Researchers have discovered two ancient supereruptions associatedwith the Yellowstone hot spot track.
According to Science Alert,the two new-found events have been named the McMullen Creek eruption (occurringabout 8.99 million years ago) and the Grey's Landing eruption (occurring about8.72 million years ago).
They significantly adjust Yellowstone's long-term volcanictimeline and appear to show that huge eruptions are now occurring way lessfrequently than they once did.
The research, published earlier this month in the journalGeology, points out two new eruptions that emanated from the Yellowstonesupervolcano over the past 9 million years, including one experts believe isthe "volcanic province¡¯s largest and most cataclysmic event." The newdiscoveries suggest the intensity of the hotspot is waning drastically.
¡°It therefore seems that the Yellowstone hotspot hasexperienced a three-fold decrease in its capacity to produce super-eruptionevents,¡± said the study's lead study author, Thomas Knott, in a statement.¡°This is a very significant decline.¡±
Scientists were able to use a combination of chemical,magnetic, and radio-isotopic analysis to link volcanic deposits across tens ofthousands of square kilometres (or several thousand square miles), joiningtogether geological records that were previously treated as separate.
The first supereruption, known as the McMullen Creeksupereruption impacted a nearly 4,600-square-mile stretch of modern-day Idahoand the second, known as the Grey¡¯s Landing supereruption, impacted nearly8,900 square miles of Idaho and Nevada.
The supereruptions released clouds of searing hot gas andash at temperatures greater than 900 Celsius that spread at supersonic speed,sterilizing the land surface, according to Thomas Knott, a volcanologist at the The University of Leicester and the paper¡¯s lead author.
The Yellowstone supervolcano has erupted at least 10 timesover the past 16 million years, according to Live Science.
With the additional two supereruptions, there are now sixthat have occurred between 23 million and 5.3 million years ago, with onehappening on average every 500,000 years, according to the researchers. The twosupereruptions that have occurred since then averaged a span of one every 1.5million years, indicating a decline.
Knott said this new data raises questions about the lifespanof volcanic hot spots, wondering whether hotspots hit a "midlifecrisis" where activity slowly dwindles before their death.
Researchers won't know definitively until the hot spot dies,although Knott said it's almost impossible to predict when that may occur,state reports.