The Mesa Falls Tuff is a tuff

Tuff

Tuff is a type of rock consisting of consolidated volcanic ash ejected from vents during a volcanic eruption. Tuff is sometimes called tufa, particularly when used as construction material, although tufa also refers to a quite different rock. Rock that contains greater than 50% tuff is considered...

 formation created by the Mesa Falls eruption that formed the Henry's Fork Caldera

Henry's Fork Caldera

The Henry's Fork Caldera in Idaho is a caldera located an area known as Island Park west of Yellowstone National Park. The caldera was formed by one of the world's supervolcanos in an eruption of more than 280 cubic kilometers 1.3 million years BP, and is the source of the Mesa Falls Tuff.The...

 that is located in Idaho

Idaho

Idaho is a state in the Rocky Mountain area of the United States. The state's largest city and capital is Boise. Residents are called "Idahoans". Idaho was admitted to the Union on July 3, 1890, as the 43rd state....

 west of Yellowstone Park. It is the second most recent caldera forming eruption from the Yellowstone hotspot

Yellowstone hotspot

The Yellowstone hotspot, also referred to as the Snake River Plain-Yellowstone hotspot, is a volcanic hotspot responsible for large scale volcanism in Oregon, Nevada, Idaho, and Wyoming, United States. It created the eastern Snake River Plain through a succession of caldera forming eruptions...

 and ejected of 280 km³ of material. This eruption, 1.3 million years BP

Before Present

Before Present years is a time scale used in archaeology, geology, and other scientific disciplines to specify when events in the past occurred. Because the "present" time changes, standard practice is to use AD 1950 as the origin of the age scale, reflecting the fact that radiocarbon...

, was preceded by the Huckleberry Ridge Tuff

Huckleberry Ridge Tuff

The Huckleberry Ridge Tuff is a tuff formation created by the Huckleberry Ridge eruption that formed the Island Park Caldera that lies partially in Yellowstone Park, Wyoming and stretches westward into Idaho into a region known as Island Park...

 and succeeded by the Lava Creek Tuff

Lava Creek Tuff

Lava Creek Tuff is a tuff formation, in Wyoming, created when the Yellowstone Caldera erupted about 640,000 years ago.The Lava Creek Tuff distributed in a radial pattern around the caldera and is formed of of ash in pyroclastic flows....

 both of which were created by the Yellowstone hotspot

Yellowstone hotspot

The Yellowstone hotspot, also referred to as the Snake River Plain-Yellowstone hotspot, is a volcanic hotspot responsible for large scale volcanism in Oregon, Nevada, Idaho, and Wyoming, United States. It created the eastern Snake River Plain through a succession of caldera forming eruptions...

.