Yellowstone supervolcano is not powered magma from the Earth’s core

Lurking beneath Yellowstone National Park in Wyoming is a supervolcano capable of blasting rock and ash thousands of miles into the air.

Until now, experts believed the long-dormant supervolcano was created when a ballooning reservoir of magma burst through the crust of the planet.

Known as the plume model, this is how volcanoes are created around the world.

However, scientists have now confirmed Yellowstone was created when a gigantic ancient oceanic plate plunged under the west coast of the United States, more than 30 million years ago.

As it descended, the ancient plate splintered into thousands of pieces, forcing unusual rocks into the mantel, triggering a string of destructive volcanic eruptions.

Yellowstone is one of the most seismically active areas in the world and there are regular earthquakes detected in and around the supervolcano. 

 

This is the location of the Yellowstone’s hotspot track. The triangles indicate general locations of the Yellowstone volcanoes with ages shown in millions of years, plotted on a topography map of the Western United States

The latest findings were led by Ying Zhou, a theoretical seismologist from the Department of Geosciences at Virginia Tech College of Science in Blacksburg, Virginia.

Zhou and her team found no evidence of heat coming directly 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,’ she explained.

‘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.’

Dr Zhou, who has published her paper in Nature Geoscience, created X-ray-like images of the Earth’s deep interior using the USArray – a dense network of permanent and portable seismographs across the continental United States.

These seismographs record local, regional, and distant teleseismic earthquakes.

Dr Zhou discovered an anomalous underground structure at a depth of around 250 to 400 miles (400-650km) directly beneath the line of volcanoes.

For decades experts believed that the long-dormant supervolcano was powered by a reservoir of magma from the Earth's core. Pictured is Yellowstone National Park's Grand Prismatic Pool

For decades experts believed that the long-dormant supervolcano was powered by a reservoir of magma from the Earth’s core. Pictured is Yellowstone National Park’s Grand Prismatic Pool

Scientists led by theoretical seismologist Ying Zhou have now confirmed Yellowstone was created when a gigantic ancient oceanic plate plunged under the west coast of the United States, more than 30 million years ago

Scientists led by theoretical seismologist Ying Zhou have now confirmed Yellowstone was created when a gigantic ancient oceanic plate plunged under the west coast of the United States, more than 30 million years ago

‘This evidence was in direct contradiction to the plume model,’ Dr Zhou said.

The new images showed that the oceanic Farallon plate, once found where the Pacific Ocean is today, wedged itself beneath present-day western United States.

The ancient oceanic plate splintered, breaking into pieces and resulting in a section of the subducted oceanic plate tearing off and sinking down, deep into the planet.

As it sank, the section of oceanic plate slowly started to push hot materials upward, towards the surface, to form the volcanoes that now make up Yellowstone. 

The chain of volcanoes around Yellowstone have been slowly moving ever since.

It has now been revealed that Yellowstone was created by a gigantic ancient oceanic plate that dove under the US 30 million years ago

It has now been revealed that Yellowstone was created by a gigantic ancient oceanic plate that dove under the US 30 million years ago

‘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,’ Dr Zhou said.

The previously-held plume model had been used to explain the unique Yellowstone hotspot track. This refers to the line of volcanoes in Oregon, Idaho, and Wyoming, that pepper part of the Midwest.

‘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,’ Dr Zhou said.

This USGS graphic shows how a 'super eruption' of the molten lava under Yellowstone National Park would spread ash across the United States

This USGS graphic shows how a ‘super eruption’ of the molten lava under Yellowstone National Park would spread ash across the United States

COULD AN ERUPTION AT THE YELLOWSTONE SUPERVOLCANO BE PREVENTED?

Previous research found a relatively small magma chamber, known as the upper-crustal magma reservoir, beneath the surface

Recent research found a small magma chamber, known as the upper-crustal magma reservoir, beneath the surface

Nasa believes drilling up to six miles (10km) down into the supervolcano beneath Yellowstone National Park to pump in water at high pressure could cool it.

Despite the fact that the mission would cost $3.46 billion (£2.63 billion), Nasa considers it ‘the most viable solution.’ 

Using the heat as a resource also poses an opportunity to pay for plan – it could be used to create a geothermal plant, which generates electric power at extremely competitive prices of around $0.10 (£0.08) per kWh.

But this method of subduing a supervolcano has the potential to backfire and trigger the supervolcanic eruption Nasa is trying to prevent.

‘Drilling into the top of the magma chamber ‘would be very risky;’ however, carefully drilling from the lower sides could work. 

This USGS graphic shows how a 'super eruption' of the molten lava under Yellowstone National Park would spread ash across the United States

This USGS graphic shows how a ‘super eruption’ of the molten lava under Yellowstone National Park would spread ash across the United States

Even besides the potential devastating risks, the plan to cool Yellowstone with drilling is not simple.

Doing so would be an excruciatingly slow process that one happen at the rate of one metre a year, meaning it would take tens of thousands of years to cool it completely. 

And still, there wouldn’t be a guarantee it would be successful for at least hundreds or possibly thousands of years. 

‘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,’ she said, adding that hotspot tracks are more common in oceans, such as the Hawaii islands. 

The last Yellowstone eruption was about 630,000 years ago, according to experts.

When it last blew the supervolcano produced one of the largest known blasts on Earth, spewing more than 2,000 times as much ash as Mount St Helens did when it erupted in 1980, killing 57 people in the most disastrous eruption in US history.

Yellowstone is currently recharging as its magma chambers fill up with molten rock from the Earth’s mantle – the subsurface layer just beneath the crust.

Once these chambers fill the landform could explode at any time, potentially erupting within months or as far as several millennia after a magma recharge.

The eruption occurs when the magma chambers burst, throwing as much as 240 cubic miles (1,000 cubic kilometres) of magma into the air.

A key driver of the volcano’s destructive power is an explosive, silica-rich volcanic rock called rhyolite that break’s through the Earth’s crust during an eruption.

Dr Zhou and her colleagues have no new predictions for if – or when – Yellowstone could erupt again.

‘This is the first time the new imaging theory has been applied to this type of seismic data, which allowed us to see anomalous structures in the Earth’s mantle that would otherwise not be resolvable using traditional methods,’ Dr Zhou said.

‘The next step will be to increase the resolution of the X-ray-like images of the underground rock,’ she added.

‘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.’

 



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