University of Texas researchers found evidence of a cloud beneath Yellowstone National Park. Published in the journal Nature Geoscience, the paper suggests that the plume is part of a zone that leads all the way from Mexico to Yellowstone.
Essentially, the existence of a cloud is a theoretical anomaly located between the Earth's core and the mantle and rises through the mantle into the crust. This would manifest as a vertical stream of magma, and the presence of such a cloud in Yellowstone National Park was hotly debated.
The existence of a cloud in the National Park would suggest an explanation for the amount of surface activity in the park – providing a heat source that acts as a catalyst for this explosion of action. However, other scientists have suggested that it could be explained in other ways, such as shallow subduction or lithospheric processes. Researchers Stephen Grand and Peter Nelson attempted to answer in one way or another, using a new approach to investigate the hotspot near Yellowstone National Park.
The study used seismic data obtained from the EarthScope USArray – a previous project in which geological equipment was placed at various locations throughout America. By using this existing infrastructure, Grand and Nelson were able to determine if there was actually a cloud or if any of the other explanations were more feasible.
After studying the data from the EarthScope USArray, the researchers found "a long, thin, sloping zone" about 72 by 55 kilometers inside the mantle. In this thin zone there were seismic waves that moved slower than the surrounding areas – an occurrence suggesting that the area would be warmer by 600-800 ° C. This warmer area indicates that there is actually a cloud below the surface of Yellowstone National Park.
This result is significant because it finally explains why there is just as much volcanic activity in Yellowstone. The existence of a cloud extending from the core-cladding boundary into the crust would provide the energy needed to produce the large amount of activity from the recorded history area.
The researchers recognize that more research is needed to determine why Yellowstone can exist at its current location exactly. They hypothesize, however, that it is possible "because the flag is kept stable by a portion of the Pacific Great Province at low shear rate."
Grand and Nelson have also claimed that the methods used by other researchers are in order. A study of a plume might be due to the global tomography and its inability to find thin thermal plumes, as they suspect, below Yellowstone, not suffice.
While this research is not necessarily a guarantee or complete explanation for the existence of volcanic yellowstone, there seems to be some skepticism regarding the existence of a plume. With more research we could learn more about the ancient origins of this natural phenomenon.