体包裹体的岩相学特征研究发现，岔河铜矿床流体包裹体分以气液两相包裹体为主。包裹体显微测温数据表明，成矿期石英流体包裹体均一温度在94~371℃之间，平均值为176℃，盐度（ NaC1的质量分数）介于10.62%~19.62%之间，说明成矿流体主要以中-低温、中等盐度为特征。从石英群体包裹体成分分析结果发现，包裹体气相成分主要以N2为主，CO2、H2 O、O2次之的特点，与任何单一流体成分均不相似，说明成矿流体可能为一种混合流体；结合地质特征，认为变质水应为主要成矿流体，液相成分以SO2-4为主，C1-次之，F-与C1-比值很低，说明成矿流体具有大气降水特征；Na+/K+值在1附近波动，说明成矿流体可能有岩浆水参与。因此，结合矿床地质特征，认为岔河铜矿床成矿流体为一种混合流体，可能为变质水、岩浆水和大气降水共同作用。