Mount Sidley West Antarctica: Volcano discovered smoldering under a kilometer of ice

Mount Sidley, at the leading edge of the Executive Committee Range in Marie Byrd Land is the last volcano in the chain that rises above the surface of the ice. 

But a group of seismologists has detected new volcanic activity under the ice about 30 miles ahead of Mount Sidley in the direction of the range's migration. 

The new finding suggests that the source of magma is moving beyond the chain beneath the crust and the Antarctic Ice Sheet. 

Credit: Doug Wiens

It wasn't what they were looking for but that only made the discovery all the more exciting.

In January 2010 a team of scientists had set up two crossing lines of seismographs across Marie Byrd Land in West Antarctica.

It was the first time the scientists had deployed many instruments in the interior of the continent that could operate year-round even in the coldest parts of Antarctica.

Like a giant CT machine, the seismograph array used disturbances created by distant earthquakes to make images of the ice and rock deep within West Antarctica. There were big questions to be asked and answered.

The goal, says Doug Wiens, professor of earth and planetary science at Washington University in St. Louis and one of the project's principle investigators, was essentially to weigh the ice sheet to help reconstruct Antarctica's climate history.

But to do this accurately the scientists had to know how the earth's mantle would respond to an ice burden, and that depended on whether it was hot and fluid or cool and viscous.

The seismic data would allow them to map the mantle's properties.

In the meantime, automated-event-detection software was put to work to comb the data for anything unusual.

When it found two bursts of seismic events between January 2010 and March 2011, Wiens' PhD student Amanda Lough looked more closely to see what was rattling the continent's bones.

Was it rock grinding on rock, ice groaning over ice, or, perhaps, hot gases and liquid rock forcing their way through cracks in a volcanic complex?

Uncertain at first, the more Lough and her colleagues looked, the more convinced they became that a new volcano was forming a kilometer beneath the ice.

The discovery of the new as yet unnamed volcano is announced in the Nov. 17 advanced online issue of Nature Geoscience.

Read the full article here in www.phys.org