Hylas Zone Mylonite


This micrograph illustrates a mylonite from the Hylas Zone in the eastern Piedmont ~5 km west of Doswell, Virginia.  The rock is characterized by a well-developed foliation with elongate quartz ribbons (transparent grains) and feldspar porphyroclasts.  The rock originally was a granodiorite that was strongly deformed and sheared, under ductile conditions, into a mylonite. Checkout […]