“We usually think of ice sheets like cakes—one layer at a time, added from the top,” said Robin Bell, a geophysicist at Columbia University's Lamont-Doherty Earth Observatory. “This is like someone injected a layer of frosting at the bottom—a really thick layer.”
Beneath Dome A, a plateau that forms the high point of the East Antarctic ice sheet, at least 24 percent of the ice formed from the bottom up. In other places, as much as half of the ice sheet is made up of this bottom-forming ice.