Global Volcanism Program | Image GVP-03348
The Mesa Falls Tuff is exposed in a quarry wall near Ashton, Idaho that shows light-colored airfall and pyroclastic-surge deposits overlain by orange-colored pyroclastic-flow deposits. The 280 cu km Mesa Falls Tuff, deposited about 1.3 million years ago during the second of Yellowstone's three largest eruptions, resulted in the formation of the 16-km-wide Henrys Fork caldera west of Yellowstone National Park.
Photo by Lee Siebert, 1994 (Smithsonian Institution).
This image is made available under the Public Domain Dedication CC0 license, but proper attribution is appreciated.