Beneath the little town of Ames, Oklahoma, is something you would never guess was there.
A meteor crater roughly 9 to 10 miles across.
A conceptual cutaway of the Ames impact structure beneath present-day Oklahoma. The confirmed 14–16 km crater is buried beneath roughly 3 km of younger sediments; the exact underground appearance shown here is an artistic reconstruction. Illustration: Fact Fest.
You can't see it from the surface. Millions of years of sediment have buried it underground. But geologists can map the structure below.
The real subsurface geology of the Ames impact structure. Credit: Catlos et al. (2026).
For years, geologists thought they knew when that enormous crater was made: roughly 460–470 million years ago.
They had good evidence.
The witnesses were microscopic
Scientists had found microscopic fossilized remains of conodonts in material associated with the crater.
Conodonts were small, eel-like marine animals. Their tiny tooth-like feeding structures are especially useful for dating ancient rocks.
And these fossils were Ordovician.
About 467 million years old.
So the crater appeared to be about 467 million years old, too.
Perfectly reasonable.
Except there was a problem.
A second clock told a very different story
Researchers at the University of Texas at Austin tried dating something else.
Instead of asking fossils how old the crater was, they examined tiny crystals of zircon in granite affected by the impact.
Zircon can preserve the signature of an impact. These SEM examples are from Sudbury, not Ames. Image: Gavin Kenny, Swedish Museum of Natural History.
Zircon makes a remarkably good geological clock. Uranium atoms trapped inside the crystal slowly decay into lead at predictable rates.
The youngest Ames zircons pointed not to 467 million years ago...
…but to about 369.7 million years ago.
Nearly 100 million years later.
So which clock was wrong?
Neither.
The fossils were already old when the meteor arrived
Those ancient fossils really were about 467 million years old.
They were already there.
When the meteor struck, the tremendous impact excavated, shattered and rearranged ancient rock beneath the site.
Old fossil-bearing material was swept into the geological wreckage of a much younger impact.
Think of demolishing a 100-year-old house and finding a 200-year-old coin in the rubble.
The coin isn't lying.
It just doesn't tell you when the house was demolished.
One tiny fossil moves a meteor through time
Changing the date moves the Ames impact into an entirely different chapter of Earth's history.
Ames among North American impact structures from roughly 486–360 million years ago. Credit: Catlos et al. (2026).
Instead of belonging to the Ordovician Meteor Event around 467 million years ago, the new date places it in the Late Devonian.
That's intriguingly close to the Frasnian–Famennian mass extinction roughly 372 million years ago.
That does not mean the Ames meteor caused the extinction.
The researchers don't make that claim.
But it does move a major meteor impact nearly 100 million years through Earth's history simply because scientists found a better clock.
And there's a wonderful little lesson buried underneath Ames, Oklahoma:
The fossils weren't fake.
They weren't misidentified.
They weren't even the wrong age.
The evidence wasn't wrong.
We just asked it the wrong question.
Sources
University of Texas at Austin / Jackson School of Geosciences — research announcement.
Catlos et al., Meteoritics & Planetary Science — research paper.