西藏波龙斑岩铜金矿床成矿流体物理化学条件

应用英国Linkam THNSG600型冷热台测试和前人的经验公式，对西藏波龙斑岩铜金矿床在岩浆晚期、磁铁矿-辉钼矿阶段、黄铜矿-黄铁矿阶段和硬石膏-黄铁矿阶段等4个成矿阶段利于主成矿元素Cu迁移的流体包裹体的一般特征及物理化学条件进行研究。研究结果表明，该矿床流体包裹体类型以含石盐和硫化物子矿物的三相包裹体为主，为高温（232~549 ℃）、低压（1.40×105~234.41×105 Pa）、高盐度（NaCl质量分数28.65%~52.16%）、中—高密度（1.0683~1.1598 g/cm3）的流体；随着成矿进程的发展，各阶段流体逸度和活度均逐渐降低，pH值和Eh值逐渐升高，铜主要以Cu（H₂S）（HS）₂-形式存在，说明Cu在高温酸性流体中易成矿。 

STUDY ON THE FLUID INCLUSION PHYSICOCHEMICAL CONDITIONS OF BOLONG PORPHYRY COPPER-GOLD DEPOSIT IN TIBET

Using Linkam THNSG600 dating and calculating by experience formulas, this paper discusses the fluid inclusion characteristics of Bolong porthyry copper-gold deposit in Tibet, which is beneficial to the migration of the main ore-forming element Cu, and the metallogenic process includes four periods: magma-advanced stage, magnetite-molybdenite period, chalcopyrite-pyrite period and anhydrite-pyrite period. It shows that the type of fluid inclusion is mainly the three-phases inclusion including NaCl and metal sulfide daughter minerals. The ore-forming fluid forms in high temperature (232~549 ℃) and low pressure (1.40×105~234.41×105 Pa), with high salinity (28.65~52.16wt% NaCl) and middle-high density (1.0683~1.1598 g/cm3). Along with the metallogenic process, the fluid fugacity and activity gradually reduce in each stages, while the values of pH and Eh increase. The element Cu mainly exits in the form of Cu(H₂S)(HS)₂-, which shows that Cu is easier to mineralization in high tempreture and acidic fluids.