The Analysis On Metamorphic And Deformation Characteristics And Formation Environment Of Carbonate Mylonite Of Taowan Group

Taowan Group in the northern margin of the East Qinling orogenic belt with distribution of a set of carbonate mylonite, with obvious plastic deformation, the distribution and metamorphism and deformation characteristics of which was strictly controlled and affected by the Luonan-Luanchuan fault zone. According to the characteristics of intense activity of the Luonan-Luanchuan fault zone in late Caledonian Early Hercynian period, carbonate mylonite of Taowan Group was believed to be formed in the process of late Caledonian Early Hercynian tectonic activities of Luonan-Luanchuan fault zone. Therefore, environmental analysis on the formation of metamorphism and deformation features of the carbonate mylonite can reveal the kinematics and dynamics characteristics of tectonic activities of Luonan-Luanchuan fault zone in this period. In this paper, through detailed field observation and measurement, combined with microstructural analysis and temperature and pressure calculation, Taowan Group carbonate mylonite foliations is confirmed basic tendency of NNE, lineation grows well and shows kinematics characteristics of thrusting from N to S with sinistral shearing. Metamorphic facies is low greenschist facies, and deformation mechanism is plastic deformation based on dynamic recrystallization and fine-grained role. Mylonite formation temperature is 350～470℃, differential stress 10-40Mpa. Strain ellipsoid form displays Taowan Group for strong compression deformation. So the metamorphism and deformation of carbonate mylonite of Taowan Group was formed in a strongly oblique compressional collision environment, as a result of subduction and collision of Qinling micro-continental block to North China plate.