HT-LS Microfabric Evolution


First transient stage (0<g<1.5):
Blue and violet grains disappear whereas the volume proportions of yellow and magenta grains increase. We attribute this behavior to continuous reorientation of the grains´ crystallography into orientations that are favourable for intracrystalline gliding (i.e., easy glide orientations).
Note the formation of a stable, oblique grain SPO at angles of about 60° with respect to the SZB.

Second transient stage (1.5<g<6):
Grain boundary migration recrystallization is the predominant grain scale mechanism. The area proportion of the yellow grains, for example, increases significantly at the expense of  the area proportion of magenta grains. This behavior leads to a strongly domainal microfabric consisting of yellow and magenta domains.

Steady state (g>6):
The area proportion of yellow and magenta grains is strain invariant on the sample scale. On the grain scale, however, one can observe cyclical consumption and growth of individual grains (e.g., see magenta grains in the lower left hand corner).

Analogy:
This steady state microfabric in norcamphor is very similar to that of natural quartz mylonites deformed under upper greenschist to amphibolite facies conditions (see Fig. 12 in Herwegh & Handy, 1996)