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《Acta Petrologica Sinica》 2008-05
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Ore-fluid geochemistry of the JO orebody,Jinchang gold deposit, Heilongjiang province,China.

ZHANG Yu~1 LAI Yong~(1**) QING Min~(2,3) WANG YanZhong~4 XU JiaJia~1 1.Laboratory of Orogen and Crust Evolution,Peking University,Beijing 100871,China 2.Gold Geological Institute of Armed Police Force,Langfang 065000,China 3.KLMD,Guangzhou Institute of Geochemistry,Chinese Academy of Sciences,Guangzhou 510640,China 4.Team 1 of Gold Branch of Armed Police Force,Mudanjiang 157000,China  
The Jinchang gold deposit,located in Dongning County,Heilongjiang Province,is a giant deposit that has been discovered recently,with resource up to 86 tons of gold.Occurring in the Jilin-Heilongjiang Metallogenic Belt in the eastern Central Asia Orogenic Belt,it is a complex ore-system possibly including porphyry-,explosive breccia- and epithermal-styles.The ore-system is associated with Mesozoic intermediate-acidic volcanic-subvolcanic rocks.The J0 orebody is regarded to be of explosive breccia-type. Studies in ore geology and isotope and fluid inclusion geochemistry show that the ore-forming process of the J0 orebody includes three stages,the early,middle and late stages,characterized by mineral assemblages of quartz—pyrite,quartz—polymetallic sulfides and quartz—carbonate,respectively.Most of the native gold grains are observed in the middle-stage minerals,and next in the early-stage pyrite.The initial ore—fluids were magmatic in origin and characterized by high temperature,high salinity,high oxygen-fugacity and high content of CO_2.Fluid-boiling resulted in release of volatiles such as CO_2 and decrease in oxygen-fugacity,causing rapid precipitation of sulfides and native gold in middle stage.Meteoric water input made the late-stage fluids dilute,CO_2-poor and epithermal,and slightly contribute to Au-mineralization.The J0 orebody of the Jinchang gold deposit is holistically an intrusion- related,shallow-developed(633m~2736m),high salinity(11.70%~37.81% NaCl.eq)and medium-to-high temperature(238.3 ~425.7℃)hydrothermal ore-system.The ore-system,characterized by high-content of CO_2,must be developed in extensional regime of a thickened eollisional orogen,instead of a magmatic arc related to oceanic plate subduction.
【Fund】: 国家自然科学基金项目(40672059)资助
【CateGory Index】: P618.51
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