A number of sinistral ductile shear belts are exposed in Yantou Mountain and Taoyuan areas from the Feidong segment of the Tanlu fault zone. The lithology is mainly mylonite and mylonitic gneiss, and the rocks are strongly deformed. Through detailed field observation and indoor analysis, it is found that the geometric shape of Yantou Mountain and Taoyuan area in the north of Feidong to be an antiform, and its hinge strikes NE?SW, the axial plane trends to SE. And following the shape of the antiform, the lithology shows certain regularity and symmetry. The paleo?stress direction and kinematic vorticity study show that the structure in the study area is mainly squeezed from the north?south direction, and the vorticity value Wk is between 0.73 and 0.90, indicating that the ductile shearing activity in the region is dominated by simple shear. The detailed structural deformation analysis of the deformed rocks in the area, including the fractal characteristics of quartz, the estimation of metamorphic deformation temperature, the calculation of differential stress and strain rate. The results show that the boundary of dynamically recrystallized quartz particles in the study area has a statistical self-similarity, the fractal dimension D is between 1.111 and 1.187, and the metamorphic deformation temperature is concentrated between 520℃ and 610℃, which is the metamorphism of the high greenschist facies to the low amphibolite facies. The differential stress Δσ of the ductile shear zone is between 18.493 MPa and 95.266 MPa, and the strain rate ε ranges from 5.418×10-15 s-1 to 4.748×10-11 s-1. Comparing the above parameters, it is found that the rock is strongly deformed and the metamorphic deformation temperature is high near the core of the ductile shear zone and the hinge zone of the antiform. By comparing the above parameters, it can be found that the rock is strongly deformed and the metamorphic deformation temperature is high near the core of the ductile shear zone and the hinge zone of the antiform. The dynamic recrystallized quartz particles size is small, the fractal dimension is large, and the differential stress and strain rates are large, away from the core of the ductile shear zone and the hinge zone of the antiform are opposite. In this paper, the detailed research on geometry, kinematics and microstructural deformation analysis is of great significance for further understanding of the tectonic style and evolution process of the Tanlu fault zone and even the large ductile shear zone.
Yuan Fang Song Chuanzhong Lin Shoufa Li Jiahao Li Zhenwei Wang Yangyang Li Zhenqiang Chen Shouwen. Study on the structural deformation characteristics of Yantou Mountain and Taoyuan area in Feidong section of Tanlu fault zone[J]. Chinese Journal of Geology, 2020, 55(1): 109-121.