Data from the United States space agency, NASA (National Aeronautics and Space Administration) airborne science mission has revealed a 750-kilometer long bedrock canyon one mile (two kilometers) under the ice sheet of Greenland. This previously unknown chasm is even longer than the Grand Canyon in Arizona in the USA. Greenland is the largest island in the world and this continuous “megacanyon” underneath it is one of this year’s most significant discoveries.
Another Grand Canyon
This geological feature is 800 meters (a half mile) deep in certain sections and winds on a path that is very similar to one of America’s most awesome natural features. Researchers believed that four million years ago, a major river system flowed through the canyon much like the Colorado River shaped the Grand Canyon. This ancient river in Greenland is believed to be as long as the Rhone River in Europe.
Team effort
The study was recently published in the journal, “Science.” The lead author of the mapping study that led to this discovery, Prof. Jonathan Bamber, glaciologist from the University of Bristol (UK) said that this find attests to the reality that there is still much to be explored and mapped on the surface of the Earth. The features of the bedrock underneath continental ice sheets are still a big mystery.
The lead scientist of the study is Michael Studinger. Team members included Prof. Bamber and other scientists from the University of Bristol in the United Kingdom, as well as Urbino University in Italy, and the University of Calgary in Canada.
The team utilized data from airborne radar from NASA’s Operation IceBridge. This study is dedicated to learning more about polar ice. The researchers used data collected between 2009 and 2012. Greenland-wide data compiled by British and German scientist in the past few decades were used by the study proponents as well.
Seeing through ice
Greenland’s ice sheet has been covering much of the island for a few million years. The landscape underneath this vast ice sheet is virtually unknown. One of the instruments that gathered the data is the Multichannel Coherent Radar Depth Sounder which has the power to see through thick ice and into the bedrock underneath. Radio waves have the ability to penetrate ice. When it hits bedrock, the radio waves bounce off. The longer the radio waves bounce off, the deeper the canyon. The canyon extends from the island center and ends in the northern part of Greenland under the Petermann Glacier fjord.
Assumptions
The researchers surmise that the canyon under the Greenland ice sheet was important in bringing sub-glacial meltwater out to the Arctic Ocean at the very edge of the sheet. When temperatures fell, the canyon was buried under the ice that covered the island 3.5 million years ago and formed the ice sheet we see today. Scientists believe that the canyon is still an important system in the drainage of meltwater from the ice sheet.
This significant finding was a byproduct of a bigger study being conducted in Greenland in reference to rising global temperatures.
Photo Credit: Greenland’s vast ice sheet
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