Archaeologists have found meteorites, microspherules, iridium and platinum anomalies, and burned charcoal-rich habitation surfaces at 11 archaeological sites of the Hopewell culture in three states stretching across the Ohio River Valley. While Hopewell people survived the catastrophic event, which occurred between 252 and 383 CE, it likely contributed to their cultural decline.
“Direct positive evidence of catastrophic cosmic airburst and impact events have been found in the western hemisphere at the Cretaceous and Tertiary boundary approximately 65 million years ago and at the Younger Dryas boundary approximately 12,800 years ago,” said University of Cincinnati’s Professor Kenneth Tankersley and his colleagues.
“Both of these events are associated with global mass extinctions and they occurred before humans culturally evolved into complex, sedentary, agricultural-based societies.”
“The recent discovery of two Holocene cosmic impact events in Argentina (6,000 and 3,000 years ago), and one in Jordan (3,700 years ago), suggests that these natural catastrophes are far more common than previously suspected.”
“Between 1,800 and 1,431 years ago (220 and 589 CE), Chinese astronomers documented 69 near-Earth comets, including Haley’s, which came within 0.09 astronomical units of Earth in 374 CE (1,646 years ago.). At this time, human communities and the resources they needed for survival were at a heightened risk of being destroyed by a comet airburst event.”
“Archaeological evidence of ancient cosmic impact events has been recovered from archaeological sites of various ages in Europe, the Near East, and China,” they added.
“In the western hemisphere, Hopewell archaeological sites in the Ohio River valley contain an anomalously high concentration and diversity of meteorites when compared to all other cultural periods. They include iron meteorites, stony iron meteorites, and stony meteorites.”
In their new research, Professor Tankersley and co-authors used radiocarbon and typological dating to determine the timing of the catastrophic explosion.
They systematically investigated 11 Hopewell sites in the Ohio River valley.
“Twenty-nine radiocarbon ages establish that the event occurred between 252 and 383 CE, a time when 69 near-Earth comets were documented,” they said.
The researchers found an unusually high concentration and diversity of meteorites compared to other time periods.
The meteorite fragments were identified from the telltale concentrations of iridium and platinum they contained.
They also found a charcoal layer that suggests the area was exposed to fire and extreme heat.
“Micrometeorites have a chemical fingerprint. Cosmic events like asteroids and comet airbursts leave behind high quantities of a rare element known as platinum,” Professor Tankersley said.
“The problem is platinum also occurs in volcanic eruptions. So we also look for another rare element found in non-terrestrial events such as meteorite impact craters — iridium. And we found a spike in both, iridium and platinum.”
The Hopewell people collected the meteorites and forged malleable metal from them into flat sheets used in jewelry and musical instruments called pan flutes.
Beyond the physical evidence are cultural clues left behind in the masterworks and oral histories of the Hopewell.
A comet-shaped mound was constructed near the epicenter of the airburst at a Hopewell site called the Milford Earthworks.
“Various Algonquin and Iroquoian tribes, descendants of the Hopewell, spoke of a calamity that befell the Earth,” said Professor Tankersley, who is Native American.
“What’s fascinating is that many different tribes have similar stories of the event.”
“The Miami tell of a horned serpent that flew across the sky and dropped rocks onto the land before plummeting into the river. When you see a comet going through the air, it would look like a large snake.”
“The Shawnee refer to a ‘sky panther’ that had the power to tear down forest.”
“The Ottawa talk of a day when the sun fell from the sky. And when a comet hits the thermosphere, it would have exploded like a nuclear bomb.”
“And the Wyandot recount a dark cloud that rolled across the sky and was destroyed by a fiery dart.”
“That’s a lot like the description the Siberians gave for Tunguska.”
A paper on the findings was published this week in the journal Scientific Reports.
K.B. Tankersley et al. 2022. The Hopewell airburst event, 1699-1567 years ago (252-383 CE). Sci Rep 12, 1706; doi: 10.1038/s41598-022-05758-y