Naturally deformed quartzo-feldspathic rocks
Figure caption
weak deformation (Mulwaree) / strong deformation (Mulwaree) / mylonites (Redbank) / ultramylonites (Redbank)
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Quartzo-feldspathic mylonite developed at greenschist conditions; feldpars fractured, quartz deformed by regime 2 dislocation creep.
Mylonite developed in quartzo-feldspathic aplite, deformed at greenschist grade in the Redbank shear zone. Quartz grains form thin ribbons wrapped around K-feldspar porphyroclasts. Some quartz ribbons may represent domains between kink bands rather than entire original grains. The ribbons contain well-developed subgrains and the recrystallized grains at their margins have approximately the same size, indicating deformation by dislocation creep regime 2. The feldspar porphyroclasts show some fracturing, the development of deformation-induced twin lamellae, and strong undulatory extinction. (499 A)