Antarctica's big secret: Active volcanic heat found under Pine Island Glacier

by Chris Ciaccia

 

View from the bow of the icebreaker the RRS James Clark Ross on a 2014 scientific expedition, during which University of Rhode Island researcher and five other scientists discovered an active volcanic heat source beneath the Pine Island Glacier in Antarctica.  (Brice Loose)

Researchers have made a shocking discovery under the Pine Island Glacier in Antarctica — an active volcanic heat source, which they say has played a "critical role" in the movement and melting of the glacier.

The scientists were looking at the role the ocean plays in causing glaciers to weaken when the discovery was made.

“We were looking to better understand the role of the ocean in melting the ice shelf,” Assistant Professor Brice Loose of Newport, R.I., a chemical oceanographer and lead author of the paper, said in a statement.

Loose added that the group was "sampling the water for five different noble gases, including helium and xenon," when the discovery was made.
“We weren’t looking for volcanism, we were using these gases to trace other actions,” Loose said. “When we first started seeing high concentrations of helium-3, we thought we had a cluster of bad or suspicious data.”

Loose said the presence of helium-3 is a "fingerprint for volcanism," noting it's relatively abundant in the seawater at the Pine Island shelf.

University of East Anglia Professor Karen Heywood, who also worked on the study, said the presence of volcanoes just means there's an additional source of heat to melt the ice.
"It will be important to include this in our efforts to estimate whether the Antarctic ice sheet might become unstable and further increase sea level rise," Heywood said.

Last year, significant parts of the Pine Island Glacier separated from the main shelf. In February 2017, a piece of the glacier approximately 1 mile wide separated. And in September 2017, a chunk of ice nearly four times the size of Manhattan separated from the Pine Island Glacier, according to LiveScience.

The amount of ice going into the ocean is staggering, measured in gigatons, Loose said. A gigaton is equal to 1 billion metric tons.

It's well understood that the West Antarctic Ice Sheet lies on top of a large or major volcanic rift system, but there has been no current magmatic activity, Loose noted. The last recorded activity was 2,200 years ago, but the volcanic heat discovered is new. Loose said it's impossible to measure the normal indicators of the volcanism, including heat and smoke, because the rift is so far below the ice.

Despite the discovery of the volcanic heat, the researchers noted that climate change is still the driving force for melting the ice, something other studies have repeatedly backed up, Loose said.
“Climate change is causing the bulk of glacial melt that we observe, and this newly discovered source of heat is having an as-yet undetermined effect, because we do not know how this heat is distributed beneath the ice sheet," Loose said.