新疆西天山查汗萨拉金矿床流体包裹体特征及稳定同位素研究  

Fluid Inclusion Characteristics and Stable Isotope Composition of the Chahansala Gold Deposit,Western Tianshan,Xinjiang,China

作　　者：罗小平[1] 薛春纪[2] 李建全 王伟[1] 李天虎[1] 彭桥梁[1] 田海[4] 

机构地区：[1]西安地质矿产研究所,西安710054 [2]中国地质大学地质过程与矿产资源国家重点实验室,北京100083 [3]河南地质矿产勘查开发局第四地质探矿队,郑州450001 [4]中国建筑材料工业地质勘查中心宁夏总队,银川750000

出　　处：《地质学报》2011年第4期505-515,共11页Acta Geologica Sinica

基　　金：国家科技支撑计划(编号2006BAB07B01-02);高等学校学科创新引智计划(编号B07011);长江学者和创新团队计划(编号IRT0755)联合资助成果

摘　　要：查汗萨拉金矿是近年来在新疆西天山新发现的金矿床,位于依连哈比尔尕构造带西端,属构造角砾蚀变岩型金矿床。流体包裹体研究表明,查汗萨拉金矿石中的原生包裹体主要有两种类型:气液两相包裹体和富CO2三相包裹体。流体包裹体显微测温、盐度、密度及压力估算显示,气液两相包裹体均一温度为142~391℃,盐度为2.24%~7.73%,均一压力为0.274~16.35 MPa;富CO2三相包裹体均一温度为288~399℃,盐度为1.22%~2.39%,均一压力为187.0~240.7 MPa,具有中温、低盐度特点。成矿流体属CO2-H2O-NaCl型热液,成矿深度为1.1 km。成矿应力场转变导致的流体减压沸腾作用可能是查汗萨拉金矿金沉淀的主要原因。成矿流体稳定同位素组成δD为-92‰^-74‰,δ18O水为11.8‰~12.6‰,δ18CV-PDB为-8.92‰^-8.06‰,δ18OV-SMOW为13.45‰~17.18‰,H、O、C同位素组成说明查汗萨拉金矿床成矿流体可能为深部来源和变质建造水的混合。Chahansala gold deposit,a newly discovered gold deposit in Western Tianshan,locates in the west of Yilianhabi＇erga arc-trench belt of Late Paleozoic and belongs to tectonic breccia altered rock-type.Our study of the fluid inclusions indicates that there are two types of fluid inclusions in the Chahansla deposit： two-phase liquid-vapor inclusions and three-phase CO2-rich inclusions.The both types of fluid inclusions have homogenization temperatures ranging from 142℃ to 391℃ and 288℃ to 399℃ and the salinity ranging from 2.24% to 7.73% and 1.22% to 2.39%,and the homogenization pressure ranging from 0.274 MPa to 16.35 MPa and 187.0 MPa to 240.7 MPa,respectively.The fluid inclusions were characterized by low-meso temperatures and low salinity.Ore-forming fluid may be a CO2-H2O-NaCl system and ore-forming depth is about 1.1 km.The change of ore-forming stress field caused fluid immiscibility,and may lead to gold precipitation.The δD and δ18OV-SMOW of the hydrothermal gangue mineral quartz are-92‰^-74‰ and 11.8‰~12.6‰,respectively;the δ13CV-PDB and δ18OV-SMOW of the hydrothermal gangue mineral calcite are-8.92‰^-8.06‰ and 13.45‰~17.18‰,respectively.These stable isotopes studies reveal that the ore-forming fluid of the chahansala gold deposit was composed mainly of magmatic water and formational water.

关 键 词：查汗萨拉 金矿床 流体包裹体 稳定同位素 西天山 

分 类 号：P618.51[天文地球—矿床学]