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.
Yorktown became a famous locale in 1781 after the surrender of the British troops which effectively ended the Revolutionary War. British forces in and around Yorktown dug a number of defensive earthworks that were sieged by American and French troops over a three-week period prior to the surrender on October 19th, 1781. In the early 21st […]
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 […]