Scientists have discovered a valley a mile deep, hidden beneath the ice in West Antarctica.
The ice-filled rift basin is connected to the warming ocean, and may be contributing to the rapid ice loss in the region, they say. The West Antarctic Ice Sheet is losing ice faster than any other part of Antarctica, with some glaciers shrinking by more than a metre per year.
"Over the last 20 years we have used satellites to monitor ice losses from Antarctica, and we have witnessed consistent and substantial ice losses from around much of its coastline," says University of Aberdeen glaciologist Dr Robert Bingham, who discovered the valley.
"For some of the glaciers, including Ferrigno Ice Stream, the losses are especially pronounced, and, to understand why, we needed to acquire data about conditions beneath the ice surface."
Using an ice-penetrating radar system towed behind a skidoo, the team discovered a large valley, parts of which are a mile deep.
"If you stripped away all of the ice here today, you'd see a feature every bit as dramatic as the huge rift valleys you see in Africa and in size as significant as the Grand Canyon," says Bingham.
"This is at odds with the flat ice surface that we were driving across - without these measurements we would never have known that it was there."
The valley connects with the ocean and, says the team, could be making ice losses worse by steering coastal changes further inland.
"What's particularly important is that this spectacular valley aligns perfectly with the recordings of ice-surface lowering and ice loss that we have witnessed with satellite observations over this area for the last twenty years," says Bingham.