Ames impact crater in Oklahoma dated 100 million years younger

Researchers at the University of Texas at Austin have determined that the Ames impact crater in Oklahoma formed approximately 370 million years ago, nearly 100 million years later than previously estimated. The 10-mile-wide subsurface structure was formerly thought to have been created 467 million years ago, linking it to a period of frequent meteorite strikes that some scientists suggest may have once formed a ring of asteroid debris around Earth.

Previous dating relied on fossilized teeth from conodonts, ancient eel-like creatures found at the site. However, researchers believe the impact may have jumbled older fossil material into the site, creating a false correlation. To achieve a more direct date, the team analyzed zircon crystals in granite affected by the collision. The radiometric dating of these crystals suggests the impact occurred near a major marine extinction event that took place roughly 372 million years ago.

The Ames impact structure remains a significant site today as a major producer of oil and gas.