Περιβάλλον: Mega-canyon discovered beneath Greenland ice sheet

Hard, scientific data, turned into 3D animation - it's a newly discovered canyon lying beneath the 4 million year-old ice sheet in northern Greenland.
Scientists are calling it a mega-canyon. They say it's at least 750 kilometres long and up to 800 metres deep. A second animation shows the northern part of the canyon where it's deepest. The researchers say it's similar in scale to parts of the Grand Canyon. Teams from NASA and the UK and Germany pieced together thousands of kilometres of airborne radar data, collected over several decades, to build a picture of the canyon. They say it plays an important role in transporting sub-glacial meltwater from Greenland's interior to the edge of the ice sheet and ultimately into the ocean. Researchers now believe that the mega-canyon predates ice sheet inception and may have influenced hydrology in Greenland over past glacial cycles, spanning millions of years.

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