Buried beneath Oklahoma, a meteor crater’s age was just rewritten by nearly 100 million years — and tiny ancient crystals now link it to one of Earth’s most catastrophic mass extinctions
Beneath the Oklahoma plains, hidden under layers of sediment and invisible to the people living above it, sits a meteor crater miles wide. It has quietly shaped the region’s geology — and its oil fields — for longer than anyone realized.
For decades, scientists thought they knew exactly when it formed. That certainty is now gone.
New research suggests the crater’s accepted age may be off by nearly 100 million years. That’s a discrepancy large enough to pull it out of one chapter of Earth’s history entirely and drop it into another.
A crater hiding in plain sight
The Ames impact structure doesn’t look like much from above — because you can’t see it at all. It sits entirely underground, beneath the small town of Ames, Oklahoma, stretching for miles beneath the surface. Layers of sediment have buried it completely, leaving no visible scar on the landscape.
Despite its invisibility, Ames carries real weight — both scientifically and economically. The structure has long been a major producer of oil and gas, its fractured underground geology creating conditions that trap hydrocarbons. A crater that quietly does work, even if almost no one above it knows it’s there.
For decades, scientists had confidently placed it within a well-known cluster of ancient impacts. That classification wasn’t just a footnote — it shaped how researchers understood a broader chapter of Earth’s cosmic history.
The Ordovician Meteor Event — and why Ames seemed to fit
Around 467.5 million years ago, a striking number of major impact structures across North America appear to have formed within a relatively narrow window of time. Scientists call this the Ordovician Meteor Event, and it has fascinated researchers for years. The clustering is striking enough that some proposed an extraordinary explanation: Earth may have once been encircled by a Saturn-like ring of asteroid debris during the Middle Ordovician, gradually raining material down over millions of years.
Ames seemed to belong to this story. Researchers had dated the crater using conodont fossils — tiny teeth from ancient eel-like animals — preserved in the rock. Those fossils pointed clearly to the Ordovician era, and Ames was folded into the larger cosmic narrative as supporting evidence. It was a tidy fit. It was also wrong.
Why the fossil clocks were wrong
The problem with using conodont fossils as a timestamp is subtle but significant. Those teeth came from organisms that lived during the Ordovician — but the fossils themselves may have already been millions of years old by the time the asteroid actually struck.
A meteor impact doesn’t just punch a hole in the ground. It excavates, overturns, and mixes material from different depths and wildly different geological ages, throwing ancient sediment together with younger rock. That’s likely what happened at Ames. The conodont teeth gave researchers an Ordovician signal, but they were reading the age of the fossils, not the age of the impact. Lead author Elizabeth Catlos noted that no matter which technique the team applied, the results kept returning a much younger age than the fossils suggested.
Tiny crystals, a radically different timeline
To get a reliable date, researchers turned to zircon crystals extracted from granite altered by the impact. Zircon U-Pb dating is one of the most precise tools available for deep-time geology, capable of pinning events to within a few million years across hundreds of millions of years of history. Zircon also has another useful property: when subjected to extreme impact pressures, it recrystallizes in distinctive, detectable ways, recording the collision itself rather than just the surrounding geology.
To confirm the crystals had actually experienced impact conditions, the team worked with NASA to image them using cathodoluminescence and electron backscatter diffraction — techniques that reveal a crystal’s internal structure in extraordinary detail.
The result was unambiguous. The Ames impact occurred approximately 370 million years ago, during the Late Devonian — nearly 100 million years after the Ordovician Meteor Event. Co-author Danny Stockli described zircon dating as a way to “go back in time and learn about the major changes to Earth’s ancient landscapes.”
A mass extinction gets a new suspect
A date of roughly 370 million years ago places the Ames impact uncomfortably close to one of Earth’s most severe extinction episodes. The Frasnian-Famennian mass extinction, which occurred around 372 million years ago, wiped out a large proportion of marine life on the planet. Its causes remain debated.
Catlos described the finding as moving “a major pawn” out of the Ordovician Meteor Event and into the Frasnian-Famennian story — not a minor administrative change, but something that potentially reshapes how scientists think about what drove that extinction.
The broader question is one researchers have wrestled with for years: were Earth’s mass extinctions driven by cosmic impacts, volcanic activity, or some combination of both? Re-dating more impact structures across the continent, the team argues, could significantly sharpen that timeline.
What’s striking about the Ames finding is how long a confident answer held — and how much a handful of tiny crystals could unsettle it. If one buried crater’s story can be rewritten so dramatically, it’s worth asking how many others are still waiting for their dates to be corrected.
Learn more about these exciting findings here: Elizabeth J. Catlos, Andrew F. Parisi, Michael E. Brookfield, Timmons Erickson, Sean P.S. Gulick, Axel K. Schmitt, Daniel F. Stockli, Daniel P. Miggins, Ben Ruchte, Mark Cloos. The Ames impact structure, Oklahoma: New radioisotopic constraints and implications for North American impact chronology. Meteoritics, 2026; 61 (8): 2103 DOI: 10.1111/maps.70191
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