A Resource for Information on the Commonwealth's Geology
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 this blog post for more information on the Hylas Zone. Plain light micrograph.
This exposure in a pasture near Cuckoo exposes a poly-deformed hornblende and plagioclase-rich gneiss. Foliation in the gneiss has been refolded. Another interesting feature is the presence of garbenschiefer or “feather amphibolite.” This unusual texture is defined by stellate and featherlike hornblende clusters in the plane of foliation. Three amphibole species occur in this rock […]
On July 1, 2016, Governor Terry McCauliffe signed a bill into law that made nelsonite the first official state rock of Virginia. The initiative for this project was led by students from Piedmont Virginia Community College. Michelle Stanislaus and her classmates from their Historical Geology class and Government class ran the petition for this law starting […]