By David Malakoff
Nearly twelve hundred years ago, one the largest volcanic eruptions to strike North America in millennia rocked the landscape of what is now southeastern Alaska. According to geologists, over three days millions of tons of ash poured from a peak named Mount Churchill, creating a plume that likely rose twenty-five miles into the sky and could be seen from at least 300 miles away. Winds carried the cinders east across what are now Canada’s Yukon and Northwest territories, burying landscapes up to 900 miles away beneath blankets of ash inches-to-feet deep.
University of Alaska students under the direction of Gerad Smith excavate a Dene residence located just outside of the ash plume in Alaska to see if its population increased after the eruption. Though there’s evidence that the Dene moved south after the eruption, Smith found no evidence that they migrated north into Alaska. | Credit: Gerad Smith
Todd Kristensen and Courtney Lakevold at an archaeological site on O’Grady Lake in Canada’s Northwest Territories. They took core samples from the lake to reconstruct ecological impacts of the eruption. | Credit Michael Donnelly
A piece of Tertiary Hills Clinker from a quarry in Canada’s Northwest Territories. The glassy material has a distinct geochemical signature that archaeologists used to track its distribution before and after the eruption. | Credit: Michael Donnelly
The massive blast—which was roughly fifty times larger than the 1980 Mount St. Helens eruption—“was almost certainly a terrifying spectacle” for the small bands of hunter-gatherers who lived in the region, archaeologist Todd Jay Kristensen of the Archaeological Survey of Alberta wrote in a doctoral dissertation completed last year. But the rain of volcanic glass and toxic chemicals did more than just frighten the Dene (also known as the Athabaskan) people who lived in the region, it also destroyed salmon streams and killed plants that caribou needed to survive. And the loss of those food sources, Kristensen argued in his dissertation, triggered Dene migrations that ultimately had far-reaching consequences for human cultures across western North America. The migrations not only catalyzed the spread of technologies such as the bow and arrow and copper tools, but also led centuries later to the emergence of the Apache and Navajo tribes in southwestern North America. “The eruption was both this destructive and creative force,” said Kristensen. “It becomes the stimulus that causes people to say: ‘Let’s get out of here and find a place where we can thrive.’ And then they just kept moving.”
This is an article excerpt from the Winter 2021 edition of American Archaeology Magazine. Become a member of The Archaeological Conservancy for your complimentary subscription.