Scientists discover supervolcanoes in Utah

Scientists have discovered supervolcanoes in southern Utah which caused some of the largest volcanic eruptions in Earth's history 30 million years ago.
These super-volcanoes hiding in plain sight aren't active now, but 30 million years ago more than 5,500 cubic kilometres of magma erupted during a one-week period near a place called Wah Wah Springs.
By comparison, this eruption was about 5,000 times larger than the 1980 Mount St Helens eruption, researchers said.
"In southern Utah, deposits from this single eruption are 13,000 feet thick," said Eric Christiansen, the lead author from the Brigham Young University.
"Imagine the devastation - it would have been catastrophic to anything living within hundreds of miles," said Christiansen.

Dinosaurs were already extinct during this time period, but what many people don't know is that 25-30 million years ago, North America was home to rhinos, camels, tortoises and even palm trees. Evidence of the ancient flora and fauna was preserved by volcanic deposits.

The research group, headed by Christiansen and professor Myron Best, measured the thickness of the pyroclastic flow deposits.
They used radiometric dating, X-ray fluorescence spectrometry, and chemical analysis of the minerals to verify that the volcanic ash was all from the same ancient super-eruption.
They found that the Wah Wah Springs eruption buried a vast region extending from central Utah to central Nevada and from Fillmore on the north to Cedar City on the south. They even found traces of ash as far away as Nebraska.

But this wasn't an isolated event; the geologists found evidence of fifteen super-eruptions and twenty large calderas.
Despite their enormous size, the super-volcanoes have been hidden in plain sight for millions of years.
"The ravages of erosion and later deformation have largely erased them from the landscape, but our careful work has revealed their details," said Christiansen.
Super-volcanoes are different from the more familiar "straddle" volcanoes - like Mount St Helens - because they are not as obvious to naked eye and they affect enormous areas.
The research was published in the journal Geosphere.