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 …