Some of the most unique rock formations in Shenandoah are greenstones: old lava flows that now cap many of the highest peaks in the park. These rocks preserve evidence of 570 million years ago, when two tectonic plates began to spread apart along a system of rifts thousands of miles long. Molten rock from deep within the earth rose through these rifts, eventually covering over 4,000 square miles on the earth’s surface. The lava flows filled in valleys and lapped up against hills and old, eroded mountains. These lava flows helped shape the Shenandoah of today, as the individual layers created flat “benches” and sheer cliffs that give peaks such as Stony Man a noticeably staircase-like texture. Big Meadows, a broad, near-flat area at high elevation, sits on the surface of one of these lava flows.
Lace up your boots and come explore the remains of one of these ancient volcanic rifts. This 2-hour, 2-mile Park Ranger-led hike starts at 10:00 a.m. every Monday, Thursday and Friday this fall, through October 30. Meet at Timber Hollow Overlook (mile 43.3). Click here for a full schedule of Fall Ranger Programs.