The Yellowstone Supervolcano –“Evidence of a Vast Magma Plume Discovered Stretching from Mexico”

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The Yellowstone supervolcano last erupted around 630,000 years ago, and scientists believe such eruptions were triggered by the influx of new magma into its large chamber. However, where previously scientists thought that process took place over thousands of years, recent evidence suggests the time scale is actually more like a few decades, according to the New York Times.


This week, a pair of geoscience researchers from the University of Texas using seismic data obtained from EarthScope's USArray, a project that placed geologic listening stations across North America, have discovered evidence of a plume of magma beneath Yellowstone National Park that is part of a zone that runs to the park all the way from Mexico. The plume is a still theoretical abnormality that lies at the boundary between the Earth's core and the mantle, and rises through the mantle into the crust—an abnormality that would exist as a vertical stream of magma.

 

The existence of a plume beneath Yellowstone has been hotly debated with some scientists suggesting a plume would explain the source of the heat that drives so much surface activity in Yellowstone. Others contest this saying it could be explained by shallow subduction or lithospheric processes.

In their paper published in Nature Geoscience today, researchers Peter Nelson and Stephen Grand, Carleton Professor of Geophysics, from the Jackson School of Geosciences at the University of Texas at Austin propose that Yellowstone’s heat source could come from a plume extending from the core-mantle boundary (CMB). Further, this potential plume could be situated in a zone of material that runs from Mexico all the way to the park.

According to a Nature press release, looking at a continental scale, the pair identified “a long, thin, sloping zone within the mantle through which seismic waves travel more slowly—and which may indicate the presence of unusually warm material.”

The image below is a depth cross-section through the plume structure showing its connection with the Yellowstone hotspot. (Nature Geoscience (2018) doi:10.1038/s41561-018-0075-y)

According to research from the University of Utah, that magma feeds into a pair of reservoir below Yellowstone’s surface, brimming with enough material to fill the Grand Canyon of Arizona nearly 14 times over.

Part of the reason this theory has been so contested when it comes to Yellowstone, according to Nelson and Grand, is that Yellowstone “has features not in accord with classical plume theory.” For instance, Yellowstone has more than one hotspot track. Then there’s the matter of the rock surrounding this plume. 

The Daily Galaxy via Nature and  and Yellowstone Insider

 

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