A team of international scientists has discovered a source of intense volcanic heat beneath Antarctica’s fastest-melting ice sheet.
Professor Karen Heywood from the University of East Anglia, who took part in a 2014 expedition to the icy continent, said the discovery is vital towards understanding why the ice caps are melting.
She said: “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.
“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.”
Lead researcher chemical oceanographer Professor Brice Loose, University of Rhode Island, discovered trace amounts of volcanic gases in the waters surrounding the ice cap during the expedition.
The volcanic gases, mainly helium-3, pointed towards a source of volcanic activity many kilometres below the surface of the ice.
The startling findings were published in the latest edition of Nature Communications, titled “Evidence of an active volcanic heat source beneath the Pine Island Glacier”.
Professor Loose said: “We were looking to better understand the role of the ocean in melting the ice shelf.
“I was sampling the water for five different noble gases, including helium and xenon.
“Helium-3, the gas that indicates volcanism, is one of the suite of gases that we obtain from this tracing method.”
Pine Island Glacier is part of the West Antarctic Ice Sheet which covers Antarctica in the Western Hemisphere.
In 2017, geologists from Edinburgh University discovered almost 100 volcanoes beneath the ice sheet.
Tectonic landforms reveal that the West Antarctic Ice Sheet (WAIS) lies atop a major volcanic rift system. However, identifying subglacial volcanism is challenging. Here we show geochemical evidence of a volcanic heat source upstream of the fast-melting Pine Island Ice Shelf, documented by seawater helium isotope ratios at the front of the Ice Shelf cavity. The localization of mantle helium to glacial meltwater reveals that volcanic heat induces melt beneath the grounded glacier and feeds the subglacial hydrological network crossing the grounding line. The observed transport of mantle helium out of the Ice Shelf cavity indicates that volcanic heat is supplied to the grounded glacier at a rate of ~ 2500 ± 1700 MW, which is ca. half as large as the active Grimsvötn volcano on Iceland. Our finding of a substantial volcanic heat source beneath a major WAIS glacier highlights the need to understand subglacial volcanism, its hydrologic interaction with the marine margins, and its potential role in the future stability of the WAIS