Humans began living in Fort McMurray, Alberta at least 11,000 years ago, scientists say
New research may have answered a long-standing mystery by pinning an approximate date on the earliest known humans in Canada’s tar sands region.
In a recently published article, Professor Robin Woywitka of MacEwan University in Edmonton says a combination of archeology and geology has revealed that people lived around Fort McMurray, Alberta at least 11,000 years ago. years and possibly as long as 13,000 years ago.
« People were very early in the Fort McMurray area, » Woywitka said.
« Fort McMurray has been a connection for millennia. It has always drawn people. »
Scientists have long known that the area has a long human history. An archaeological site known as the Carrière des Ancêtres has yielded millions of artifacts since its discovery in the 1990s.
But giving them dates was difficult.
Standard methods such as radiocarbon dating are outdated. The acidic soils of the region destroy the organic matter on which these techniques depend.
Sometimes scientists can use the sedimentary layers of the earth to date artifacts. But this area is so stable that there are not many places where sediments have been deposited.
So Woywitka and his colleagues tried something new.
They took satellite maps which revealed the surface topography to an accuracy of a few square meters. They used this information to find sites where sedimentation was most likely to have occurred and selected five, including one in the ancestor quarry.
The sediments at these sites were dated using a technique called infrared stimulated luminescence.
This technique exploits the fact that grains of sand collect tiny radioactive particles in their pores. These particles deteriorate at a known rate when exposed to light. So the longer they are buried, the more particles there will be.
Infrared light causes these particles to release energy. This can then be measured to reveal when the host sand grains were buried, as well as the stone tools buried next to them.
In this case, the answer was 12,000 years, plus or minus a millennium.
« There’s more uncertainty than radiocarbon dating, but it’s better than nothing, » Woywitka said.
The finds place these early people at the very beginning of when this part of the world became livable. The first inhabitants are said to have settled there a few centuries after 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 isn’t too long after the arrival of humans 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 northern Alberta.
« People are dealing with a very different environment than what we see today – open, dry, cold, » Woywitka said. « Probably tundra or grassland. »
They likely hunted bison, Woywitka said. Beyond that, there is little to say.
« Whether they come from the north or the south, we don’t know. »
Despite the proliferation of artifacts, scientists cannot fit them neatly into the cultural toolkits of other prehistoric peoples. The presence of materials from other parts of the continent suggests trade networks with other regions, but little is known.
One thing can be said.
Woywitka points out that the flood that drained Agassiz exposed both the good tool-making stone that drew people to the area as well as the oil sands, which drew thousands of today’s residents. .
« People came 13,000 people ago to get this stuff, » he said. « We’re going to Fort McMurray today for resources. »