The discovered ice may be the oldest remnant of buried glaciers in the Arctic

On a remote island in the Canadian Arctic, researchers have discovered the remains of an ancient glacier that may 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 consecutive years — in the Arctic, researchers report Jan. 1. Geology. For researchers eager to study the glacier, the clock is ticking, as human-caused climate change has exposed the long-stored ice to melt.

Like entries in the pages of a diary, gas bubbles, compounds and particles trapped in the icy layers of a glacier can provide information about the atmospheres and climates of millennia past. But there are precious few reports of such ice older than the last great expansion of the ice sheets, 26,000 to 20,000 years ago. Thus, the newfound ice could provide researchers with a rare chance to study the climate of the early Pleistocene epoch, during which the Earth underwent episodic ice ages separated by warm periods known as interglacials. “These [Pleistocene climate shifts] are analogous to what we might 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 Canada’s Nunavut Territory, when they came across the sites of several recent landslides that had been caused by melting permafrost. The landslides had exposed translucent bodies of ice layers that were buried several meters underground, right above the fossil forest. Much to Fortier’s surprise, radiocarbon dating of the organic matter in the ice revealed it to be over 60,000 years old. “I didn’t expect this at all,” he says.

Researchers are shown digging into the remaining glacier ice, which was exposed by the melting and collapse of previously frozen ground.Stéphanie Coulombe

Additionally, in the sediment layers above the ice, the researchers discovered a reversal in the alignment of magnetic minerals that corresponded to a reversal in Earth’s magnetic field approximately 770,000 years old, indicating that the ice was at least that old. And previous research had dated the fossil forest on which the glacier rested to about 2.8 to 2.4 million years ago, providing a maximum possible age for the ice.

The discovery is a testament to the durability of permafrost, Fortier says. While climate projections suggest that permafrost will melt completely in many regions by the end of the century, this preserved glaciation persisted during 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.”

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