Oklahoma Crater Dated to 370 Million Years Ago

Researchers determined the 10-mile-wide Ames crater formed significantly later than previously estimated.

Updated on Oct. 14, 2026 in Geology

A vast, ancient impact crater depression in the dry plains of northern Oklahoma under a bright, clear blue sky. — Geologists have re-dated the Ames crater in northern Oklahoma to 370 million years ago, linking the impact event to the Frasnian-Famennian extinction. AI Illustration. Upload story photo >

Geologists have re-dated the Ames crater in northern Oklahoma to 370 million years ago. This discovery shifts the impact timeline by 100 million years from the previous estimate of 467 million years.

Why it matters

The revised age aligns the impact timing with the start of the Frasnian-Famennian mass extinction event. This coincidence provides new data on whether the celestial collision contributed to the loss of half of all marine life.

Researchers analyzed high-pressure fracture patterns within zircon crystals extracted from the 10-mile-wide structure. The crater is currently recognized as the fourth-largest impact site in the United States.

The details

Oil prospectors originally discovered the Ames crater in 1991 while drilling in northern Oklahoma. Scientists utilized new techniques to study the crystals, which helped refine the dating of the high-pressure impact event.

1991: Oil prospectors discovered the crater.
370 million years ago: The Ames crater impact occurred.
372 million years ago: The Frasnian-Famennian mass extinction began.
467 million years ago: The Ordovician meteor event occurred.
July 7, 2026: The study was published in Meteoritics and Planetary Science.

The Big Picture

This discovery updates the geological timeline relative to the Frasnian-Famennian mass extinction. By re-dating the structure, scientists can better evaluate its role in Earth's history of catastrophic biological loss.

This scientific finding clarifies the geological history of the state, providing a more accurate record of ancient environmental changes. It helps experts refine models regarding how large-scale impacts have influenced Earth's long-term biological evolution.

The takeaway

This updated chronology highlights the importance of re-evaluating historical geological data with modern measurement techniques. Understanding the precise timing of ancient impacts is essential for mapping the development of life on Earth.