湖南瑶岗仙石英脉型黑钨矿床成矿流体特征  

CHARACTERISTICS OF ORE-FORMING FLUID IN YAOGANGXIAN QUARTZ-VEIN WOLFRAMITE DEPOSIT,HUNAN PROVINCE

作　　者：董少花[1,2] 毕献武[1] 胡瑞忠[1] 陈佑纬[1] 陈恒[1,2] 

机构地区：[1]中国科学院地球化学研究所矿床地球化学国家重点实验室,贵州贵阳550002 [2]中国科学院研究生院,北京100049

出　　处：《矿物岩石》2011年第2期54-60,共7页Mineralogy and Petrology

基　　金：国家自然科学基金(40373020);国家重点基础研究发展计划(973)项目(2007CB411404)

摘　　要：利用红外显微镜对湖南瑶岗仙石英脉型黑钨矿床中不透明矿物黑钨矿的流体包裹体以及黑钨矿共生的透明矿物石英中的流体包裹体进行显微测温对比分析,结果表明,黑钨矿中的原生流体包裹体有富液体包裹体、纯液体包裹体和富气体包裹体等,其均一温度范围大致在230℃~320℃,平均温度为281℃;冰点-4.2℃^-12.9℃,盐度6.74%~16.80%溶液。石英中流体包裹体主要为富液体包裹体,其均一温度范围大致在202℃~273℃,平均温度为240℃;冰点-0.5℃^-4.1℃,盐度为0.88%~6.59%溶液。黑钨矿形成时捕获的流体属于中温、中等盐度、低密度的流体,石英形成时捕获的流体属于中低温、低盐度、低密度的流体。通过黑钨矿中流体包裹体的显微测温结果及前人研究成果分析显示,成矿流体主要来自岩浆,流体演化经历了自然冷却、混合作用等过程,这些过程可能是钨沉淀的有效机制。The petrography and temperature from the fluid inclusions in the opaque minerals in the Yaogangxian quartz-vein wolframite deposit are studied and tested under infrared microscope,and correlated those with the fluid inclusions in the transparent mineral quartz coexisted with wolframite.There are three dominant types of fluid inclusion in wolframite,liquid-rich inclusion,gas-rich phase inclusion and pure liquid fluid inclusion.Homogenized temperature of fluid inclusions in wolframite ranges from 230 ℃ to 320 ℃,with a mean temperature of 281 ℃ and the salinity ranges from 6.74 to 16.8 wt%NaCl eqv.The major fluid inclusions in quartz are liquid-rich inclusion with their homogenized temperature ranging from 202 ℃ to 273 ℃ and with their salinity from 0.88 to 6.59 wt%NaCl eqv.These features reveal that the ore-forming fluid of wolframite is characteristic of medium temperature,medium salinity and low density,while the fluid in quartz belongs to low temperature,low salinity and low density.According to microthermometry data of the fluid inclusions and previous study,it is considered that the ore-forming fluid in Yaogangxian tungsten deposit may come from magma,and their evolutions are composed of cooling and mixing processes,which may be the efficient mechanism leading to the deposition of wolfram.

关 键 词：瑶岗仙 石英脉型黑钨矿床 流体包裹体 红外显微测温 成矿流体 

分 类 号：P618.67[天文地球—矿床学]