New Evidence Dates an Oklahoma Meteor Strike to 100 Million Years Later Than Previously Believed

A meteor hit Oklahoma 100 million years later than scientists thought. That is the headline of a new study from the University of Texas at Austin, and the story is a reminder that the Earth’s past is full of surprises.

For many years, researchers have struggled to explain the Ames crater, which sits buried beneath the town of Ames, Oklahoma. The rock formation was thought to date back to the Ordovician Meteor Event, a series of major meteor impacts that spread across North America some 467.5 million years ago. Some scientists went further, proposing that an asteroid belt similar to Saturn’s rings may have once orbited the Earth, scattering waves of collisions across the continent.

The UT team’s findings now cast doubt on that idea. Associate professor Elizabeth Catlos and her colleagues have dated zircon crystals from the crater and determined that the meteorite hit around 370 million years ago, during the Late Devonian. That places the impact nearly 100 million years later than earlier estimates.

The Crater and Its History

Oklahoma’s oil and gas industry depends heavily on the Ames impact structure. Sediment layers now conceal the crater, yet its scientific and economic importance endures. It was long assumed to be part of a group of major meteor impacts stretching across North America, dating back some 467.5 million years to a period known as the Ordovician Meteor Event.

A piece on the board of planetary history was the crater. That piece has been removed from its original position by the UT team and set down somewhere else altogether.

The Trouble With Fossils

The dating of the Ames impact relied solely on biological evidence prior to this research. Scientists discovered teeth belonging to an ancient eel-like creature known as a conodont, which were preserved within the rock. These fossils originated from creatures that existed during the older Ordovician period.

Catlos suggested that the teeth were likely millions of years old before the asteroid hit, with the collision probably churning up older material and mixing those fossils into the rocks while still preserving them. The zircon dating tells a very different story: it shows that the Ames crater could not have formed during the Ordovician Meteor Event.

“No matter what technique we used, it was coming back to this younger signal,” Catlos said. The work was published in July in Meteoritics & Planetary Science.

Zircon Crystals Tell the Story

Scientists use zircon U-Pb dating as one of the most precise methods for establishing the timing of events from long ago. These crystals hold tiny structures formed under the immense pressure of a collision, which they preserve.

The research was led by a team including Danny Stockli, who serves as dean of the Jackson School of Geosciences and is a co-author of the study, according to “These small crystals allow us to go back in time and learn about the major changes to Earth’s ancient landscapes,”.

The team collaborated with NASA to use cathodoluminescence and electron backscatter diffraction to examine the zircons, confirming they had been altered by the meteor strike. Zircon recrystallizes in a specific manner when subjected to the intense pressures of an impact, and these imaging methods reveal those changes, verifying that the crystals recorded the collision directly.

The zircon dating does more than correct the age of a single crater. It alters the narrative of the Late Devonian entirely. The crater now rests near the Frasnian-Famennian mass extinction event, which took place around 372 million years ago and removed a significant share of marine life from the planet.

A Mass Extinction Puzzle

Catlos argues that getting more exact dates for mass extinctions and other major events is essential for understanding how Earth has changed over time. A central question concerns what drove these extinctions: whether they were mainly caused by forces from space, such as meteor impacts, or by processes within Earth, including episodes of massive volcanic activity.

She said “With this research, we’re basically taking a major pawn out of the Ordovician Meteor Event and dumping it into the Frasnian-Famennian event, and saying, ‘This is where this impact belongs,'”, and her words carried a weight that lingered long after she spoke them.

Andrew Parisi, a former graduate student at the Jackson School of Geosciences, started the project before graduating in 2018, though he has since died. He went to Oklahoma to acquire the Ames rock core from the Oklahoma Geological Survey, removed zircon crystals from it, and assisted in figuring out their ages.

The paper’s co-author, Michael Brookfield, who held the role of affiliated researcher at the institution, died prior to publication.

A New Piece of the Puzzle

The Frasnian-Famennian mass extinction event, which took place roughly 372 million years ago and claimed a vast share of marine life on Earth, now sits near the time of the Ames impact structure instead of the Ordovician Meteor Event. The study’s conclusion is that the crater’s revised dating puts the structure in the Late Devonian period.

A fresh sequence of dates has emerged from the study, and the UT team’s findings carry weight for how scientists understand the history of life on our planet.

The revised timeline indicates the Ordovician Meteor Event might not have been as widespread as earlier estimates suggested. Of all North American impact structures, only the Ames crater has been attributed to that episode by researchers.

The Research Team

A paper called “The Ames impact structure, Oklahoma: New radioisotopic constraints and implications for North American impact chronology,” which appeared in Meteoritics & Planetary Science, lists these researchers among its contributors: 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, and Mark Cloos.

NASA supplied the imaging methods that confirmed the zircon samples, supporting the team’s research.

The UT team’s work is part of a broader effort to understand the timing of major events in Earth’s history. The Frasnian-Famennian extinction has long been a puzzle for paleontologists, and the Ames crater now offers a new point of reference.

Hundreds of millions of years after an asteroid struck Earth, the record of that moment still exists inside the zircon crystals. These crystals are small, but they hold a memory that endures. A team from UT has studied these markers and discovered something unexpected.

The Ames crater is part of a pattern. It shows that Earth’s past is not fixed and unchanging. Instead, it is a living narrative, rich with surprising twists and concealed links. The UT researchers have moved to the next chapter, and the tale continues to evolve.

Source material: “A meteor hit Oklahoma 100 million years later than scientists thought,” ScienceDaily.

Devonian · mass extinction · meteor impact · Oklahoma · zircon dating