The Characteristics Of Ductile Shear Zone In Luoyuan Area Of Luo Nan County, Shaanxi Province And Its Control To Gold Deposit

The study area is located in the west of Xiaoqinling gold(molybdenum) metallogenicbelt,southeast to the Qinggangping-Jinduicheng deep fault,where adjacent to Jingduichengand faults,folds are well developed;magmatic hydrothermal activity is frequent.All geologicalconditions are good to mineralize.The thesis is on the basis of all former data collation andanalysis,through field investigation and indoor finishing,texting,using structural analysismethod,as Luoyuan goldern mine as the research center,use the regional tectonicsgeology,tectonic petrology science theory as the foundation,study on the characteristics ofgoldern ore controlling structure preliminarily.The main access as follows:(1)Summarize the regional geological,ore body,ore characteristics and the occurrencestate of gold.The types are quartz vein and structural altered rock in the working area with alarge scale and lens or bead shape,its ore is not uniform,more obvious change along the strikeand dip.(2)Define a regional ductile shear zone,show us a large scale,west from Longfenghill,east to Chenjiayuan,in north Qingggangping-Jinduicheng fault as the boundary and insourth Zhangjiaping-Bayuan fault.its15km long and5.1km width,the most width is6.3kmand the narrow is4.2km.the overall inclination is about300°-350°,and the dip angle isbetween35°-75°.By field investigation and indoor finishing,The auther study it ongeometry,kinematics and dynamics. Regional ductile shear’s main characteristics are:transpressional dextral shear stress, the maximum principal stress orientation is about295°∠20°,the value about84.1MPa,displacement about0.16km and about0.0814%totalamount stretch.(3)Preliminary study ore-controlling ductile and brittle shear zone in the workingarea,the auther find that the regional ductile shear zone changed to brittle and formed theore-controlling ductile and brittle shear zone in the local area.its compresso-shear dextralshear effect earlier and rocks in the band occurred obvious plastic deformation products toform tectonic schist,early mylonite,mylonite type plastic deformation products,but localtenso-shear role superposite to form some piece space.later brittle deformation was obviousand jointe comparatives developed transformating to the shear zone.(4)Luoyuan gold deposit occurs in the inner and outer contact zone of Luoyuan granitebody and Xionger Group volcano rocks and is strictlly controlled by regional ductile shearzone,granite and ore-controlling ductile and brittle shear zone.Regional ductile shear zonemake gold element migrated,transfered and to formed the first stage of gold enrichment.Affected by the regional ductile shear zone of transpressional shear and thevertical stress,granite intrusion;the granite body intrused in the volcano rocks of Xiongergroup,in the process,happened plastic deformation.,again, gold element migrated,transferedand to formed a second stage of gold enrichment.The ore-controlling ductile and brittle shearzone once again provided impetus for gold activates for its third migration,and providedchannel for ore-bearing hydrothermal migration,sedimentation,mineralization.it’s ore structureand ore-bearing structure.There,inner and outer contact zones of the regional ductile shear andLuoyuan granite where ore-controlling ductile shear belt outcropped is the area favorable forgold.