Scientists find out when humans first came to Alberta’s oil sands Globalnews.ca

New research may have answered a long-standing mystery by pinpointing an approximate date for the earliest known humans in Canada’s oil sands region.

In a recent article, Professor Robin Woywitka of MacEwan University in Edmonton says that a combination of archeology and geology has revealed that humans lived at Fort McMurray, Alta, at least 11,000 years ago and perhaps as much as 13,000 years ago.

“People were in the Fort McMurray area very early on,” Woywitka said.

“Fort McMurray has been a hub for millennia. It drew people in 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 it was difficult to give them dates.

Standard methods like radiocarbon dating are out. The area’s acidic soils destroy the organic materials on which these techniques depend.

Sometimes scientists can use layers of sediment in the earth to date artifacts. But this area was so stable that there are not many places where sediments were deposited.

So Woywitka and his colleagues tried something new.

They recorded satellite maps that reproduced the surface topography down to a few square meters. They used this information to find locations where sedimentation was most likely to have occurred and selected five of them – one of them in the ancestral quarry.

Sediments from these sites have been dated using a technique called infrared-stimulated luminescence.

This technique takes advantage of the fact that grains of sand collect tiny radioactive particles in their pores. These particles degrade at a known rate when exposed to light. So the longer they are buried, the more particles will be present.

Infrared light causes these particles to release energy. This can then be measured to show when the host’s sand grains were buried along with the stone tools buried next to it.

In this case the answer was 12,000 years, more or less a millennium.

“It’s less reliable than radiocarbon dating, but better than nothing,” Woywitka said.

The results put these early humans right at the beginning of when this part of the world became habitable. The first residents would have moved there within a few centuries after the cataclysmic flood that drained Glacial Lake Agassiz, a vast inland sea that once covered most of what is now Manitoba and half of what is now Ontario.

9:10
The history of the tar sands as seen by former Natural Resources Secretary Anne McLellan

The date isn’t too long after humans first arrived in North America, which most archaeologists believe happened around 16,000 years ago.

They would have found a landscape far removed from the lush boreal forests and teeming wetlands that now cover much of the North alberta

“People are dealing with a very different environment than today – open, dry, cold,” said Woywitka. “Probably tundra-like or grassland.”

They probably hunted bison, said Woywitka. Beyond that there is little to say.

“Whether they came from the north or the south, we don’t know.”

Despite the proliferation of artifacts, scientists cannot neatly fit them into the cultural toolboxes of other prehistoric people. The presence of materials from other parts of the continent suggest trade networks with other areas, but little is known.

One thing can be said.

Woywitka points out that the flood that drained Agassiz exposed both the fine tool-making stone that drew people to the area and the oil sands that have attracted thousands of modern residents.

“People came before 13,000 to get this stuff,” he said. “We’re going to Fort McMurray today for resources.”