I took a trip down to Charlottesville this week for a couple of meetings, and I made time along the way to capture two new GigaPans of the lovely exposures of Catoctin Formation greenstone at Rockfish Gap, where Interstate 64 traverses the Blue Ridge. This is very close to the southernmost tip of Shenandoah National Park, and at the northern terminus of the Blue Ridge Parkway.
The Catoctin is an interesting unit – it was erupted during the Neoproterozoic as a series of flood basalts (the trigger was the rifting of the supercontinent Rodinia and the opening of the Iapetus Ocean basin), and then was metamorphposed and deformed during the late Paleozoic Alleghanian Orogeny (the collision of ancestral Africa with ancestral North America, and the shoving upward of the youngest incarnation of the Appalachian Mountains). If you explore these GigaPans, you’ll find chlorite-rich greenstone with internal boudinaged epidotized sandstone pods and a pervasive cleavage.
It was windy and cold up there, and I had to brave ticks and briars to take these photos, but I’m pleased with the results. They’ve been added to the Mid-Atlantic Geo-Image Collection, which is now close to 300 GigaPans.
Here’s a link to an excellent in-depth examination of these rocks by Chuck Bailey at the College of William and Mary, and even a video filmed on location.