Deformation-Induced Recrystallization Due to Progressive Misorientation of Subgrains, with Special Reference to Mantle Peridotites

The variation with strain of the misorientation between adjacent subgrains has been investigated in the olivine crystals of mantle peridotites naturally deformed at high temperatures. It is found that the misorientation of subgrains increases with strain up to about 15°, when the subgrains can be considered as independent grains. Evidence of this recrystallization "in situ," which does not involve grain-boundary migration, has been found in equigranular recrystallized peridotites: it is possible to find local domains where the grains have orientations traceable to subgrains of former deformed grains.