Buried under Greenland’s ice for millions of years, a deep river system has recently been discovered by scientists, and it is longer than the Grand Canyon system in the United States, although not quite so wide or deep. The 470 mile canyon appears, reported the Christian Science Monitor on Thursday, Aug. 29, may be as old as 38 million years – even older than the surrounding glaciers themselves.
The covering ice sheet is two miles thick, which has kept the huge Greenland ice canyon system hidden from eyes and cameras. But the ice is thinning at a record pace, and radar signs are now clear. And once the scientists knew what to look for, they found radar evidence dating back 40 years, and under-ice rivers appear to have been flowing as recently as 3.5 million years.
Then ice pressure would have pushed out most of the water, but some movement continues today. According to glaciologists from the University of Bristol, the canyon meanders under the ice, as part of a large river system, and the movement appears to be part of the island’s “plumbing system.” Glacier water flows out and ocean water pushes in.
Creating maps of the hidden system will help scientists all over the world to "understand how the ice sheet is presently routing mass out toward its edges and how the ice sheet and water underneath the ice will interact," reports Mark Fahnsetock, a geophysicist at the University of Alaska at Fairbanks.
"It didn't occur to me that the canyon could go that far inland," says Dr. Eric Rignot, a glaciologist at the University of California at Irvine. "We did not even bother looking at that." Now, scientists everywhere will be looking at Greenland’s ice canyon.