Comparison of the three ash-flow tuffs of the Yellowstone Group and resulting calderas


Comparison of the three ash-flow tuffs of the Yellowstone Group and resulting calderas

Caldera-forming ash-flow tuff Age (millions of years) Volume erupted (km3) Area covered (km2) Caldera dimensions (km) Caldera name
Lava Creek Tuff - 0.640 1,000 7,500 85 x 45 Yellowstone caldera
Mesa Falls Tuff  -1.3 280 2,700 16 km in diameter Henry's Fork caldera
Huckleberry Ridge Tuff  -2.1 2,450 15,500 75-95 x 40-601 Big Bend Ridge, Snake River, and Red Mountains caldera segments

1Inferred first-cycle caldera boundary is irregular; caldera consists of three overlapping collapse areas.


Rim of the Yellowstone caldera (the youngest caldera)

Aerial view of the NW rim of Yellowstone Caldera, Yellowstone National Park, Wyoming

Photograph courtesy of Bob Smith, University of Utah
 Aerial view of the striking NW rim of the Yellowstone caldera and intracaldera rhyolite lava flows at Madison Junction in Yellowstone National Park. View is looking north. The steep-facing caldera wall, 500 m tall, formed when the area in the foreground collapsed during eruption of the Lava Creek Tuff 640,000 years ago. The thick West Yellowstone rhyolite lava flow erupted about 110,000 years ago, and the Nez Perce Creek flow erupted 160,000 years ago.
 
Aerial photo of Mirror Lake and faults associated with NE rim of Yellowstone caldera
Faults associated with
the NE margin of Yellowstone caldera

Photograph of NE caldera rim fault scarp near Mirror Lake, Yellowstone National Park
Outermost fault associated with the NE
margin of the Yellowstone caldera

These views of faults outside the caldera rim illustrate that faults related to regional tectonic stresses can be associated with caldera collapse along a zone of concentric ring faults. Click on images for a description and larger-sized images.

Photographs courtesy of Bob Smith, University of Utah