An international team of researchers has discovered an active volcanic source underneath the Pine Island Glacier, located in western Antarctica. It was already known that the West Antarctic Ice Sheet (WAIS) sits over a major volcanic rift system, but actually finding the volcanoes has not been easy.
As reported in Nature Communications, the researchers were able to find the source thanks to chemical traces in the water that couldn’t have come from anywhere else. The discovery was serendipitous. The researchers were actually studying the stability of the WAIS.
"We were looking to better understand the role of the ocean in melting the ice shelf," lead author Brice Loose, from the University of Rhode Island, said in a statement. "I was sampling the water for five different noble gases, including helium and xenon. I use these noble gases to trace ice melt as well as heat transport. Helium-3, the gas that indicates volcanism, is one of the suite of gases that we obtain from this tracing method."
The team were worried at first that they had bad data but the presence of helium-3 was undeniable. Helium-3 can be used as a fingerprint for volcanism. The volcanic rift is under many kilometers of ice so without the chemical detections, they wouldn't have spotted it.
The WAIS is the fastest-melting glacier in Antarctica and the presence of a volcanic system suggests that volcanic meltwater is produced and then moved around underneath the Pine Island ice shelf. This, when combined with changes in winds and currents around Antarctica, has the potential to further damage the delicate glacier.
"The discovery of volcanoes beneath the Antarctic ice sheet means that there is an additional source of heat to melt the ice, lubricate its passage toward the sea, and add to the melting from warm ocean waters," co-author Professor Karen Heywood from the University of East Anglia, chief scientist on the expedition, added. "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."
There is a worry that the increase in melting could lead to a domino effect. As the ice sheet thins, the pressure on the mantle is lessened and more heat escapes. This, in turn, obviously increases the melting rate. It is unclear how long the system can remain stable.
"Predicting the rate of sea level rise is going to be a key role for science over the next 100 years, and we are doing that. We are monitoring and modeling these glaciers," Loose concluded.
