The 2.7-million-year-old silt is a remnant of the verdant tundra that covered Greenland before it was entombed in ice, researchers report today (April 17) in the journal Science. The beryllium concentrations could only have been found in soils that have developed over hundreds of thousands of years, if not millions: "The soil had been stable and exposed at the surface for somewhere between 200,000 and one million years before being covered by ice," said Ben Crosby, a member of the research team from Idaho State University. [In Photos: See Greenland's Ancient Landscape] 
 
 "There was a really stable landscape on Greenland before the ice sheet came," said lead study author Paul Bierman, a geomorphologist at the University of Vermont. "[It's] a refrigerator that's preserved this antique landscape," Bierman said. If the soil under Summit has been buried for 2.7 million years, then the discovery implies the ice sheet has never fully melted, even when the Earth went through an incredible natural warming swing 130,000 years ago — one as warm as this century's predicted climate change. New look at old ice 
 
 The ancient soil was pulled from beneath the Greenland Ice Sheet in 1993, during the GISP2 deep-drilling project to reach the bedrock beneath Summit. "I was looking for a history of landscapes in ancient Greenland, and that mindset wasn't there 20 years ago. The beryllium-10 isotopes help researchers gauge the age of landscapes, because the isotopes only form in rocks and soil exposed at the surface; cosmic rays can't penetrate thick ice or deeply buried rocks.
– The soil under the highest point of the Greenland Ice Sheet, scientists have learned, is 2.7 million years old, LiveScience reports. In other words, the silt buried under thousands of feet of ice "has been preserved from beyond the dawn of humankind," says Paul Bierman, who determined the soil's age through a geochemical dating process. The findings also suggest Greenland wasn't always as frosty as it is today: Instead, it was a tundra for between 200,000 and one million years before it was encased in ice. It was once home to bits of forest, the scientists found using offshore plant DNA. In other words, as the International Business Times has it, "Greenland really was green." The Greenland Ice Sheet that's there now, however, has been remarkably durable: The findings imply that it made it through a strong period of warming some 130,000 years ago. "It's unlikely the ice sheet has disappeared for significant periods of time in the last three million years, at least at this one pinprick on this big island," Bierman says. "Now human activity may spell the end of it." (What else lies under Greenland's ice? A canyon that dwarfs the Grand Canyon, an aquifer holding 100 billion tons of water, and two huge lakes.)