Yellowstone Supervolcano Mantle Extends All the Way to California and Oregon, Scientist Claims

The mantle rock that feeds Yellowstone supervolcano extends all the way to California and Oregon, a scientist has claimed. Victor Camp, a geologist from San Diego State University found there are "finger-like conduits" of mantle that extend westwards, providing magma to distant sites including the volcanic fields of Newberry and Medicine Lake.

Camp also said the mantle rock that sits beneath Yellowstone today appears to have come from the core-mantle boundary that sits deep beneath present-day San Diego. His findings are published in the journal Geology.

Earth is made up of three main layers—the crust, which is the thinnest layer, the mantle, which extends from 62 miles under the surface all the way down to over 1,600 miles, and finally the core. The mantle is made of hot molten rock.

Mantle plumes rise up because they are hotter and lower-density than the surrounding rock. The plume feeding Yellowstone rose up and met the base of the North American tectonic plate, where it was blocked. At this point, the plume melted and started spreading west.

By using seismic tomography images, coupled with data on the volcanic rock at the surface and chemistry, Camp was able to then trace this rock. He found that over millions of years, it spread out through narrow channels, splitting into new branches as it left Yellowstone and again as it got to the border of California and Oregon.

Yellowstone's Grand Prismatic Spring. iStock

Camp suggests that over the last two million years, the mantle rock that travels along these routes were responsible for eruptions at the Craters of the Moon lava flow field in Idaho. These conduits end at the Medicine Lake volcano in California and Newberry Volcano in Oregon.

"These channels have allowed low-density mantle to accumulate against the Cascades arc, thus providing a heated mantle source for mafic magmatism in the Newberry (Oregon) and Medicine Lake (California) volcanic fields," the study concludes.

Camp said the findings can help scientists better understand how mantle rock moves around deep beneath the surface of supervolcanoes. "Since the plume is not controlled by plate tectonics, it can rise and emerge anywhere on earth, depending on where it manages to break through the earth's surface," he said in a statement. "So, knowing this will help us understand supereruptions that have occurred before, and those that will occur in the future."

Not everyone is convinced of Camp's findings, however. Volcanologist Rebecca Williams, from the U.K.'s University of Hull, said the idea that volcanism in Central Oregon is linked to the Yellowstone-Snake River Plane is not new. "There is much scientific discussion around the YSRP plume, its migration and its relation to broader volcanism in the region," she told Newsweek.

She said the study presents no new data to support the idea that recent volcanism in the Newberry and Medicine Lake volcanic fields is the result of mantle flowing through channels—instead, the study uses models and data already in the literature. "It's a useful discussion, bringing the evidence together in this way, that will be a contribution to the ongoing debate of the relationship of the Cascadia Subduction Zone and the Yellowstone Hotspot and the multitude of volcanism in the Western U.S. Without new data, how much it ignites this discussion remains to be seen," she said.

Michael Poland, Scientist-in-Charge at Yellowstone Volcano Observatory, told Newsweek: "It's a nice model which puts together a lot of observations. It doesn't have an implications for Yellowstone specifically, but it offers more information about the Yellowstone hotspot system as a whole, since that system is not as straightforward as other hotspots, like Hawaii."

Correction 8/08, 2.45 a.m. The original article said Craters of the Moon is in Oregon. This has been changed to Idaho.

This article has been updated to include quotes from Michael Poland.