A Resource for Information on the Commonwealth's Geology
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Chopawamsic Gneiss
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 […]
What’s New in Virginia Geology
Virginia is for Lavas- The Catoctin Formation
Many of the highest peaks in Shenandoah National Park (including Hawksbill, Stony Man, and Hightop Mountain, just to name a few) are underlain by distinctive bluish-green rocks that were once ancient lava flows (Virginia is for Lavas!), and are part of a geologic unit known as the Catoctin Formation. From the presidential retreat at Camp David to Jefferson’s […]