黑龙江鹿鸣钼矿床成矿流体及演化  

Ore-forming fluid and evolution of Luming molybdenum deposit,Heilongjiang Province

作　　者：王琳琳[1] 孙丰月[1] 徐九华[2] 王可勇[1] 王力[1] 许庆林[3] 

机构地区：[1]吉林大学地球科学学院,长春130061 [2]北京科技大学资源工程系,北京100083 [3]山东科技大学地球科学与工程学院,青岛266590

出　　处：《岩石学报》2015年第4期979-990,共12页Acta Petrologica Sinica

基　　金：中国地质调查局项目(1201185485)资助

摘　　要：黑龙江鹿鸣钼矿床位于小兴安岭-张广才岭多金属成矿带内,赋存于二长花岗岩体内。根据矿石组构、蚀变类型和脉体穿插关系,将鹿鸣钼矿床自早到晚划分为3个成矿阶段：1）钾硅化浸染状矿化阶段;2）硅化网脉状矿化阶段;3）绿泥石-碳酸盐化阶段。鹿鸣钼矿床包裹体类型复杂,盐水溶液包裹体、富气相包裹体、含CH4（CO2）包裹体和含子晶多相包裹体共存,其中盐水溶液包裹体均一温度集中于133-425℃,盐度为1.6%-16.1%NaCleqv。富气相包裹体均一温度集中在243-500℃,盐度为1.2%-14.1%NaCleqv。含子晶多相包裹体最终均一温度为297-449℃,盐度为38.2%-53.1%NaCleqv。含CH4（CO2）包裹体经激光拉曼光谱分析证实其中以CH4为主,少数含微量的CO2,均一温度为334-437℃。硫同位素测试结果显示：δ34S变化范围在4.5‰-5.7‰,成矿流体中的硫主要来源于岩浆热液。氢、氧同位素分析数据投到δD-δ^18OH2O图解中,投影点落在岩浆水附近并向大气降水飘移,可以推断主成矿期的成矿介质水为岩浆水并混有少量的大气降水。鹿鸣钼矿床主成矿期压力估算为30-90MPa,推测成矿深度为3-9km。成矿流体演化过程可能为岩浆房最先分离出一个单一相的高温、中等盐度的H2O-NaCl-CH4（CO2）超临界流体,后由于减压和不同流体的混入导致流体沸腾发生不混溶并捕获形成多种类型包裹体。随着成矿流体不断演化,成矿温度逐步降低,金属矿物也不断沉淀成矿。通过对鹿鸣钼矿床中流体包裹体的研究可知,与成矿有关的流体不是单一的岩浆分异的结果,也有大规模其他流体的混入,矿区复杂的地质构造环境也为钼成矿提供了条件。The Luming molybdenum deposit,located in the Lesser Xing＇an Range-Zhangguangcai Range polymetallic ore-forming belt,is mainly hosted in monzogranite. According to mineral assemblages,alteration and crosscutting relationships of the veins,the mineralizing stages of the Luming molybdenum deposit can be divided into three： 1） potassium silicification disseminated mineralization stage; 2） silicified stockwork mineralization stage; 3） chlorite-carbonate stage. Aqueous,gaseous,CH4（ CO2）-bearing and daughter mineral-bearing inclusions coexist in molybdenite quartz veins of Luming molybdenum deposit. The homogenization temperatures of aqueous inclusions are from 133 to 425℃,salinities of 1. 6% - 16. 1% NaCleqv. Gaseous inclusions with homogenization temperatures of 243 - 500℃,salinities of 1. 2% - 14. 1% NaCleqv. Daughter mineral-bearing inclusions with homogenization temperatures of 297 -449℃,salinities of 38. 2% - 53. 1% NaCleqv. CH4（ CO2）-bearing fluid inclusions by laser Raman spectroscopic analysis confirmed that the components of bubble phase are dominated by CH4,a few containing a small amount of CO2,with homogenization temperatures of 334 to 437℃. δ34S range of 4. 5‰ - 5. 7‰,shows the sulfur comes mainly from magmatic hydrothermal ore-forming fluid. The hydrogen and oxygen isotope data fall near the magmatic water and drift to the meteoric water in the δD-δ18OH2Odiagram,indicating that ore-forming fluids in main mineralizing stages were magmatic water and mixed with a small amount of meteoric water. The trapping pressures of fluid inclusions are estimated to be 30 - 90 MPa,and consequently corresponding to a depth of 3 to 9km. The ore-forming fluid was initially a single H2O-NaCl-CH4（ CO2） supercritical fluid system with high temperature and medium salinity separated from the magma chamber. The ore-forming fluid boiling happened and multiple types of fluid inclusions captured due to reduced pressure and mixed with different fluids. With the continuous evolution of the fluid an

关 键 词：流体包裹体 成矿流体 成矿机制 鹿鸣钼矿床 黑龙江 

分 类 号：P618.65[天文地球—矿床学]