Researchers have discovered mountain ranges and three huge, deep subglacial valleys hidden beneath the Antarctica ice. The findings, published in the journal Geophysical Research Letters, are the first to emerge from extensive ice-penetrating radar data collected in Antarctica as part of the European Space Agency PolarGAP project.
Although there are extensive satellite data that help image the surface of the Earth and its deep interior, there was a gap around the South Pole area, which is not covered by satellites due the inclination of their orbits. The PolarGAP project was therefore designed to fill in the gap in the satellite data coverage of the South Pole and in particular acquire the missing gravity data.
Airborne radar data were also collected to enable mapping of the bedrock topography hidden beneath the ice sheet. The data reveals the topography which controls how quickly ice flows between the East and West Antarctic ice sheets. The team, led by researchers from Northumbria University in the UK, has mapped for the first time three vast, subglacial valleys in West Antarctica.
These valleys could be important in future as they help to channel the flow of ice from the centre of the continent towards the coast. If climate change causes the ice sheet to thin, these troughs could increase the speed at which ice flows from the centre of Antarctica to the sea, raising global sea levels.
The largest valley, known as the Foundation Trough, is more than 350 kilometres long and 35 kilometres wide. Its length is equivalent to the distance from London to Manchester, while its width amounts to more than one and a half times the length of New York’s Manhattan Island. The two other troughs are equally vast. The Patuxent Trough is more than 300 kilometres long and over 15 kilometres wide, while the Offset Rift Basin is 150 kilometres long and 30 kilometres wide.
“As there were gaps in satellite data around the South Pole, no one knew exactly what was there, so we are delighted to be able to release the very first findings to emerge from the PolarGAP project,” Kate Winter, a research fellow at Northumbria University.
“We now understand that the mountainous region is preventing ice from East Antarctica flowing through West Antarctica to the coast. In addition we have also discovered three subglacial valleys in West Antarctica which could be important in the future,” Winter said. “If the ice sheet thins or retreats, these topographically-controlled corridors could facilitate enhanced flow of ice further inland, and could lead to the West Antarctic ice divide moving,” she said.
“This would, in turn, increase the speed and rate at which ice flows out from the centre of Antarctica to its edges, leading to an increase in global sea levels,” she added. “By mapping these deep troughs and mountain ranges we have therefore added a key piece of the puzzle to help understand how the East Antarctic Ice Sheet may have responded to past change and how it may do so in the future,” Fausto Ferraccioli, principal investigator of the European Space Agency PolarGAP project.
“Our new aerogeophysical data will also enable new research into the geological processes that created the mountains and basins before the Antarctic ice sheet itself was born,” said Ferraccioli.