YELLOWSTONE NATIONAL PARK — A recent installment of the Caldera Chronicles from the Yellowstone Volcano Observatory explores the volcanic eruptions in Yellowstone National Park (YNP) and whether they’re linked to the retreat, or deglaciation, of glaciers.
Research hydrologist with the U.S. Geological Survey (USGS) Shaul Hurwitz explores the possibility in the article.
Scientists compared the time periods of YNP volcanic eruptions with evidence collected through radiometric dating, luminescence dating and records from “deep-sea sediment cores and ancient ice cores,” and found that there isn’t much evidence to suggest that major eruptions coincided with deglaciation.
There are two well-documented glacial periods in Yellowstone: the Bull Lake glacial period (which occurred 150,000 – 140,000 years ago) and the Pinedale glaciation period (which lasted from 22,000 to about 14,000 years ago). Before Bull Lake, scientists do not know of any other glaciations in Yellowstone, “likely because any evidence is buried under thick lava and ash flows.”
Hurwitz goes on to explain that the data suggests deglaciation periods are not correlated with volcanism, since the Bull Lake glacial period is relatively precise.
While the retreat of glaciers doesn’t appear to have triggered volcanic eruptions, there was some volcanic activity within 1,000 years of an ice sheet disappearing. “As the saying goes, however, ‘correlation does not imply causation,'” Hurwitz says in the article. “Just because two things are related in time doesn’t mean one causes the other.”
Researchers do believe, however, that the loss of the massive ice load may have reduced pressure on Yellowstone’s hydrothermal system, allowing groundwater to boil more readily and increasing the likelihood of explosive steam-driven events.
The findings in Yellowstone are different from findings in Iceland, where scientists have found evidence that deglaciation contributed to an increase in volcanic eruptions by reducing pressure on the crust and promoting magma generation.
For Yellowstone, however, the evidence indicates that melting glaciers were more likely to influence its hydrothermal system — so hot water, steam, and underground plumbing — than its volcanic activity.
