Zircon ages of felsic volcanic rocks in the upper Precambrian of the Blue Ridge, Appalachian mountains
Five zircon samples from Pennsylvania, Virginia, and North Carolina yield discordant uranium-lead ages which suggest an original age of 820 million years and an episodic lead loss at 240 million years. The indicated age of lead loss is interpreted as the age of movement of the Blue Ridge thrust sheet.
North Carolina, Pennsylvania, Virginia↗