The Pangxidong fracture zone of Guangdong developing in south of Qinzhou Bay(Q)-Hangzhou Bay(H) juncture orogenic belt is an important structure controlling silver-gold deposits forming and also a significant window to see the tectonic evolution history of Q-H juncture orogenic belt. The mylonites from it are studied in this paper. It researches the fractal feature and mainly rheological parameters of dynamically recrystallized quartz grains in mylonites. Classical S-C fabrics are founded in mylonites. This NE-trending ductile shear zone is dextral shear according to studying σ-rotational porphyroclasts. Under the light microscope

undulatory extinction

core-mantle structure

sub grain

dynamic recrystallization

elongated single crystal and quartz ribbon are observed. The widespread dynamic recrystallization of quartz grains which are slightly elongated and directed have jagged and indented boundaries. The ductile deformation temperature of rocks in Pangxidong fracture zone is approximately 600℃ through fractal analysis and microscope observation

which presents low amphibolite facies. The quartz recrystallized grain size paleopiezometer suggests that the differential stress is 9.1-10.7MPa(lower limits). The extrapolation of quartzite flow laws shows the strain rate is under 10

-13.8

s

-1

. These rheological parameters can be used in a deeper research on the ductile deformation process of Pangxidong fracture zone.