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

A series of five small black, jagged arrowheads increasing in size from the left to right of the of the photograph.

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. New research is shedding light on the artifacts unearthed in Alberta.