It had been long believed that the source of Yellowstone’s eruptions came from heat deep in the Earth’s core which rose to the top to power explosions.
However, according to new research, the devastating eruptions were actually caused by a gigantic oceanic plate which broke into pieces tens of millions of years ago, unsettling the mantle beneath Yellowstone leading to some of the most violent lava explosions in the history of the world.
Experts created X-ray images of the layers beneath the Wyoming-based supervolcano and found a shattered oceanic plate at a depth of about 250 to 400 miles right beneath Yellowstone.
Lead author of the study Ying Zhou, an associate professor with the Virginia Tech College of Science’s Department of Geosciences, said: “In this research, there was no evidence of heat coming directly up from the Earth’s core to power the surface volcano at Yellowstone.
“Instead, the underground images we captured suggest that Yellowstone volcanoes were produced by a gigantic ancient oceanic plate that dove under the Western United States about 30 million years ago.
“This ancient oceanic plate broke into pieces, resulting in perturbations of unusual rocks in the mantle which led to volcanic eruptions in the past 16 million years.
“This evidence was in direct contradiction to the plume model.”
The team found that the Oceanic Farallon plate, which used to sit where the Pacific Ocean is now, had somehow forced itself beneath the western parts of the United States.
As the Farallon plate crumbled, it sunk even farther into the ground and pushing hot materials from the Earth’s core upwards to form what is now Yellowstone.
Ms Zhou said: “The process started at the Oregon-Idaho border about 16 million years ago and propagated northwestward, forming a line of volcanoes that are progressively younger as they stretched northwest to present-day Wyoming.
“If the North American plate was moving slowly over a position-fixed plume at Yellowstone, it will displace older volcanoes towards the Oregon-Idaho border and form a line of volcanoes, but such a deep plume has not been found.
“It has always been a problem there, and scientists have tried to come up with different ways to explain the cause of Yellowstone volcanoes, but it has been unsuccessful.”
Ms Zhou will now continue her study, saying: “The next step will be to increase the resolution of the X-ray-like images of the underground rock.
“More detailed images of the unusual rocks in the deep earth will allow us to use computer simulation to recreate the fragmentation of the gigantic oceanic plate and test different scenarios of how rock melting and magma feeding system work for the Yellowstone volcanoes.”