At Yellowstone’s Edge: The Beartooth Mountains And The Stillwater Complex

Yellowstone volcanism has produced some of the youngest rocks in North America. This same region also features some of the most ancient rocks in North America—as old as 3.96 billion years in the Beartooth Mountains to the northeast of Yellowstone caldera.
- By Kurt Repanshek - April 8th, 2025 2:30am