The unearthed ice could be the oldest buried remnant of a glacier in the Arctic

On a remote island in the Canadian Arctic, researchers have discovered remains of an ancient glacier which could be over a million years old. The discovery represents what may be the oldest glacial ice ever found buried in permafrost – ground that has been frozen for at least 2 continuous years – in the Arcticthe researchers report on January 1 Geology. For researchers eager to study glaciers, the clock is ticking, like climate change caused by human activity exposed the long-preserved ice to melting.

Like notes on the pages of a ship’s logbook, gas bubbles, compounds and particles trapped in the ice layers of glaciers can provide information about the atmospheres and climates of millennia past. But there are very few reports of such ice older than the last major ice sheet expansion, 26,000 to 20,000 years ago. The newly discovered ice could thus provide researchers with a rare opportunity to study the climate of the early Pleistocene epoch, during which the Earth went through episodic ice ages separated by warm periods known as interglacials. “These [Pleistocene climate shifts] they are analogs for what we may see in the future,” says geomorphologist Daniel Fortier of the University of Montreal.

In 2009, Fortier and colleagues were studying a buried fossilized forest on Bylot Island, in the Canadian territory of Nunavut, when they came across the sites of some recent landslides that were triggered by thawing permafrost. The slides revealed transparent, layered bodies of ice buried several meters underground, right above the fossil forest. To Fortier’s surprise, radiocarbon dating of the organic matter in the ice revealed it to be more than 60,000 years old. “I didn’t expect that at all,” he says.

Moreover, in the sediment layers covering the ice, the researchers discovered a corresponding reversal in the distribution of magnetic minerals reversal of the Earth’s magnetic field approximately 770,000 years old, indicating that the ice was at least that old. And previous research has dated the fossil forest on which the glacier rested to roughly 2.8 to 2.4 million years old, giving the largest possible age of the ice.

The discovery is proof of permafrost’s resilience, Fortier says. While climate projections suggest that permafrost will melt completely in many regions by the end of the century, this preserved glacier persisted through interglacial periods that were warmer than today, he notes. “I don’t think the permafrost will disappear so soon. The system is more resilient than we think.”