From left, Reed Graham of Manitoba Historic Resources Management, Todd Kristensen of the Archaeological Survey of Alberta and Robin Woywitka of MacEwan University excavate an archaeological site in the Fort McMurray area. Brittany Romano/The Canadian Press
New research may have answered a long-standing mystery by providing a rough date for the earliest known humans in Canada’s oil sands region.
In a recently published paper, Professor Robin Wojvitka of MacEwan University in Edmonton says a combination of archeology and geology has revealed that people lived around Fort McMurray, Alta., at least 11,000 years ago and perhaps as long as 13,000 years ago.
“People were in the Fort McMurray area very early on,” Wojvitka said.
“Fort McMurray has been a nexus for millennia. It attracts people forever.
Scientists have long known that the region has a long human history. An archaeological site known as the Ancestral Quarry has yielded millions of artifacts since it was discovered there in the 1990s.
But setting dates for them was difficult.
Standard methods such as radiocarbon dating are out. The area’s acidic soils destroy the organic materials on which these techniques depend.
Sometimes scientists can use sedimentary layers in the ground to date artifacts. But this area has been so stable that there aren’t many places where sediments have been deposited.
So Woywitka and his colleagues tried something new.
They produced satellite maps that revealed the topography of the surface down to a few square meters. They used this information to find places where sedimentation was most likely to have occurred and selected five of them – one of them in the Ancestral Quarry.
Sediments from these sites were dated using a technique called infrared stimulated luminescence.
This technique uses the fact that sand grains collect tiny radioactive particles in their pores. These particles deteriorate at a certain rate when exposed to light. So the longer they were buried, the more particles there would be.
Infrared light causes these particles to release energy. This can then be measured to reveal when the host sand grains were buried, along with the stone tools buried next to them.
In this case the answer was 12,000 years, more or less a millennium.
“There’s more uncertainty than radiocarbon dating, but it’s better than nothing,” Wojvitka said.
The findings place these early humans right at the beginning of when this part of the world became habitable. The first inhabitants would have moved there within a few centuries of the catastrophic flood that drained glacial Lake Agassiz, a vast inland sea that once covered almost all of present-day Manitoba and half of present-day Ontario.
The date is not long after the first arrival of humans in North America, which most archaeologists believe happened about 16,000 years ago.
They would find a landscape far removed from the lush boreal forests and teeming wetlands that now cover much of northern Alberta.
“People encountered a much different environment than what we see today – open, dry, cold,” Vojvitka said. “Probably tundra or grassland.”
They probably hunted bison, Vojvitka said. Beyond that there is little that can be said.
“We don’t know if they came from the north or the south.”
Despite the prevalence of artifacts, scientists cannot fit them well into the cultural toolkits of other prehistoric people. The presence of material from other parts of the continent suggests trade networks with other areas, but little is known.
One thing can be said.
Woywitka points out that the flood that drained the Agassiz exposed both the good tool-making stone that attracted people to the area and the oil sands that attracted thousands of modern residents.
“People came before 13,000 to get these things,” he said. “We’re going to Fort McMurray today for resources.”
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This content appears as provided to The Globe by the original telegraph service. Not edited by Globe staff.
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