Study On The Microstructure Of Quartz

The study area is located in the Danfeng area of Shaanxi Province.The geotectonic location is in the Dabie-Orogenic Belt of the Qinling Mountains,and is divided into the Kuanping Group,Erlangping Group,Qinling Group and Danfeng Group from north to south.In this study,Shangdan granitic mylonite was selected as the research sample.Granodioritic mylonite,granitic primary mylonite and mylonitized were collected to discuss the deformation of quartz at different deformation stages and multiphase minerals.The pure quartz domain of the sample delineated samples and the quartz domain affected by the two-phase minerals were compared experimentally.The presence and content of mica and feldspar in granitic mylonite were restricted to the deformation of quartz,and semi-quantitative analysis of different minerals Its degree of influence.Quartz is one of the most abundant minerals in the earth's crust.It is instructive for the study of tectonic kinematics to explore its deformation characteristics in different mylonite granites.Different two-phase minerals have different effects on quartz due to their different characteristics.For example,the connectivity of mica during deformation often inhibits or even blocks the growth of quartz and the development of later deformation,so different two-phase minerals are different.The influence mode of main phase mineral deformation has important research significance.The main method of the experiment is the electron backscatter diffraction(EBSD)test method,and the data analysis and processing uses the Mtex toolbox in Matlab.The study found that during the process of increasing the degree of deformation,the size of the quartz particles was greatly reduced,and the preferred crystal orientation(CPO)changed dynamically,gradually changing from the rhomb slip controlled by the original rock to the prism slip.However,when the two-phase minerals exist,the fabric is greatly disturbed,and it is very different from the fabric characteristics of the pure quartz domain,showing that the growth of quartz is greatly restricted,and it is found that different minerals inhibit quartz to different degrees,the effect of mica on quartz is stronger than that of feldspar on quartz.This may be because the connection of the mica domain can cause the concentration of strain,so the dense quartz fabric caused by early dislocations is destroyed.In addition,the CPO pole figure reflects the deformation temperature from 500 to 650°C.Combined with the microstructure characteristics and mineral deformation methods,it is speculated that the deformation environment of mylonite is mainly concentrated in the high greenschist facies to low amphibolite facies.