Giant ice structures discovered under Greenland ice sheet

Monday, June 16, 2014, 7:40 PM - Researchers from Sweden and the U.S. have discovered a "mysterious world" in Greenland.

Ice-penetrating radar has unveiled blocks of ice as tall as skyscrapers in an area as wide as Manhattan at the bottom of Greenland's ice sheet.

Scientists believe the ragged blocks form as water at the surface refreezes and wraps around the ice over hundreds of thousands of years.

Upon analyzing Petermann glacier in northern Greenland, the team discovered that it is moving twice as fast as the ice around it. It's suspected that as meltwater at the bottom of the glacier refreezes it radiates heat into the ice sheet, making it move with greater ease.

Researchers hope the study will provide new insight into how glaciers behave and how they may respond to a warming climate.

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While scientists have known for some time that external forces like pressure and friction can melt the bottom of an ice sheet, it was previously unknown that this process could deform the higher-up layers and influence how a glacier behaves.

“We see more of these features where the ice sheet starts to go fast. We think the refreezing process uplifts, distorts and warms the ice above, making it softer and easier to flow,” Dr. Robin Bell, the study's lead author, said in a statement.

The theory builds on a 2011 study by Dr. Bell which suggests that ice sheets grow from the bottom up and not just from top-down snow accumulation.

The complete paper can be read online in the journal Nature.