Deformed marbles from the Mt. Lofty Ranges, South Australia, have microstructures characterized by deformed relics of calcite interspersed with much finer-grained, recrystallized calcite, and with minor quartz and diopside. The deformed calcite relics contain numerous subgrains, and show abundant evidence of strain-induced migration of twin and grain boundaries. New calcite grains have nucleated and grown preferentially along twins (especially at twin intersections), at grain and kink-like boundaries, and apparently randomly inside-deformed relics. Optical microstructural evidence suggests that dynamic (syntectonic) recrystallization has taken place, along with some static recrystallization. Probable mechanisms for the initiation of recrystallization include bulge nucleation and subgrain nucleation.