Ancient Lake Discovered Under Greenland May Be Millions of Years Old, Scientists Say

Scientists have discovered an ancient lakebed buried under a mile of ice in Greenland, providing a glimpse of what the remote region looked like in the past—and how it might look in a future shaped by human-driven climate change.

The bygone lake once covered an area of about 2,700 square miles, which is about the size of Rhode Island and Delaware combined. Though the basin is now filled with ice and sediment, it contained some 140 cubic miles of liquid water hundreds of thousands—or perhaps even millions—of years ago, according to a study published on Tuesday in Earth and Planetary Science Letters.

The sedimentary material that has piled up inside the lakebed could “contain valuable archives of regional past ice sheet extent and environmental conditions” and “may yield important insights into understanding climate” during warmer periods of Greenland’s past, said a team led by Guy Paxman, a postdoctoral researcher at Columbia University’s Lamont-Doherty Earth Observatory, in the study.

Paxman and his colleagues called the ancient lakebed Camp Century Basin because it is located near the abandoned American military base of the same name. The researchers spotted the frozen lakebed through the ice with the help of airborne instruments, including radar, carried by NASA’s Operation IceBridge research fleet.

The exact age of Camp Century Basin will be tricky to pin down just by looking at its imprint from the air. Its position deep under the ice sheet suggests that it first formed when this region of northwest Greenland was warmer and ice-free. These types of conditions may have cropped up many times over the past several million years as glaciers advanced and receded, so scientists would need a direct sample of the submerged basin to pinpoint the exact age of the lake that once existed there.

Given that Camp Century Basin is located under more than a mile of ice, it would require a sophisticated drilling effort to extract such a sample. However, past expeditions have plumbed ice to depths of two miles, so scientists may be able to eventually access some of the geological goodies that have been hidden in this lakebed for eons.

Of course, it would be fascinating to peer at a sedimentary time capsule of ancient Greenland, especially given that drilled samples might contain fossils of animals and plants that lived in and around the lake. But Paxman and his colleagues also emphasize the importance of the discovery for anticipating the environmental changes that come with the melting of these Arctic ice sheets.

“While northwest Greenland will potentially be a significant contributor to global sea level rise in the coming decades, the likely rate and magnitude of this change remain uncertain,” the team said in the study. “To this end, better constraining the behavior and extent of the [Greenland Ice Sheet] in northwest Greenland during past warm periods can aid our understanding of its response to current and projected future warming.”

The news was originally reported by Vice.