Revealed by heavily instrumented polar research aircraft, Lake Snow Eagle is covered by 2 miles of ice and lies in a mile-deep canyon in the highlands of Antarctica's Princess Elizabeth Land, a few hundred miles from the coast.

"This lake is likely to have a record of the entire history of the East Antarctic Ice Sheet, its initiation over 34 million years ago, as well as its growth and evolution across glacial cycles since then," said polar expert Don Blankenship, one of the paper's authors and a senior research scientist at The University of Texas at Austin's Institute for Geophysics. "Our observations also suggest that the ice sheet changed significantly about 10,000 years ago, although we have no idea why."

Because it lies relatively close to the coast, researchers think that Lake Snow Eagle might contain information about how the East Antarctic Ice Sheet first began and the part played by the Antarctic Circumpolar Current, a ring of cold water circling the continent that scientists think is responsible for keeping it cool.

The study appeared May 9 in the journal Geology.

The first hint that the lake and its host canyon existed emerged when scientists spotted a smooth depression on satellite images of the ice sheet. To confirm it was there, researchers spent three years flying systematic surveys over the site with ice penetrating radar and sensors that measure minute changes in Earth's gravity and magnetic field.