| Wudaogou tungsten deposit is located in the eastern part of Hunchun city,Jilin Province,The tectonic location is in the plate boundary of the subduction of the Pacific plate from the Pacific plate to the Asian continental plate,which is an important part of the circum Pacific tectonic mag-matic metallogenic belt.Many tectonic magmatic events occurred since the Mesozoic,which result-ed in strong mineralization of Cu,Au,W,Mo and other polymetallic mineralization in Yanbian area.Based on the field investigation,this paper discusses the genesis of the Wuduogou tungsten deposit which is relatively weak by studying the metallogenic background,the geological characteristics of the deposits and the geochemical characteristics of the deposits.And further summarizes the metal-logenic geological conditions,prospecting signs and mineralization enrichment laws,also provides the theory for further exploration of tungsten ore in the mining area.Studies on deposit geology shows that:Firstly,Wudaogou tungsten deposit occurs in the inner zone of the Late Hercynian granodiorite pluton with Wudaogou group of metamorphic rock contact zone and also is controlled by interlayer fracture zone and stannary is hosted Wudaogou group in Yangjingou and Xiangfangzi formation.Secondly,ore minerals are mainly scheelite,accompanied by a small amount of pyrrhotite and pyrite,arsenopyrite,etc.The gangue minerals consist of quartz,albite,biotite,actinolite,sericite,calcite and othercomponents.Thirdly,the wall rock alteration in-cludes silicification,sericitization,chloritization,albitization,actinolitization,carbonation,arsenopy-rite,pyritization etc.,which is closely related to scheelite mineralization are albitization and scheelite.Fourth,the structure of the ore is composed of the structure of parcel-milk drop,interstitial structure,metasomatic structure and so on.The ore structure is a vein-like structure and disseminated structure.Fively,the deposits are divided into two mineralization period: the hydrothermal period and the supergene stage.Among them,the magmatic hy-drothermal period from early to late can be further divided into three stages: quartz-scheelite-arsenopyritestage,quartz-scheelite-sulfide stage,quartz-calcite stage,while the first two stages are the main metallogenic stage.Study on the geological characteristics of the deposit are shown:firstly,The formation of the Wudaogou group has the characteristics of shoshonite(SHO)series,high K Calc alkaline(HKCA)series and calc-alkaline series.Secondly,Late Hercynian magmatic rocks and Late Indosinian-Early Yanshanian periods dikes show the characteristics of calc-alkaline series of typical orogenic granites.Thirdly,The main ore element W is associated with the middle and low temperature elements As,Sb,Hg and Ag,which reveals that the tungsten mineralization has many phases.Fourth,the geological characteristics of the deposit and the geochemical characteristics of the trace elements in the metallogenic related geology have shown that the source of the ore-forming material is multi source,Wudaogougou Group is the main source of mineral deposits in the deposit,and the rock mass provides some mineralization in addition to the heat source and fluid.Wudaogou tungsten deposit is characterized by multiple stages of mineralization,metallogenic epoch is the Late Hercynian(230~267.8Ma)and Late Indosinian-Early Yanshanian periods(178~197Ma).Wudaogou ore deposit belongs to the NaCl-H2O-CO2 hydrothermal system with me-dium temperature and low salinity,the ore-forming fluids are dominated by magmatic water,and a small amount of atmospheric precipitation is involved.The ore forming fluid decompression boiling cause the physical chemical system of ore fluid balance is destroyed,so that WO42-and Ca2+ formed in different mineralization types of scheelite in appropriate physical and chemical condition and different ore bearing rock andore bearing structure in different space.The formation mecha-nism of ore deposits is controlled by the stratigraphic-tectonic-magmatic metallogenic system.The genetic type of the deposit belongs to the stratabound-magmatic fluid of high temperature quartz vein type scheelite deposit,the geodynamic background of the formation of diagenesis and mineral-ization in the subduction of the Pacific plate to the Eurasian plate.Based on the deep analysis of the ore-forming geological conditions of the ore bearing area and the mining area,the prospecting signs are summarized,which further reveals that the deposit is controlled by "strata-rock mass-fracture".By continuing to carry out different levels of geological prospecting work,it is expected to find a larger ore body in the soil geochemical anomalies delineat-ed two prospecting areas. |
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