新疆西南天山萨瓦亚尔顿金矿床地质特征及成矿作用  

Geological characteristics and metallogenesis of Sawayaerdun gold deposit in southwest Tianshan Mountains, Xinjiang

作　　者：杨富全[1] 毛景文[1] 王义天[1] 李蒙文[2] 叶会寿[1] 叶锦华[3] 

机构地区：[1]中国地质科学院矿产资源研究所,北京100037 [2]中国地质科学院,北京100037 [3]中国地质调查局发展研究中心,北京100037

出　　处：《矿床地质》2005年第3期206-227,共22页Mineral Deposits

基　　金：国家重点基础研究发展规划项目(编号2001CB409807;G1999043216);国土资源大调查项目(200413000026的资助

摘　　要：根据大量的实际工作,并结合前人的研究成果,详细介绍了萨瓦亚尔顿金矿床的成矿地质背景和矿床地质特征,通过流体包裹体和同位素研究,对萨瓦亚尔顿金矿的成矿作用进行了深入讨论。研究结果表明,流体包裹体类型主要为气液两相包裹体,其次为富液相包裹体、富气相包裹体、含NaCl子晶多相包裹体和含液相CO2的三相包裹体。成矿流体为中低温(78~355℃)、中低盐度〔w(NaCleq)2.57%~22.10%〕的H2O_NaCl_CO2_CH4体系。硫化物的δ34S值变化于-3.0‰^+2.61‰,平均值为0.07‰,暗示硫来自地幔或与地幔相关的岩浆。白云石和菱铁矿的δ13CPDB值为-5.4‰^-0.6‰,表明成矿物质来自地幔及海相碳酸盐岩。氢和氧同位素显示成矿流体主要来源于大气降水,并混合少量岩浆水。萨瓦亚尔顿金矿与乌兹别克斯坦穆龙套金矿和吉尔吉斯斯坦库姆托尔金矿具有相似性,但它在浅成中_低温条件下成矿,且金、锑共生。物理化学条件和流体成分的改变、水_岩交换作用及流体的不混溶作用在成矿过程中起了重要作用。The Sawayaerdun gold deposit in Wuqia County of southwest Xinjiang occurs in Upper Silurian and Lower Devonian epimetamorphic carbonaceous turbidite, with the host rocks being carbonaceous phyllites, metasandstone and metasiltstone. Gold mineralized zones and orebodies are controlled by the brittle-ductile shear zone. Fluid inclusions in the Sawayaerdun gold deposit can be divided into two-phase vapor-liquid H_2O inclusions, liquid-rich H_2O inclusions, vapor-rich H_2O inclusions, daughter mineral-bearing polyphase inclusions and three-phase CO_2-type inclusions, of which two-phase vapor-liquid H_2O inclusions seem to be the main type. The ore-forming fluids are of the middle-low temperature (78～355℃) and low-middle salinity 〔2.57%～22.10% (w(NaCl_(eq)))〕 H_2O-NaCl-CO_2-CH_4 system. The δ^(34)S values of sulfides associated with gold mineralization range from -3.0‰ to +2.61‰ with a mean of 0.07‰, indicating that sulfur was derived from the mantle or the mantle-related magma. The δ^(13)C_(PDB) values of dolomite and siderite from the Sawayaerdun gold deposit range from -5.4‰ to -0.6‰, suggesting that carbon mainly came from the mantle and marine carbonate rocks. Hydrogen and oxygen isotope studies show that the ore-forming fluids were mainly derived from meteoric water, with a minor part from magmatic fluids. The Sawayaerdun gold deposit resembles the Muruntau gold deposit in Uzbekistan and the Kumtor gold deposit in Kyrgyzstan in geological setting, metallogenic characteristics and ore-forming mechanism. Nevertheless, the Sawayaerdun gold deposit shows some particularities: the ore-forming process is characterized by epizonal mineralization, and the association of medium-low temperature elements such as gold and antimony makes up the most prominent feature. Changes in physico-chemical conditions of ore fluids and fluid compositions, water-rock exchange and immiscibility of ore fluids played important roles in the ore-forming process of the Sawayaerdun gold deposit.

关 键 词：地质学 成矿作用 含碳岩系 脆-韧性剪切带 萨瓦亚尔顿 新疆 

分 类 号：P618.51[天文地球—矿床学]