湘南新田岭大型钨矿流体包裹体地球化学特征  

Fluid-inclusion geochemistry of the lage-sized Xintianling tungsten deposit, Hunan Province, China

作　　者：双燕[1,2] 龚业超[1,2] 李航[1,2] 田旭峰 毛玲玲[1,2] 陈威[1,2] 

机构地区：[1]重庆地质矿产研究院外生成矿与矿山环境重庆市重点实验室,重庆400042 [2]煤炭资源与安全开采国家重点实验室重庆研究中心,重庆400042 [3]湖南省湘南地质勘察院,湖南郴州423000

出　　处：《地球化学》2016年第6期569-581,共13页Geochimica

基　　金：国家自然科学基金(41003024);重庆市科委自然科学基金(cstc2012jj A00021);重庆市国土资源和房屋管理局科技项目(CQGT-KJ-2014009)

摘　　要：新田岭大型钨矿床位于湘南骑田岭复式花岗岩体东北侧，与芙蓉超大型锡多金属矿床南北相对。本文对新田岭大型钨矿床进行了系统的流体包裹体地球化学和H-O同位素研究。研究结果表明，该矿床中白钨矿阶段流体包裹体类型主要为含C02两相包裹体、富含C02三相包裹体和气液包裹体，C02包裹体均一温度为264～479℃，盐度为0．22％～6．13％，C02的摩尔分数为0．09～0．62，气相组分为C02、CH4和H20。气液包裹体盐度为1．39％～11．37％，均一温度为398～479℃，为NaCl-CaCl2-H20水溶液体系。硫化物阶段包裹体的盐度为13．55％～17．74％，完全均一温度范围为139～346℃。成矿流体压力为30-120MPa。成矿流体由富含CO2的低盐度热液体系向不含CO2、中高盐度的热液流体演化，H、O同位素组成显示成矿热液流体具有岩浆来源的特征。钨在溶液中以钨酸的形式稳定迁移度，岩浆热液与含碳围岩发生水岩反应可能是新田岭白钨矿形成的主要机制。The Xintianling tungsten deposit is a large-sized skarn and vein-type tungsten-molybdenum polymetallic deposit located in the northeastern Qitianling pluton. Studies on the fluid-inclusion and H-O stable isotope geochemistry of the scheelite-stage and sulfide-vein stage ores in the Xintianling deposit have been carried out, with an attempt to better understand the tungsten mineralization mechanism and its genesis relationship with the Qitianling pluton. Three types of fluid inclusions have been observed, namely aqueous two-phase inclusions, CO2-bearing three-phase inclusions and CO2-bearing two-phase inclusions. Homogenization temperatures of fluid inclusions in the scheelite-stage ores range from 264℃ to 479℃. The ore-forming fluids have the composition of the CO2-CH4-NaC1-H20 system with a low salinity （0.22%-11.37%）. Fluid inclusions in the sulfide-stage ores have the homogenization temperatures ranging from 139℃ to 346℃, with a salinity range of 13.55%-17.74%. The H-O stable isotope data indicate that the mineralization fluids are dominated by magmatic fluids. It is concluded from fluid-inclusion studies that the reaction between CO2-bearing hydrothermal fluids and wall rocks is probably the major mechanism of formation of sheelite in the Xintianling deposit.

关 键 词：流体包裹体 H-O同位素 花岗岩 新田岭钨矿 

分 类 号：P59[天文地球—地球化学]