This finding, carried out by a team of scientists from the School of Oceanography at the University of Rhode Island (USA), is essential to understand thestability of the West Antarctic ice sheet, of which the Pine Island Glacier is part. The study has been published in the journalNature Communications.
The document is based on research conducted duringa great expedition in 2014to Antarctica. They worked aboard an icebreaker, the RRS James Clark Ross, from January to March, during the Antarctic summer.
“We were looking to better understand the role of the ocean in melting the ice shelf. I was testing the water with five different noble gases, including helium and xenon. I use these noble gases to track the melting of ice and the transport of heat. .Helium-3, the gas that indicates volcanism, is one of the gases we obtained from this tracking method.“explains Brice Loose, leader of the work.
The West Antarctic Ice Sheet sits atop a major volcanic rift system, but there has been no evidence of current magmatic activity. The last activity of this type was 2,200 years ago.This was something totally new.
According to experts, the volcanic rift system makes it difficult to measure heat flux to the West Antarctic ice sheet. “You can’t directly measure the normal indicators of volcanism – heating and smoke – because the volcanic rift is under many miles of ice,” Loose said.
But as the team continued their research, they found large amounts of a helium isotope, which comes almost exclusively from the mantle. According to Loose, “when you find helium-3, it’s like a fingerprint for volcanism.”
“ The volcanic heat sources were found under the fastest moving and fastest melting glacier in Antarctica, the Pine Island Glacier ,” Loose said. According to scientists, it is losing gigatons of mass very fast (1 gigaton = 1 billion metric tons).
Is volcanism responsible for this general meltdown?
No. The recent discovery does not imply that volcanism is Pine Island’s main source of mass loss. What does happen is that this scientific proof of volcanism is a new factor to consider when monitoring ice sheet stability.
Based on measurements of isotopes of helium and noble gases, the thermal energy released by volcanoes and hydrothermal vents suggests that the heat source below Pine Island is about 25 times greater than most of the heat flux from an individual dormant volcano. .
“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 out to sea, and contribute to the melting of warm ocean waters. It will be important to include this in our efforts to estimate whether the ice sheet of Antarctica may become unstable and increase further increase the level of the r ma “says Karen Heywood of the University of East Anglia in Norwich (UK) and scientific expedition.
Recall that climate change is causing most of the glacial melt and this newly discovered heat source “is having an effect yet to be determined, because we don’t know how this heat is distributed under the ice sheet.”
Reference: Brice Loose et al. Evidence of an active volcanic heat source beneath the Pine Island Glacier, Nature Communications (2018). DOI: 10.1038 / s41467-018-04421-3
