When it comes to ice, scientists are giving a whole new meaning to the phrase "bottoms up." Those massive ice sheets in Antarctica don't just grow on top when snow falls, they also grow from the bottom up, according to new research published Thursday.
Ice melts at the bottom of ice sheets, and the water helps the sheets slide across the ground below. But the water can refreeze to the bottom of the sheets and push them up, the researchers report in the online edition of the journal Science.
The base of a massive ice plateau on the East Antarctic ice sheet called Dome A is about 24 percent refrozen water, according to the team headed by Robin Bell, a geophysicist at Columbia University's Lamont-Doherty Earth Observatory.
"The ice sheets are not simple layer cake structures. Water moves around underneath the ice sheet and deforms" it, Bell explained.
Fausto Ferraccioli, a scientist with the British Antarctic Survey and co-author of the report, added that knowing how the ice is formed is critical in the search for the oldest ice and also in understanding how the ice moves.
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http://www.huffingtonpost.com/2011/03/03/antarctica-ice-sheets-gro_n_830976.html
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