Yellowstone Supervolcano Could Be Fueled By Churning Chunks of Pacific Ocean Plate, Not Mantle Plume

The Yellowstone supervolcano could be fueled by a faraway heat source off the Pacific Northwest coast—which challenges the hypothesis that the mantle plume beneath Yellowstone is responsible for volcanism at its surface. The recent findings, published in mid-December, however, don't point to any future super eruptions. Instead, the study helps scientists better understand the complex volcanic system that seems to have many concerned that a super eruption will occur. (Spoiler alert: That is very unlikely).

"The heat needed to drive volcanism usually occurs in areas where tectonic plates meet and one slab of crust slides, or subducts, under another," Lijun Liu, lead author and geology professor at University of Illinois at Urbana-Champaign, said in a statement. "However, Yellowstone and other volcanic areas of the inland western U.S. are far away from the active plate boundaries along the West Coast. In these inland cases, a deep-seated heat source known as a mantle plume is suspected of driving crustal melting and surface volcanism."

The study, published in Nature Geoscience, used seismic tomography to determine the geologic history behind the Yellowstonevolcanic system. Based on possible geologic histories of the past 20 million years in the western U.S., they found little support for the mantle plume hypothesis. Liu's and her team's findings point to the Pacific Ocean's plates as the supervolcano's heat source.

A broken-off piece of the ancient Farallon plate has been slowly sliding east beneath the western part of the U.S. beginning about 200 million years ago, reported ScienceNews. The ancient plate broke apart—and a slab of it slipped closer to Yellowstone. Researchers think that the tearing up of that plate's fragments could have led to outpourings of magma, keeping the heat in Yellowstone's volcanic system.

"A robust result from these models is that the heat source behind the extensive inland volcanism actually originated from the shallow oceanic mantle to the west of the Pacific Northwest coast," Liu said. "This directly challenges the traditional view that most of the heat came from the plume below Yellowstone."

One factor that made this study different was adding heat to their models. Hot materials like those in the mantle plume should rise towards the surface—but they found the mantle plume was sinking deeper into Earth. Liu said that it "seems counterintuitive," but that specific finding is what led the researchers to point their attention towards the Pacific Ocean. Future studies, said co-author and graduate student Quan Zhou, will add chemical data from volcanic rocks to the model.

"That will help us further constrain the source of the magma because rocks from deep mantle plumes and near-surface tectonic plates could have different chemistries," Zhou said in a statement.

While Liu's research untangles the mystery of Yellowstone a little bit more, researchers emphasized that this model doesn't predict specific future-eruptions. Fears of future eruptions have caused a flurry of concerns. As Newsweek previously reported, a misinterpreted New York Times article resulted in inaccurate and misleading news coverage following it, which added fuel to fire about the fears of a supereruption. The most recent eruption was 631,000 years ago. Though an eruption would blanket huge swaths of the U.S. in ash and change global climate, the chances of this happening remain exceedingly low.