The Yellowstone hotspot is a volcanic hotspot in the United States responsible for large scale volcanism in Idaho, Montana, Nevada, Oregon, and Wyoming, formed as the North American tectonic plate moved over it. It formed the eastern Snake River Plain through a succession of caldera-forming eruptions. The resulting calderas include the Island Park Caldera, Henry's Fork Caldera, and the Bruneau-Jarbidge caldera. The hotspot currently lies under the Yellowstone Caldera. The hotspot's most recent caldera-forming supereruption, known as the Lava Creek Eruption, took place 640,000 years ago and created the Lava Creek Tuff, and the most recent Yellowstone Caldera. The Yellowstone hotspot is one of a few volcanic hotspots underlying the North American tectonic plate; another example is the Anahim hotspot.

Snake River Plain

The eastern Snake River Plain is a topographic depression that cuts across Basin and Range Mountain structures, more or less parallel to North American Plate motion. Beneath more recent basalts are rhyolite lavas and ignimbrites that erupted as the lithosphere passed over the hotspot. Younger volcanoes that erupted after passing over the hotspot covered the plain with young basalt lava flows in places, including Craters of the Moon National Monument and Preserve.

The central Snake River plain is similar to the eastern plain, but differs by having thick sections of interbedded lacustrine (lake) and fluvial (stream) sediments, including the Hagerman Fossil Beds.

Nevada–Oregon calderas

Although the McDermitt volcanic field on the Nevada–Oregon border is frequently shown as the site of the initial impingement of the Yellowstone Hotspot, new geochronology and mapping demonstrates that the area affected by this mid-Miocene volcanism is significantly larger than previously appreciated. Three silicic calderas have been newly identified in northwest Nevada, west of the McDermitt volcanic field as well as the Virgin Valley Caldera. These calderas, along with the Virgin Valley Caldera and McDermitt Caldera, are interpreted to have formed during a short interval 16.5–15.5 million years ago, in the waning stage of the Steens flood basalt volcanism. The northwest Nevada calderas have diameters ranging from 15 to 26&nbsp;km and deposited high temperature rhyolite ignimbrites over approximately 5000&nbsp;km<sup>2</sup>.

As the hotspot drifted beneath what is now Nevada and Oregon, it increased ecological beta diversity locally by fragmenting previously connected habitats and increasing topographic diversity in western North America.

The Bruneau-Jarbidge volcanic field erupted between ten and twelve million years ago, spreading a thick blanket of ash in the Bruneau-Jarbidge event and forming a wide caldera. Animals were suffocated and burned in pyroclastic flows within a hundred miles of the event, and died of slow suffocation and starvation much farther away, notably at Ashfall Fossil Beds, located 1000 miles downwind in northeastern Nebraska, where a foot of ash was deposited. There, two hundred fossilized rhinoceros and many other animals were preserved in two meters of volcanic ash. By its characteristic chemical fingerprint and the distinctive size and shape of its crystals and glass shards, the volcano stands out among dozens of prominent ashfall horizons laid down in the Cretaceous, Paleogene, and Neogene periods of central North America. The event responsible for this fall of volcanic ash was identified as Bruneau-Jarbidge. Prevailing westerlies deposited distal ashfall over a vast area of the Great Plains.

Volcanic fields

Twin Falls and Picabo volcanic fields

The Twin Falls and Picabo volcanic fields were active about 10 million years ago. The Picabo Caldera was notable for producing the Arbon Valley Tuff 10.2 million years ago.

Heise volcanic field

The Heise volcanic field of eastern Idaho produced explosive caldera-forming eruptions which began 6.6 million years ago and lasted for more than 2 million years, sequentially producing four large-volume rhyolitic eruptions. The first three caldera-forming rhyolites – Blacktail Tuff, Walcott Tuff and Conant Creek Tuff – totaled at least 2250&nbsp;km<sup>3</sup> of erupted magma. The final, extremely voluminous, caldera-forming eruption – the Kilgore Tuff – which erupted 1800&nbsp;km<sup>3</sup> of ash, occurred 4.5 million years ago.

Yellowstone Plateau

thumb|upright=1.5|Yellowstone sits on top of four overlapping calderas.

The Yellowstone Plateau volcanic field is composed of four adjacent calderas. West Thumb Lake is itself formed by a smaller caldera which erupted 174,000 years ago. (See Yellowstone Caldera map.) The Henry's Fork Caldera in Idaho was formed in an eruption of more than 1.3 million years ago, and is the source of the Mesa Falls Tuff.

A 2020 study suggests that the hotspot may be waning.

Eruptive history

thumb|upright=1.35|Number of earthquakes in [[Yellowstone National Park region (1973–2014)]]

thumb|upright=1.35|Map of recent Yellowstone eruption fields, in comparison with a recent [[Long Valley Caldera eruption and Mount St. Helens.]]

