The Characteristic Of The Ductile Shear Zone And Its Relationship With Gold Mineralization In Tianjingshan Gold Deposit Xiuning County, South Of Anhui Province

The Tianjingshan gold deposit is an important gold deposit in southern Anhui province, comprehensive research on which is significant for the future gold multi-metal ore-prospecting in southern Anhui. This deposit was controlled by the Huangmao-wucheng-tunxi ductile shear zone, thus ascertaining the relationship between the ductile shearing deformation and mineralization becomes a crucial requirement.Based on detailed field geological survey, this paper found the study region was covered by the ductile shear zone, but the strength of ductile shearing deformation has some differences on different region. The microscopic picture of orientation thinsection shows that the quartz in the deformation rock has experienced subgrain rotation and boundary migration recrystallization, some has experienced dynamic recover recrystallization. While the most feldspar is the rotational porphyroclast, the boundary of some feldspar has the fine grain of bulging recrystallization. The characteristic of microstructure indicates the ductile shear zone developed local high temperature deformation and general medium temperature deformation, subsequently superposed low-temperature deformation. The process of deformation was very complex. The marker of rotational porphyroclast indicates stretching shearing associated with some strike-slip shearing deformation. The kinematic vorticity is estimated by means of the Polar Mohr constructions, which get the simple shear was dominant in the ductile deformation. The result of quartz C-axis fabrics of deformed granite shows that the type of slip system is mainly the rhombohedral <a> slip system, partly subface <a> slip system. This result indicates the deformation environment was medium temperature metamorphism, deformation temperature was about 450-600 ° C. And the type of slip system of deformed clasolite is cylindrical<a> slip system, partly rhombohedral <a> and subface <a> slip system. This result indicates the deformation environment was medium-high temperature metamorphism, the low temperature deformation occurred in the later. The quartz C-axis fabrics of different samples indicates the characteristic of multi-stages deformation and dextral shearing deformation.Through the analysis of the relationship between the content of each element on geochemical profile with ductile shear deformation, it indicates that there is not obvious relationship between elements enrichment with ductile shear deformation intensity. However partial elements were accumulated more easily in contact tectonic belt. It is concluded that the ductile shear zone is not the main ore-controlling factor, but provides the space for ore accumulation and the migration pathway of hydrothermal ore. This deposit has undergone many stages before formation, and it is the result of a variety of ore controlling factors.Combining preview study with this paper’s conclusion about the ductile shear zone, we consider that this ductile shear zone was formed in the Caledonian uplifting period. In the process of uplifting, the stratum on both side of the basement had experienced ductile slip deformation along the weak structure surface, which eventually leads to the formation of this ductile shear zone. Subsequently, the ductile shear zone went through late-stage superimposed transformation and was thrusted to surface by the thrust-nappe structures in the Yanshanian period.