January 21, 2008

Buried Volcano Discovered in Antarctica

A volcano beneath Antarctica’s icy surface has been detected
for the first time.

Under the frozen continent's western-most ice sheet, the
volcano erupted about 2,300 years ago yet remains active, according to a study
published Sunday in an online issue of the journal Nature Geosciences.

"We believe this was the biggest eruption
in Antarctica during the last 10,000 years," said study co-author Hugh
Corr, a glaciologist for the British Antarctic Survey (BAS). "It blew a
substantial hole in the ice sheet, and generated a plume of ash and gas that
rose around 12 kilometers (7.5 miles) into [the] air."

Brooding giant

Although ice buried the unnamed volcano, molten rock is
still churning below. David Vaughan, a glaciologist with the BAS and a
co-author of the new study, said the discovery might explain the speeding up of
historically slow-moving glaciers in the region.

“This eruption occurred close to Pine Island Glacier on the
West Antarctic Ice Sheet," Vaughan said. "The flow of this glacier
towards the coast has speeded up in recent decades, and it may be possible that
heat from the volcano has caused some of that acceleration."

The effect is similar to a person gliding down a Slip 'n
Slide: Volcanically melted
water beneath
the colossal ice sheet lubricates its movement, assisting its
gravity-powered journey toward the Antarctic Ocean.

Vaughan noted, however, that the hidden volcano doesn't explain widespread
thinning of Antarctic glaciers.

"This wider change most probably has its origin in
warming ocean waters," he said, which most scientists attribute to global
warming resulting from human activity, such as the use of fossil fuels.

Hide and seek

Corr and Vaughan used ice-penetrating radar to locate the
volcano just west of the expansive Pine Island Glacier. Specifically, they
detected a New Jersey-sized plot of ash at more than 8,000 square miles (20,700
square kilometers) beneath the ice.

The debris is a hallmark of an ancient eruption.

“The discovery of a ‘subglacial’ volcanic eruption from
beneath the Antarctic ice
sheet is unique in itself," Corr said. "But our techniques also allow
us to put a date on the eruption, determine how powerful it was and map out the
area where ash fell."

Scientists like Corr have used radar and other technologies
to find other features, such as lakes, tucked beneath the Antarctic ice.
Researchers also think that magma-heated rock beneath Greenland's massive ice
sheet is accelerating its melting, but whether a volcano or just a pool of
magma is responsible is still a matter of debate.