Figure 21

Experimentally deformed quartz aggregates

Figure caption

Experimentally deformed quartz aggregates

starting materials / semi-brittle & regime 1 / regime 2 / regime 2 & 3 / annealing

21

HQ, shortened 50% at 700°C, 10-5/sec and 1200 MPa, in the semi-brittle flow regime

The temperature is too low for either dislocation climb or grain boundary bulging recrystallization. Gliding dislocations rapidly tangle, creating high density tangles and thus strain hardening. Eventually the stress becomes high enough to nucleate cracks. The combination of distributed dislocations plus microcracks produces extremely strong and patchy undulatory extinction in most grains. In addition many grains develop multiple grain-scale faults, marked by strong narrow deformation bands and grain boundary offsets. (CQ10)

		Experimentally deformed quartz aggregates
		Figure caption

	Experimentally deformed quartz aggregates	starting materials / semi-brittle & regime 1 / regime 2 / regime 2 & 3 / annealing


21		HQ, shortened 50% at 700°C, 10-5/sec and 1200 MPa, in the semi-brittle flow regime The temperature is too low for either dislocation climb or grain boundary bulging recrystallization. Gliding dislocations rapidly tangle, creating high density tangles and thus strain hardening. Eventually the stress becomes high enough to nucleate cracks. The combination of distributed dislocations plus microcracks produces extremely strong and patchy undulatory extinction in most grains. In addition many grains develop multiple grain-scale faults, marked by strong narrow deformation bands and grain boundary offsets. (CQ10)