Mammoth in Yellowstone National Park in Park County, Wyoming — The American West (Mountains)
Still Venting After All These Years
Photographed By Bill Coughlin, July 30, 2015
1. Still Venting After All These Years Marker
The Grand Canyon of the Yellowstone River slices through an ancient hydrothermal basin. The basin developed in rhyolitic lava and ash that flowed into the Yellowstone Caldera about 500,000 years ago. The river carved this spectacular canyon through the hardened lava (rhyolitic rock) and welded ash (tuff). Hot areas and steam vents still exist in the canyon. They allow heat, gases, and hot water to escape from the underground Yellowstone volcano.
Rhyolite Rust
On cool days, puffs of steam waft from vents near the bottom of the canyon. You might also see cinnamon-colored splotches on the canyon walls. The rust spots form when iron in the rhyolite is exposed to moisture and oxygen.
* The canyon is about 20 miles (32 km) long.
* Parts of the canyon are nearly 1,200 feet (366 m) deep.
* The canyon is forever growing longer, deeper, and wider.
* Water erosion, rather than glaciation, sculpted the canyon.
* Hydrothermal features are found along faults and fractures in the canyon wall.
Erected by National Park Service.
Topics. This historical marker is listed in this topic list: Natural Features.
Location. 44° 43.184′ N, 110° 29.734′ W. Marker is in Yellowstone National Park
this page online
Other nearby markers. At least 8 other markers are within walking distance of this marker. Brink of Lower Falls (about 500 feet away, measured in a direct line); Geologic Junction (approx. ¼ mile away); Uncle Tom’s Trail (approx. ¼ mile away); Uncle Tom’s Point (approx. 0.3 miles away); Waterfall Makers (approx. 0.4 miles away); Lookout Point (approx. 0.4 miles away); Upper Falls of the Yellowstone River (approx. 0.4 miles away); Brink of Upper Falls (approx. half a mile away). Touch for a list and map of all markers in Yellowstone National Park.
More about this marker. A photograph of the canyon appears on the left side of the marker.
Photographed By Bill Coughlin, July 30, 2015
2. Still Venting After All These Years Marker
Photographed By Bill Coughlin, July 30, 2015
3. Grand Canyon of the Yellowstone
Photographed By Bill Coughlin, July 30, 2015
4. Grand Canyon and Upper Falls
Photographed By Bill Coughlin, July 30, 2015
5. Yellowstone River in the Canyon
Credits. This page was last revised on February 16, 2023. It was originally submitted on September 24, 2015, by Bill Coughlin of Woodland Park, New Jersey. This page has been viewed 342 times since then and 13 times this year. Photos: 1, 2, 3, 4, 5. submitted on September 24, 2015, by Bill Coughlin of Woodland Park, New Jersey.
