Thursday, December 12, 2013

20 Ancient Supervolcanoes Discovered in Utah and Nevada

via Sci-News
http://www.sci-news.com

Geologists from Brigham Young University, Berkeley Geochronology Center and the Pacific Northwest National Laboratory have found evidence of twenty ancient supervolcanoes near the Utah-Nevada border.




Supervolcanoes are giant volcanoes that blast out more than 1,000 cubic km of volcanic material when they erupt. They are different from the more familiar straddle volcanoes because they aren’t as obvious to the naked eye and affect enormous areas.

“Supervolcanoes as we’ve seen are some of Earth’s largest volcanic edifices, and yet they don’t stand as high cones. At the heart of a supervolcano instead, is a large collapse. Those collapses in supervolcanoes occur with the eruption and form enormous holes in the ground in plateaus, known as calderas,” said Dr Eric Christiansen of Brigham Young University, who is a co-author of two papers published in the journal Geosphere (paper 1 & paper 2).

The newly discovered supervolcanoes aren’t active today, but 30 million years ago more than 5,500 cubic km of magma erupted during a one-week period near a place called Wah Wah Springs.

“In southern Utah, deposits from this single eruption are 4 km thick. Imagine the devastation – it would have been catastrophic to anything living within hundreds of miles,” Dr Christiansen said.


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