The Relationship Between Tectonic Deformation And Gold Mineralization Along Shaocun And Xiongcun Village In Shexian County,South Anhui

The south of Anhui province is located in the junction of Cathaysia block and Yangtze plate,which belongs to the east section of the Jiangnan Orogen,and east section of Qin hang metallogenic belt,Hundreds of many kinds of metal point on a regional and ore deposits are mainly controlled by ductile shear zone.But the condition in the south of Anhui is difficult,not only the poor natural geographical conditions,also with the complex geological structure,low degree of the research,especially the infrastructure research is weak.So it become the urgent problem to further understand the characteristics and evolution of ductile shear zone,and its the corresponding relation of time and space with gold mineralization.Based on the detailed field geological survey between Shaocun village and Xiongcun village in Shexian county,south of Anhui province,this paper found that the study area has widely experienced ductile shear,deformation degree is strong and weak alternately,the fresh surface of wild outcrop has many kinds of deformation characteristics of the combination,such as obvious mylonite foliation,quartz and feldspar orientation stretching,the rotational porphyroclast formed from shearing.There are lots of a variety of kink and other small fold phenomenon,the invasion of the quartz vein,development of silicide phenomenon in the field,which indicate that the tectonic movement is the same time or late.The microscopic picture of orientation thin section shows that the quartz grain orientation arrangement,with ? type spot residue,S-C fabric,it directs the dextral extrusion shear,Part of bulging(BLG)recrystallized and core and mantle structure can be observed new crystal which with rules of boundary formed by the static recrystallization.Depending on the type of quartz recrystallization and sericite plastic deformation in the ductile shear zone is under the condition of high temperature deformation,superposition of the late deformation at low temperature.Through the results of EBSD experimental know that the type of slip system is given priority to the rhombohedral <a> slip system,deformation condition was medium and low temperature,but the variation is small,part of the section experienced the low temperature deformation in the later.By using extremely Moore circle method,this paper has estimated the directional samples of kinematic vorticity,the salt-male village section mainly for pure shearing action.The kinematic vorticity is estimated by means of the Polar Mohr constructions,most number is less than 0.71,which get the pure shear force was dominant in the section of Shaocun village and Xiongcun village.Combined with the element distribution in ductile shear zone geochemical profile and the intensity of tectonic deformation,it is obviously that in the location of the tectonic deformation degree is strong,Au element enrichment phenomenon is not obvious,but the mineral is enriched in where the deformation degree is weak.Analysis the reason,the location of strong tectonic deformation degree has big pressure,it makes the ore-bearing hydrothermal flow to the low pressure area along the tectonic fault zone.So,the ductile shear zone is to provide more space and more ore-bearing hydrothermal migration channel,rather than the main ore-controlling factors.The formation of the ductile shear zone in Shaocun village and Xiongcun village is caledonian period,which is related to the caledonian stage uplift structure in south China.The basement rocks were began to ductile deformation as a result of the uplift structure in the depths of the earth,which had experienced from high temperature to low temperature effect,after the brittle deformation;the rocks were pushed to the surface by thrust nappe in the yanshan epoch.