Researchers from Bristol University in the United Kingdom, the British Antarctic Survey and NASA have discovered a massive canyon – more than twice the size of Arizona's Grand Canyon – beneath an ice sheet in Greenland.
According to Bristol University, the "mega-canyon" is more than 460 miles long and nearly a half mile deep. Scientists were able to piece together the landscape using thousands of kilometers of radar data. NASA, along with researchers from the U.K. and Germany, have been flying over the region for several decades collecting radar data by beaming radio signals through the ice sheet.
The ice is transparent to radio waves at certain frequencies, which can travel through the ice and bounce off the bedrock, making the canyon visible through the NASA-collected radar data. Researchers believe the canyon, which has the features of a meandering river, plays a vital role in transporting sub-glacial melt water from inland Greenland into the 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 fully explored and mapped," said Jonathan Bamber, professor of physical geography at Bristol University and lead author of the study. "Our research shows there's still a lot left to discover."
A large portion of the data used to discover the mega-canyon came from NASA's six-year Operation IceBridge, which collected data from 2009 through 2012, the largest airborne survey of polar ice ever flown. The canyon begins near the center of the island and extends toward the Petermann Glacier in northern Greenland near Canada.
Bamber's team published its findings Thursday in the journal Science. The study was funded by Ice2sea, a European program focused on continental sea-level rise, and the U.K.'s Natural Environment Research Council.
"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," Ice2sea Coordinator David Vaughan said in a statement.
Scientists have done similar work in Antarctica aimed at uncovering full mountain ranges, volcanoes and bodies of water that have been buried under ice sheets for centuries.