An international team of researchers using radar data from NASA’s Operation IceBridge has discovered a previously unmapped canyon hidden for all of human history beneath 1.2 miles (2 km) of ice covering Greenland.
According to a paper published in the journal Science, the canyon runs from near the center of the island northward to the fjord of the Petermann Glacier.
It is at least 460 miles (750 km) long and in places as much as 800m deep and is on the same scale as parts of the Grand Canyon in Arizona, USA.
This remarkable feature is thought to predate the ice sheet that has covered Greenland for the last few million years and has the characteristics of a meandering river channel.
The scientists used thousands of miles of airborne radar data, collected mainly by NASA and researchers from the UK and Germany over several decades, to piece together the landscape lying beneath the ice sheet that covers most of Greenland and obscures it from view.
They believe the canyon plays an important role in transporting sub-glacial meltwater produced at the bed from the interior to the edge of the ice sheet and ultimately into the ocean.
Even before the presence of the ice sheet, going back at least four million years, the evidence suggests the canyon provided a pathway for water from the interior to the coast and was a major fluvial system.
“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. Our research shows there’s still a lot left to discover,” said lead author Prof Jonathan Bamber from Bristol University, UK.
Bibliographic information: Jonathan L. Bamber et al. 2013. Paleofluvial Mega-Canyon Beneath the Central Greenland Ice Sheet. Science, vol. 341, no. 6149, pp. 997-999; doi: 10.1126/science.1239794