Obsidian artifacts unearthed in Alberta offer new clues on prehistoric trade routes

Inky black shards of volcanic glass unearthed in Alberta are helping researchers trace the movements of Indigenous people across Western Canada centuries ago. 

Hand-carved arrowheads and jagged spears made of obsidian, a sharp rock formed by volcanic magma, are remnants of vast prehistoric trade networks that once cut across western North America.

No volcano has ever erupted in Alberta, meaning every shard of obsidian found in the province was carried here. With X-ray technology, researchers can trace each piece back to its source.

A new paper examining artifacts unearthed from Alberta's eastern slopes suggests bison hunting in the southern foothills and a vast exchange network along the province's northern rivers helped distribute the stones across the province. 

Archaeologist Timothy Allan, the report's author, said he wanted to better understand Alberta's role in a vast Indigenous trade network that once spanned more than three million square kilometres.

A single piece of obsidian likely changed hands many times.

"The sheer scale of obsidian trade tells us that likely millions of people were in contact with one another," said Allan, who works with Ember Archaeology, an archaeology and historic resources consulting firm based in Sherwood Park, Alta.

"The scope of the trade network was way more massive than we thought." 

Understanding the journeys of obsidian artifacts can provide new insight into how people moved across the landscape and the complex cultural ties that shaped the continent centuries ago, Allan said.

"It's definitely part of our role in reconciliation, as archaeologists, to help tell these stories."

The research, published by the Archaeological Survey of Alberta, is the latest offering from the Alberta Obsidian Project, an ongoing collaboration of researchers and archaeologists examining the province's vast obsidian record.

Over the past decade, project researchers have studied and catalogued more than 1,200 Alberta obsidian artifacts.

The artifacts and the trade itself date back to a period between 13,000 and 300 years ago, before European contact. 

More than 520 archaeological sites have been identified in the province. The eastern slopes, which stretch from the alpine slopes of the Rockies down to the foothills, offer the most specimens.