新疆托里县哈西金矿床包裹体-同位素地球化学及成因探讨

哈西金矿床位于哈萨克斯坦―准噶尔板块(Ⅰ级)唐巴勒―卡拉麦里沟弧带(Ⅱ级)西准南部扎依尔推覆体(Ⅲ级)玛依勒―哈图构造块体(Ⅳ)。通过矿床流体包裹体岩相学、显微测温学和包裹体激光拉曼光谱分析研究成矿流体性质,探讨矿床成因类型。研究结果表明,流体包裹体有气液两相、含纯液相和纯气相包裹体3种类型。气相成分以CO_2为主,其次是H_2O,总体属于CH_4-H_2O-CO_2体系;结合氢氧同位素地球化学特征(δD值为-60‰~-67.4‰;δ~(18)O值为14.3‰~16.8‰),以及稀土配分和同位素定年证据,确定本区成矿物质来于深部,成矿流体主要来源于火山-次火山岩浆热液,矿床形成于海西期具两阶段成矿特点,属中低温热液矿床。

Inclusion-isotope geochemistry and genesis of Haxi gold deposit in Tuoli of Xinjiang

Haxi gold deposit is located in Mayile-Hatu tectonic block (IV)of Zhayier nappe south of Western Junggar (III)in Tangbale-Kalamaili trench-arc belt (II),which belongs to Kazakhstan-Junggar plate (I). Based on petrographical and microthermometrical study on fluid inclusions of the deposit as well as laser Ra-man spectral analysis of inclusions,this paper conducted research on the characteristics of ore-forming fluid and the genetic type of the deposit.Results indicated that there were three types of fluid inclusions,namely gas-liquid type,pure liquid type and pure gaseous type.The gas-phase components are mainly CO 2 with less-er H 2 O,and overall they are deemed as part of CH 4-H 2 O-CO 2 system.Combined with the geochemical char-acteristics of H and O isotope (δD value ranges from -60‰ to -67.4‰,while δ1 8 O value from 14.3‰ to 1 6.8‰)and in consideration of rare earth element assemblage and isotopic dating evidences,it is verified that the ore-forming minerals are derived from the deep part of this region,and the ore-forming fluids mainly come from volcanic to sub-volcanic hydrothermal solution.The deposit is a medium-low temperature hydrothermal deposit which is formed during Hercynian period and is characterized by two-stage mineralization.