The crystallographic preferred orientation of quartz and its applications

The crystallographic preferred orientation (CPO) of quartz aggregates can be developed by dislocation glide, twin glide, and oriented nucleation and growth, among which dislocation glide is the most important mechanism. Factors that can affect quartz CPO include temperature, strain rate, strain, differential stress, content of water, interaction among minerals in polymineralic rocks, and initial orientation. This paper summarizes and discusses quartz crystal deformation and slip systems, measurements and representations of quartz CPO, CPO patterns developed under various geological environments, and quartz CPOs' applications to interpreting shear sense, calculating value of kinematic vorticity number, determining the temperature of deformation, and deciphering deformation evolution history with the conclusion that those applications of quartz CPO patterns should not be relied on exclusively.