Exposure of rhyolite volcanic rocks in the central Snake River Plain
By Yellowstone Volcano Observatory
May 2004 (approx.)
Detailed Description
Exposure of rhyolite volcanic rocks in the central Snake River Plain showing a thick sequence of 10-12 million-year-old, densely welded, pyroclastic density flow units (darker units from middle of photo to top of hill) overlying a thick sequence of white, friable, ash fall deposits. USGS Photo by L. A. Morgan (May 2004).
Sources/Usage
Public Domain.