Naturally deformed quartz-rich rocks

 

Grain boundary migration recrystallization

Naturally deformed quartz-rich rocks

 

undeformed / semibrittle & bulging recrystallization / subgrain rotation recrystallization / grain boundary migration recrystallization

 

List of microstructures

 

 

 

 

22

 

Mica-rich Heavitree quartzite showing by grain boundary migration recrystallization; mica grains pin the boundaries of recrystallized quartz grains.

25

 

Less micaceaous Heavitree quartzite; note larger, equant recrystallized grains.

27

 

Chert deformed and recrystallized at greenschist conditions; grain growth was greater in pure quartz regions.

28

 

Chert deformed at greenschist conditions, showing that dynamic recrystallization can produce an increase in grain size.

29

 

Chert deformed and recrystallized at greenschist conditions. Grain size depends on purity; coarser grain size region represents quartz veins.

30

 

Mica fish and oblique elongate recrystallized quartz grains in quartz mylonite, indicating dextral shear.