Mysterious volcanic glass found in western Canada reveals ancient trade secrets

In a discovery that’s rewriting the understanding of prehistoric trade in North America, researchers have found over 500 archaeological sites in western Canada containing volcanic glass—obsidian—that geologically shouldn’t be there.

A new study published on March 14 by the Archaeological Survey of Alberta offers the most comprehensive explanation to date: obsidian was traded across vast distances by Indigenous peoples thousands of years before European contact.

“Finding obsidian at an archaeological site is a bona fide indicator of long-distance trade among prehistoric populations,” said study author and archaeologist Tim Allan.

Tracing obsidian’s origins with X-ray technology

Using cutting-edge X-ray fluorescence technology, Allan analyzed 383 obsidian artifacts from 96 archaeological sites across Alberta. His findings reveal that the volcanic glass originated from four primary geological sources: Bear Gulch in Idaho, Obsidian Cliff in Wyoming, and Anahim Peak and Mount Edziza in British Columbia.

Some artifacts—including arrowheads and spear tips—traveled up to 750 miles from their source.

“A single piece of obsidian likely exchanged hands many times,” Allan explained, highlighting the complexity of trade networks that existed across prehistoric North America.

7,000-year-old site offers clues

One of the sites, known as GbQn-13, dates back approximately 7,000 years. The presence of obsidian at this and other ancient sites suggests robust trading relationships spanning generations and geography.

Allan believes these artifacts were not just utilitarian tools but were also part of dynamic social and economic exchanges among Indigenous communities.

Obsidian at bison jumps: A window into communal practices

A significant number of the obsidian artifacts were uncovered at “bison jumps”—steep cliffs used by Indigenous hunters to herd and kill bison en masse. These communal hunting sites were not only centers of food production but also, perhaps, of cultural and economic exchange.

“The distribution of obsidian at these sites may be related to communal bison hunting practices,” Allan said, though he adds that more research is needed to fully understand the connection.

River networks as ancient trade highways

The study also points to river systems as likely contributors to the widespread distribution of obsidian. These natural pathways would have enabled long-distance movement of goods and ideas across the continent.

“Indigenous communities were extremely interconnected prior to European contact and colonization,” Allan said. “These trade networks spanned thousands of kilometers. We are only scratching the surface of how complex relationships between different groups were.”

Alberta Obsidian Project sheds new light on prehistoric North America

This study is part of the Alberta Obsidian Project, a long-term research initiative aiming to map ancient trade and migration patterns through the analysis of volcanic glass artifacts.

By revealing the remarkable journey of a single piece of obsidian, the research offers a rare glimpse into the vibrant and interconnected world of prehistoric Indigenous North America.