Some of Antarctica's ice sheet is formed by water re-freezing from below not just by snow falling on top as was traditionally thought, findings showed on Thursday that will help scientists project effects of climate change.
Experts are seeking to understand the frozen continent since even a small thaw could swamp low-lying coastal areas and cities. Antarctica contains enough ice to raise world sea levels by about 57 meters (187 ft) if it ever all melted.
A six-nation study of the jagged mountain range as high as the Alps that is buried under ice in East Antarctica found that almost a quarter of the ice sheet in the area was formed by a thaw and re-freeze of water from underneath.
Deep below the surface, ice flowing into narrow, submerged valleys often melted because of high pressure and heat from the earth below and re-froze when it was forced up again.
The scientists said that about 24 percent of the ice in an area around Dome A, a 13,800 feet high plateau the size of California that forms the top of East Antarctica, was formed by re-frozen ice.
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