The Characteristics Of The Ductile Shear Zone And Its Relationship With Gold Mineralization In Jiumuqiu Ore District Of Xiuning County,South Of Anhui Province

The Jiumuqiu ore district is located in Xiuning County,Anhui Province,and Tianjingshan mining area are located in the Huangmao-Wucheng-Yuanfang-Shiershan ductile shear zone,The Tianjingshan gold deposit is an important gold deposit in southern Anhui province,has been confirmed for the ductile shear zone type deposit,However,the research work in the Jiumuqiu mining area is deficient and restricts the prospecting breakthrough.Therefore,it is important to find out the relationship between the characteristics of the ductile shear zone and mineralization in the Jiumuqiu mining area.This paper has carried out the work of revision,tectonic geochemical profile measurement,microstructure analysis,EBSD analysis and kinematic vorticity analysis in the study region,found that the study region is covered by the Yuanfang-Taoxi-Shaolian ductile shear zone,development in the formation of Changqian and Jingtan,which is the part of Huangmao-Wucheng-Yuanfang-Shiershan ductile shear zone.The length of the shear zone is about 20 km,and the width is about200~1500 m.The Yuanfang-Taoxi ductile shear zone shows NE distribution and the Taoxi-Shaolian ductile shear zone shows NEE distribution.Strong-weak zoning is macroscopically significant,The shear zone is characterized by obvious zonation: the shear zone developed in the Changqian formation is a weak deformation zone,the shear zone developed in the Jingtan formation is a strong deformation zone.The microstructure shows that the deformation rocks in the study area are characterized by the subgrain and undulatrory extinction of quartz,intragranular microfracture and rotational porphyrocla of feldspar.The experimental results of EBSD showed that the shear zone quartz deformation appears as subface <a> slip as the leading,most also showed the rhombohedral <a> slip,indicating its deformation temperature for low medium-temperature deformation in the early,late superposition of the low temperature deformation,shear zone has experienced at least two activities,reflecting the overall deformation temperature pressure environment is low temperature(? 400 ?).The calculation results of kinematic vorticity show that the study area of vortex kinematics ductile shear zone in value from 0.72 to 0.93,with a simple shear dominated,pure shear and accompanied by some of the general shear zone.The analysis results of metallogenic elements show that the Au element is mainly concentrated in the weak deformation zone of the ductile shear zone whichdevelopment in the Jingtan formation,and the enrichment of other elements is not directly related to the deformation of the ductile shear zone.Combining with above research results,this paper considers that the Yuanfang-Taoxi-Shaolian ductile shear zone which distributing in Jiumuqiu mining area,south Anhui province,is brittle ductile shear zone,provides beneficial structural space for fluid precipitation.It is the main reason for gold mineralization in ductile shear zone.After the formation of the gold deposit,the two nappe structures in the study area destroyed the deposit.