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Massive canyon lies beneath Greenland ice sheet
By AFP | AFP – Thu, Aug 29, 2013

This NASA Earth Observatory image, captured during an IceBridge flight and released May 3, 2012, shows a glacier in eastern Greenland. A huge canyon twice the size of the longest river in Britain and as deep as the Grand Canyon lies beneath the ice sheet in Greenland, scientists said Thursday

http://uk.news.yahoo.com/video/giant-canyon-discovered-under-greenland-094100902.html

A huge canyon twice the size of the longest river in Britain and as deep as the Grand Canyon lies beneath the ice sheet in Greenland, scientists said Thursday.

Prior to the establishment of the ice sheet some four million years ago, the canyon is believed to have been a major pathway for water from the interior of the land mass to the coast.

Even today, the deep river channel -- which originates in the center of Greenland and terminates at its northern coast -- transports sub-glacial meltwater to the edge of the ice sheet and then into the ocean.

"A 750-kilometer (460-mile) 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," said David Vaughan of the British Antarctic Survey.
"This area's ice sheet contributes to sea level rise and this work can help us put current changes in context."

Scientists found the canyon using airborne radar data, much of which came from a NASA mission called Operation IceBridge, which used radio waves that traveled through the ice to measure the depth of the bedrock.

The Greenland sub-ice canyon is about twice as long as the River Severn in Britain, which extends 350 kilometers.

Michael Studinger, Operation IceBridge Project Scientist at NASA Goddard Space Flight Center, described the finding as "quite remarkable."

"It shows how little we still know about the bedrock below large continental ice sheets."
The study was published in the US journal Science.

http://uk.news.yahoo.com/massive-canyon-lies-beneath-greenland-ice-sheet-200615828.html?vp=1#XgAP7aX

A mega-canyon on the same scale as the American landmark lies buried under ice in Greenland, according to scientists

Vast canyon discovered under Greenland ice

http://uk.news.yahoo.com/video/vast-canyon-discovered-under-greenland-060218272.html

A vast and previously unmapped gorge, 800 metres deep, has been found under ice in Greenland. The canyon is 750 kilometres long and is said to be comparable in scale to parts of the Grand Canyon that is twice as deep – 1.6 kilometres – at its deepest. The Greenland canyon is buried under deep ice. Scientists used airborne data collected mainly by NASA and by scientists in Britain and Germany to piece together maps of the canyon.

Giant crack glimpsed in Antarctic ice sheet

A massive crack is growing wider in the Antarctic ice sheet and could break apart in the coming months, forming an iceberg the size of New York City, NASA scientists warned on Thursday.

The crack in western Antarctica's Pine Island Glacier stretches for at least 18 miles (30 kilometers) and runs 165 feet (50 meters) deep.

The rift is widening at a rate of 6.5 feet (two meters) per day, said NASA project scientist Michael Studinger.
When the ice breaks apart, it will produce an iceberg more than 340 square miles (880 square kilometers), said Studinger, who is part of the US space agency's IceBridge project.

But the process is not a result of global warming, he said.

"We expect that later this year or early next year there will be a pretty large iceberg forming as part of a natural cycle," he added.

"These are cyclical events that occur every few years. The last big calving event occurred in 2001, so in general people have been expecting something to happen like that very soon.

"For us it is very exciting to actually see this while it is happening."

The rift was first glimpsed in late September by scientists monitoring changes in the ice shelf via airplane flyovers in order to fill in the gaps left between a pair of satellites, ICESat (Ice, Cloud and land Elevation Satellite), which ended in 2009, and ICESat 2, which launches in 2016.

"A lot of times when you're in science, you don't get a chance to catch the big stories as they happen because you're not there at the right place at the right time," said John Sonntag, instrument team lead for Operation IceBridge, based at Goddard Space Flight Center.

"But this time, we were."