新疆北部VMS矿床地质特征及成矿规律

VMS矿床是中亚造山带的重要矿床类型，在新疆中亚造山带（即新疆北部）主要分布于阿尔泰和东天山的阿舍勒、克兰、麦兹和卡拉塔格矿集区.含矿层位主要有下?中志留统红柳峡组、上志留统?下泥盆统康布铁堡组下亚组和上亚组、下?中泥盆统阿舍勒组和下石炭统小热泉子组海相火山沉积岩系.矿区发育喷流岩，如含铁碧玉岩、重晶石、硅质岩、铁锰质大理岩、黄铁矿层、绿泥石岩.VMS成矿系统中发育多种矿化类型，“双层结构”（层状或透镜状矿体和补给通道相脉状矿体）是其中之一，还有与火山热液有关的脉状矿化、与次火山热液有关的脉状和浸染状矿化.VMS矿床形成于3个成矿期，即早?中志留世（428~438 Ma）、早?中泥盆世（379~413 Ma）和早石炭世（332~359 Ma）.硫来自下伏火山岩、海水硫酸盐无机还原作用和硫酸盐细菌还原作用.成矿流体以中低温（300~120 ℃）低盐度（2%~10% NaCl_eq）为特色，成矿流体为深循环海水混合不同比例的岩浆水.VMS成矿系统中由于受火山机构、岩相、矿化类型、矿化部位、成矿流体来源、物理化学条件等因素影响，造成了成矿元素组合复杂. 

VMS Deposits in the Northern Xinjiang: Geological Characteristics and Metallogeny

Volcanogenic massive sulfide (VMS) is one of the most important deposit types in the Central Asian Orogenic Belt (CAOB). In the CAOB in Xinjiang (northern Xinjiang), VMS deposits are mainly distributed in the Ashele, Kelan, Maizi, and Kalatag ore dense districts of the Altay and the East Tianshan. The orebodies occurr in marine volcanic sedimentary rocks from the Lower-Middle Silurian Hongliuxia Formation, the Upper Silurian-Lower Devonian Kangbutiebao Formation, the Lower-Middle Devonian Ashele Formation, and the Lower Carboniferous Xiaorequanzi Formation. Exhalation rocks are developed in these ore districts, such iron-bearing jasper rock, barite, siliceous rock, ferromanganese marble, pyrite layer, and chlorite rock. There are many mineralization types developed in VMS metallogenic system, including the "two-layered structure" (layered/lenticular type and vein type from recharge zone), vein type related to volcanic hydrothermal fluids, and disseminated/vein type associated with sub-volcanic hydrothermal fluids. The VMS deposits in Xinjiang formed in three metallogenic periods: the Early-Middle Silurian (428-438 Ma), the Early-Middle Devonian (379-413 Ma), and Early Carboniferous (332-359 Ma). Sulfur of these deposits is derived from the underlying volcanic rock, inorganic sulfate reduction of seawater, and bacterial sulfate reduction. Ore-forming fluids are characterized by medium-low temperature (300-120 ℃) and low salinity (2%-10% NaCl_eq), and are deep-circulation seawater mixed with magmatic water in different proportions. The VMS metallogenic system is affected by volcanic structure, lithofacies, mineralization type, ore-forming fluids source, and physical-chemical condition, which results in a complex combination of mineralization elements.