Samples of Lava Creek Tuff (Yellowstone caldera) with quartz and sanidine crystals indicated
Detailed Description
Samples of Lava Creek Tuff, which erupted during the formation of Yellowstone Caldera about 631,000 years ago, with large quartz and sanidine crystals circled in red. Photos by Faith Nolander, July 22, 2025.
Sources/Usage
Public Domain.