  • Wapi Lava field and King's Bowl blowout, northeast of Rupert, Idaho; 2.270&nbsp;ka ±0.15. (2,270 years ago)
  • Hell's Half Acre lava field, west to southwest of Idaho Falls; 3.250&nbsp;ka ±0.15. (3,250 years ago)
  • Shoshone lava field, North of Twin Falls, Idaho; 8.400&nbsp;ka ±0.3.
  • Craters of the Moon National Monument and Preserve; Great Rift of Idaho; the lava field was formed during eight eruptive episodes between about 15 and 2&nbsp;ka.
  • Kings Bowl and Wapi lava fields formed about 2.250&nbsp;ka.
  • Yellowstone Caldera; between 70 and 150&nbsp;ka; intracaldera rhyolitic lava flows.
  • Henry's Fork Caldera (size: 16&nbsp;km wide); 1.3&nbsp;Ma; VEI&nbsp;7; of Mesa Falls Tuff.
  • Heise volcanic field, Idaho:
  • Kilgore Caldera (size: 80 x 60&nbsp;km); VEI&nbsp;8; of Kilgore Tuff; 4.45&nbsp;Ma ±0.05.
  • 8.75&nbsp;Ma tuff of Lost River Sinks
  • Picabo volcanic field, Picabo, Idaho; 10.09&nbsp;Ma (Arbon Valley Tuff A) and 10.21&nbsp;Ma ±0.03 (Arbon Valley Tuff B).
  • Trout Creek Mountains, East of the Pueblo Mountains, Whitehorse Caldera (size: 15&nbsp;km wide), Oregon; 15&nbsp;Ma; of Whitehorse Creek Tuff.
  • Jordan Meadow Caldera, (size: 10–15&nbsp;km wide); 15.6&nbsp;Ma; Longridge Tuff member 2–3.
  • Yellowstone hotspot (?), Lake Owyhee volcanic field; 15.0 to 15.5&nbsp;Ma.
  • Yellowstone hotspot (?), Northwest Nevada volcanic field, Virgin Valley, High Rock, Hog Ranch, and unnamed calderas; West of the Pine Forest Range, Nevada; 15.5 to 16.5&nbsp;Ma; Tuffs: Idaho Canyon, Ashdown, Summit Lake, and Soldier Meadow.
  • Columbia River Basalt Province: Yellowstone hotspot sets off a huge pulse of volcanic activity, the first eruptions were near the Oregon-Idaho-Washington border. Columbia River and Steens flood basalts, Pueblo, and Malheur Gorge-region, Pueblo Mountains, Steens Mountain, Washington, Oregon, and Idaho; most vigorous eruptions were from 14 to 17&nbsp;Ma; of lava.
  • Columbia River flood basalts,
  • Steens flood basalts,
  • Crescent volcanics, Olympic Peninsula/ southern Vancouver Island, 50–60&nbsp;Ma.
  • Siletz River Volcanics, Oregon Coast Range, a sequence of basaltic pillow lavas.
  • Carmacks Group, Yukon, , 70&nbsp;Ma.

Notes

  • Harney Basin (Devine Canyon Tuff), McDermitt volcanic field, Owyhee-Humboldt volcanic field, Lake Owyhee volcanic field (or Jordan Valley volcanic field, Lake Owyhee), Jordan Craters, Santa Rosa – Calico volcanic field, Hawkes Valley – Lone Mountain volcanic field, Northwest Nevada volcanic field, Juniper Mountain caldera complex, and Silver City – Delamar caldera complex (Silver City, Idaho) are nested in one area. Geologic landmarks of the area: Steens Mountain, Northern Nevada Rift, Midas Trough, Santa Rosa Mountains, Bull Run – Tuscarora Mountains, Owyhee Mountains, Oregon-Idaho Graben, and western Snake River Plain.
  • Other manifestations of the Yellowstone hotspot: Rexburg Volcanic Field (4.3&nbsp;Ma), West of Rexburg, Idaho; Henry's Lake Volcanism (1.3&nbsp;Ma), Henry's Lake; Blackfoot Volcanic Field (3&nbsp;Ma), Northwest of Soda Springs, Idaho; Gem Valley Volcanic Field (600 to 50&nbsp;ka), near Grace, Idaho.
  • The initial volcanism is part of the Basin and Range Province and the Oregon-Idaho graben (15.0 to 15.5&nbsp;Ma).

See also

  • Timeline of volcanism on Earth

Notes

References

Map references

Further reading

  • Yellowstone hotspot interactive
  • National Park Service interactive map showing trace of the hotspot over time
  • The Yellowstone magmatic system from the mantle plume to the upper crust (46,000 km3 magma reservoir below chamber)