Archaeologists have utilized X-ray fluorescence (XRF) to map a vast prehistoric trade network that once connected Hopewellian culture centers in the Great Lakes region to the northern Great Plains. The study identified high concentrations of Native Copper from Isle Royale in artifacts found as far west as the Dakotas, while red Catlinite (pipestone) from Minnesota was traced to ritual sites in the Ohio River Valley.
This research confirms the existence of a highly organized continental exchange system that predates European contact by over a millennium. The findings suggest that these materials were not merely traded for utility but played a vital role in inter-tribal diplomacy and religious ceremonies. Lead researchers noted that the scale of this network rivaled the complexity of European Bronze Age trade routes, highlighting the sophisticated logistics of ancient North American societies.