End of Hopewell civilization still unclear
University of Cincinnati archaeologist Kenneth Tankersley and a team of six other researchers recently proposed that a comet exploded over what is now Cincinnati between AD 252 and 383.
They claim the explosion rained fire across southwestern Ohio incinerating the villages and farm fields of the ancient American Indian Hopewell culture; and the resulting loss of life and livelihood brought about the decline of this civilization. They presented these sensational claims in the February issue of the journal Scientific Reports.
These claims were widely and uncritically reported in the news media, but archaeologists who specialize in studying the Hopewell culture were deeply skeptical. So a group of us carefully reviewed Tankersley’s team’s evidence and conclusions. Ball State University archaeologist Kevin Nolan shared some of our group’s findings in a presentation at the Ohio Archaeological Council’s April meeting, which you can watch on the OAC’S Youtube page.
Tankersely’s team claimed they found high amounts of the rare elements platinum and iridium, which can occur in comets and meteorites, at all eleven Hopewell sites they studied. They also claimed to have found the remains of Hopewell villages consumed by the fires ignited by the “cosmic airburst event.”
After examining the original excavation reports, however, Nolan’s team was able to establish that none of the evidence for burning found at these Hopewell sites were from burned villages. For example, all the burned areas documented at the Turner Earthworks, located near Cincinnati, “at or near the epicenter” of the proposed explosion, are burned clay altars, burned layers in mounds, or small beds of ashes where ancestors had been cremated. They were not the result of a single catastrophic event, but fires intentionally lit for specific religious purposes at various times over the site’s history.
Another problem with Tankersley and colleagues’ argument is their assumption that the Hopewell culture experienced a “rapid cultural decline.”
In fact, the changes that archaeologists have identified that signal the end of the Hopewell culture and the beginning of something new don’t suggest anything like a rapid decline in response to a disaster.
In many ways, the Late Woodland cultures that came after the Hopewell were not all that different. The mostimportant changes included a shift away from building monumental earthworks and a reduction in the kinds of unusual raw materials used to make ceremonial regalia.
One thing that doesn’t seem to have changed was the number of people living in the region. That’s important, because if there had been the regionwide conflagration claimed by Tankersley’s team, the population would have experienced a dramatic decline.
Is it possible that a comet exploded over Ohio 2,000 years ago?
Sure. But there is no credible evidence for a cosmic catastrophe on the scale envisioned by Tankersley and his colleagues. They are wrong about the burned villages and the Hopewell decline. And there are other possible explanations for the platinum and iridium they claim to have found. For example, one of those unusual raw materials worked by Hopewell artisans was meteoric iron, brought to Ohio from as far away as Kansas.
Hammering and shaping this material would have left traces of these rare elements in the soil, so maybe that’s all Tankersley’s team found.
Sensational claims make for good clickbait, but without solid evidence to back them up, they’re not good science.
Brad Lepper is the Senior Archaeologist for the Ohio History Connection’s World Heritage Program
blepper@ohiohistory.org