3-Million-Year-Old Tundra Landscape Found Beneath Greenland Ice Sheet
Posted on April 21, 2014
Scientists have discovered an ancient tundra landscape preserved under the Greenland Ice Sheet. The 3-million-year-old tundra landscape is preserved underneath 2 miles of ice. The discovery was reported in the journal, Science.
University of Vermont geologist and lead author Paul Bierman, says in a statement, "We found organic soil that has been frozen to the bottom of the ice sheet for 2.7 million years."
The discovery indicates the center of Greenland remained stable even during the warmest periods since the ice sheet formed. The researchers tested seventeen samples of "dirty ice" - ice with sediment mixed in - from the bottommost 40 feet of the 10,019-foot GISP2 ice core extracted from Summit, Greenland, in 1993. Researchers extracted a rare form of the element beryllium, an isotope called beryllium-10, from the sediment. The isotope is formed by cosmic rays. It falls from the sky and sticks to rock and soil. Geologists can measure how much of the rare element is in the soil to estimate how long the ancient soil was not frozen over. The data indicates the soil had been stable and exposed at the surface for somewhere between 200,000 and one million years before being covered by ice.
Dylan Rood, a co-author on the new study, from the Scottish Universities Environmental Research Centre and the University of California, Santa Barbara, says, "Greenland really was green! However, it was millions of years ago. Before it was covered by the second largest body of ice on Earth, Greenland looked like the green Alaskan tundra."