Scientists have discovered a large ancient lake bed that’s situated over a mile underneath ice in the northwestern part of Greenland. This is a huge news as it is the first ever discovery of its kind. While liquid water underneath ice has been previously found in Greenland and Antarctica, this is the first time that a fossilized lake bed with no current liquid water has been found that was formed when there wasn’t any ice in the area.
While the exact date of the lake bed is uncertain, it could be hundreds of thousands or even millions of years old. Fossils and chemical traces that should still remain in the lake bed would be exceptionally important in understanding the climate from ancient times in addition to experts predicting what may happen to the ice in the future.
But without being able to study the lake bed, it’s hard to know those exact details. “If we could get at those sediments, they could tell us when the ice was present or absent,” said Guy Paxman who is a postdoctoral researcher at Columbia University’s Lamont-Doherty Earth Observatory and the lead author of the study.
Researchers were able to find the lake bed by studying data collected from airborne geophysical equipment that was able to get images of what was underneath the thick ice. This mission was part of a project called NASA’s Operation IceBridge which is the biggest ever airborne survey of the polar ice regions. It is able to capture three-dimensional views of the Antarctic and Arctic ice sheets, sea ice, and ice shelves. The flight surveys of Antarctica normally occur in October and November, while Greenland is usually surveyed between March and May. (Pictures can be seen here.)
As for the ancient lake bed underneath Greenland’s ice, the lake would have been approximately 2,740 square miles with a depth of between 50 and 250 meters (164 to 820 feet). The basin’s sediments are about three quarters of a mile in thickness, while there are a minimum of 18 stream beds that were carved into an adjoining bedrock.
The lake may have been formed along a dormant fault line or perhaps a glacier carved out the spot and water slowly filled in as it melted. As for what types of sediments may be in the lake bed, it is currently unknown although previous discoveries of pollen along the edge of the ice sheet does indicate that plants (or possibly even forests) were once in that area and remains of those could be found hidden in the sediments.
The researchers wrote in part that the basin “may therefore be an important site for future sub-ice drilling and the recovery of sediment records that may yield valuable insights into the glacial, climatological and environmental history” although they would have to drill over a mile deep.
Their study was published in the journal Earth and Planetary Science Letters where it can be read in full.