Greenland may have a few features that we weren't aware of. It turns out that a massive canyon, at some points on the same scale as the Grand Canyon, lurks beneath the Greenland ice sheet.
It wasn't easy detecting this canyon, which explains why it's remained hidden for so long. Scientists used thousands of miles of airborne radar data, mainly collected by NASA and researchers from the UK and Germany over several decades. This allowed them to piece together the landscape lying beneath the ice sheet that covers most of Greenland.
At certain frequencies, ice is transparent to radio waves which can travel through the ice and bounce off of the bedrock underneath. By analyzing the radar data in a consistent way, the researchers found a bedrock canyon that extends from almost the center of the island and ends at its northern extremity in a deep fjord connecting to the Arctic ocean.
"With Google Streetview available for many cities around the world and digital maps for everything from population density to happiness, one might assume that the landscape of the Earth has been full explored and mapped," said Jonathan Bamber, lead author of the new study. "Our research shows that there's a lot left to discover."
This canyon probably predated the ice sheet which has covered Greenland for the last few million years. Characterized by a meandering river channel, the canyon most likely plays an important role in transporting subglacial meltwater produced at the bed from the interior to the edge of the ice sheet and into the ocean. In places, the canyon plunges to below 2,000 feet.
"A discovery of this nature shows that the Earth has not yet given up all its secrets," said David Vaughan, ice2sea coordinator. "A 750-km canyon preserved under the ice for millions of years is a breathtaking find in itself, but this research is also important in furthering our understanding of Greenland's past. This area's ice sheet contributes to sea level rise and this work can help us put current changes in context."