Study On The Rocks And Ore Controlling Structures In Lawu Cu-Zn Deposit,Dangxiong,Tibet

Based on Predecessor’ s work.the author gathered geologic information,made field investigation,data collection and laboratory analysis.With the help of theories of structural geology, Petrology,mineral deposit geology,geochemistry,structure of ore field,obtains from the geotectonic background, focused on the relationship between stratigraphy,tectonics,igneous rocks and mineralization.Analysis the tectonic evolution,geological features and avariety of ore-controlling factors of mine,to proof the relations of space and time of structure and mineralizes,summarized the regularity of ore formation and structure mineralization model.The research shows that the the formation of Cu-Pb-Zn strictly controlled by the structure.According to the different parts or form of structures, the ore can be divided into upright cylindrical and layered or stratoid orebody.Now there are seven main orebody, which number as Ⅶ、Ⅶ-1、Ⅶ-2、Ⅹ、Ⅹ-1、Ⅰ and Ⅱ, distributed in the north of Lawu fault F3and carbonate rocks nearby.By the study of main structures of Lawu deposit,scilicet as Lawu fault F3and Riyinna anticline:the anticline is structure before pluton emplacement,mainly is controlled by N-S compressional stress,Granites emplaced in the core of the anticline and vulnerable parts,manifested as batholith or dykes.The fault F3act as hydrothermal emplacement channel,ore fluids contact metasomatic with texture layer and mineralize through fracture emplacement.Characteristics and mechanism of controlling ore structures are analyzed in the text:Lawu fault and its secondary NE faults are important metallogenic tectonic factor, Followed by contact zone structure of granite and wall rock and the interlayer fracture of wall rock.Lawu fault is structure before mineralization,function as passage ways for ore fluid;its secondary NE faults and the interlayer fracture of wall rock are the main ore-hosting structures,which also control the orebody morphology;contact zone structure is structure in mineralization, is structures as passage ways for ore fluid and ore-hosting structure,form of scheelite ore body is controlled by contact zone shape.Tectonic evolution and study on mineralizational structure system, forming and evolvement of controlling ore structures in the Lawu ore field is concluded by a model of ore-controlling structure.