Yellowstone hotspot
Volcanic hotspot underlying the North American tectonic plate.
The Yellowstone hotspot is a volcanic hotspot in the United States that has driven major volcanic activity across Idaho, Montana, Nevada, Oregon, and Wyoming. This activity occurred as the North American tectonic plate drifted over the hotspot. Over time, a series of caldera-forming eruptions shaped the eastern Snake River Plain. The calderas created include the Island Park Caldera, Henry's Fork Caldera, and the Bruneau-Jarbidge caldera. Today, the hotspot sits beneath the Yellowstone Caldera. Its most recent supereruption, the Lava Creek Eruption, happened 640,000 years ago, producing the Lava Creek Tuff and forming the current Yellowstone Caldera. The Yellowstone hotspot is one of the few volcanic hotspots under the North American plate; another is the Anahim hotspot.
The eastern Snake River Plain is a low-lying area that cuts across Basin and Range mountain structures, running roughly parallel to the plate's movement. Beneath younger basalt flows lie rhyolite lavas and ignimbrites that erupted as the lithosphere passed over the hotspot. In some places, younger volcanoes that formed after the hotspot had moved on covered the plain with fresh basalt lava, such as at Craters of the Moon National Monument and Preserve. The central Snake River Plain is similar but contains thick layers of lake and stream sediments, including those at the Hagerman Fossil Beds.
On the Nevada–Oregon border, the McDermitt volcanic field is often cited as the hotspot's first impact point, but newer dating and mapping show that the mid-Miocene volcanism affected a much larger area. Three newly identified silicic calderas in northwest Nevada, along with the Virgin Valley Caldera and McDermitt Caldera, formed during a brief period 16.5 to 15.5 million years ago, near the end of the Steens flood basalt eruptions. These northwest Nevada calderas range from 15 to 26 km across and deposited high-temperature rhyolite ignimbrites over roughly 5,000 square kilometers. As the hotspot moved beneath Nevada and Oregon, it increased ecological beta diversity by breaking up previously connected habitats and adding topographic variety to western North America.
The Bruneau-Jarbidge volcanic field erupted between ten and twelve million years ago, spreading a thick ash layer and forming a wide caldera. Within a hundred miles, animals were suffocated and burned by pyroclastic flows. Farther away, in
- type
- Volcanic hotspot
- location
- United States (Idaho, Montana, Nevada, Oregon, Wyoming)
- most_recent_supereruption
- Lava Creek Eruption, 640,000 years ago
- associated_calderas
- Island Park Caldera, Henry's Fork Caldera, Bruneau-Jarbidge caldera, Yellowstone Caldera
- known_for
- Large scale volcanism and caldera-forming supereruptions
Lore & Background
The Yellowstone hotspot formed the eastern Snake River Plain as the North American plate moved over it. Its calderas include the Island Park Caldera, Henry's Fork Caldera, and Bruneau-Jarbidge caldera. The hotspot currently lies under the Yellowstone Caldera, which formed 640,000 years ago from the Lava Creek Eruption.
In Nevada and Oregon, three silicic calderas were newly identified west of the McDermitt volcanic field, along with the Virgin Valley Caldera, formed 16.5–15.5 million years ago. The Bruneau-Jarbidge volcanic field erupted between ten and twelve million years ago, spreading ash as far as Ashfall Fossil Beds in Nebraska.
The Heise volcanic field produced four large-volume rhyolitic eruptions from 6.6 million years ago, ending with the Kilgore Tuff 4.5 million years ago. The Yellowstone Plateau volcanic field includes four adjacent calderas, with the Henry's Fork Caldera formed 1.3 million years ago.
Reader's Guide
The Yellowstone hotspot is significant for its role in shaping the landscape of the western United States through repeated caldera-forming supereruptions. Its eruptions produced vast ash deposits, such as the Huckleberry Ridge Tuff found from southern California to the Mississippi River, and the Lava Creek Tuff. The hotspot's activity has created the eastern Snake River Plain and influenced ecological beta diversity by fragmenting habitats and increasing topographic diversity.
The hotspot's eruptive history includes both explosive caldera-forming events and non-explosive lava flows, with the most recent lava flow about 70,000 years ago. The appearance of 'light' oxygen isotope magmas at Heise and Yellowstone may indicate that the continental crust above the mantle plume is becoming exhausted, potentially signaling the waning of the hotspot. A 2020 study suggests the hotspot may be waning, and it could be another 1–2 million years before a new supervolcano forms to the northeast.
Did You Know?
- The Yellowstone hotspot is one of a few volcanic hotspots underlying the North American tectonic plate; another example is the Anahim hotspot.
- The Bruneau-Jarbidge event deposited a foot of ash at Ashfall Fossil Beds in Nebraska, 1000 miles downwind.
- The Henry's Fork Caldera is the only one of the hotspot's calderas that is currently clearly visible.
- The Island Park Caldera supereruption 2.1 million years ago produced 2500 km³ of ash.
More in Structural Geology And Tectonics 1-24
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