Page 60 - Microtectonics

48 3 · Deformation Mechanisms

Fig. 3.33. Gneiss with lobate grain boundaries, especially between quartz and feldspar. The rock has been deformed at high-grade metamor-
phic conditions and GBM-recrystallisation affected quartz and feldspar. St. Barthélemy Massif, Pyrenees, France. Width of view 4 mm. CPL

Fig. 3.34.
Four microstructures, which
indicate movement direction
of a migrating grain boundary
during GBM recrystallisation
(after Jessell 1987). Solid arrows
indicate the movement direction
of the grain boundary by growth
of the light grain into the shaded
grain. Further explanation in text