London: Researchers have discovered a one mile deep rift valley hidden beneath the ice in West Antarctica, which they believe is contributing to ice loss from this part of the continent.
Experts from the University of Aberdeen and British Antarctic Survey (BAS) made the discovery below Ferrigno Ice Stream, a region visited only once previously, over fifty years ago, in 1961, and one that is remote even by Antarctic standards.
Their findings reveal that the ice-filled ancient rift basin is connected to the warming ocean which impacts upon contemporary ice flow and loss.
The West Antarctic Ice Sheet is of great scientific interest and societal importance as it is losing ice faster than any other part of Antarctica with some glaciers shrinking by more than one metre per year.
Understanding the processes that influence ice loss from West Antarctica is important to improve predictions of its future behaviour in a warming world.
Dr Robert Bingham, a glaciologist working in the University of Aberdeen’s School of Geosciences and lead author of the study, discovered the rift valley whilst undertaking three months of fieldwork with British Antarctic Survey in 2010.
“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,” Dr Bingham said.
“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,” he said.
The team gathered the data using an ice-penetrating radar system towed behind a skidoo driven across the relatively flat ice surface, over a distance of 1500 miles – greater than that between London and Athens.
“What we found is that lying beneath the ice there is a large valley, parts of which are approximately a mile deeper than the surrounding landscape,” he said.
“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.
“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.
“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,” he added.
The study has been published in Nature.