吉林省新华龙钼矿床流体包裹体

Fluid Inclusions in the Xinhualong Molybdenum Deposit,Jilin Province

新华龙钼矿床位于中国东北地区吉林省东部,是一个新发现的斑岩型钼矿床。矿床产于花岗闪长斑岩中。矿床成矿阶段包括石英-浸染状辉钼矿、石英-网脉状辉钼矿、石英-黄铁矿-黄铜矿、石英-多金属硫化物和石英-碳酸盐化5个阶段。流体包裹体实验结果表明:流体包裹体的类型主要为气液两相包裹体,其次为纯气相和纯液相包裹体,还有少量含子矿物的多相包裹体。流体包裹体的均一温度为172~385℃,盐度(w(NaCl))为8.51%~45.44%。从早阶段到晚阶段成矿流体温度具有规律的演化,均一温度分别为360~390℃、270~350℃、250~260℃、220~230℃、170~190℃。其中:含子矿物多相包裹体均一温度为272~385℃,盐度为35.79%~45.44%,密度为1.07~1.08g/cm3;气液两相包裹体均一温度为172~381℃,盐度为8.51%~23.36%,密度为0.70~0.99g/cm3。激光拉曼光谱分析表明,包裹体的气体成分主要为CO2、H2O、N2和CH4。包裹体岩相学及测温表明,流体由早期的高温、高盐度、含二氧化碳的含矿流体在主成矿阶段发生流体包裹体的沸腾、CO2逸出、温度降低等过程,导致大量金属硫化物沉淀。结合氢氧同位素特征,初步确定该矿床的成矿流体主要以岩浆水为主,后期有大气水的加入。流体沸腾是新华龙钼矿床成矿的重要机制。

The Xinhualong molybdenum deposit, discovered porphyry deposit. The orebodies are located in the eastern Jilin Province, is a newly mainly hosted in granodiorite-porphyry. The hydrothermal ore-forming processes can he divided into five stages= quart^disseminated molybdenite, quartz-stockwork molybdenite, quartz-pyrite-chalcopyrite, quartz-polymetallic sulfides, quartz- carbonate. Some conclusions have been drawn through petrographic observation of fluid inclusions in this deposit= there are mainly gas liquid two phase （Lq-V） inclusions, subordinately pure gas （V） and pure liquid inclusions （L）, and minor daughter minerals bearing multiphase inclusions （L＋V＋S）. The homogenization temperatures of fluid inclusions regularly change from the early stage to the late stage.The homogenization temperatures and salinities of fluid inclusions ranges from 172 - 385 ℃, and from 8.51%-45. 44%, respectively. The peak values of homogenization temperatures of fluid inclusions formed in different stages are separately 360 - 390 ℃, 270 - 350 ℃, 250 - 260 ℃, 220 - 230 ℃, 170 - 190 ℃. The homogenization temperatures of daughter minerals bearing inclusions mainly range from 272 -385 ℃, salinities from 35. 79%- 45.44%, and densities from 1.07 - 1.08 g/cm3 respectively. Gas liquid two-phase inclusions are mainly in ranges of 172 -381 ℃, 8.51 %-23.36%, and 0.7 -0.99 g/cm3 respectively. Laser Raman spectroscopy of inclusions indicate that the gas components are CO2, H20, N2 and CH4. Petrographic and microthermometric studies indicate that the ore-forming fluid of the first and the second stage, with high temperature, high salinities, CO2-bearing, took place boiling. The fluid boiling resulted in CO2 escaping, temperature decreasing and abundant metal sulfides precipitating. Moreover, data of oxygen and hydrogen isotope indicate that the ore-forming hydrothermal fluid was dominated by magmatic water with mixing of meteoric water in the later stage, and the mechanism for ore-metals precipitation is fluid-boiling.