Researchers at The University of Texas at Austin have revised a significant aspect of Oklahoma’s geologic history, potentially impacting how major historical events in Earth’s life are interpreted. Beneath Ames, Oklahoma, lies an extensive meteor impact structure buried under sediment and known to be a substantial oil and gas producer.
For years, the Ames crater was associated with a series of meteor impacts in North America that occurred approximately 467.5 million years ago during the Ordovician Meteor Event. Some scientists suggested that Earth was once surrounded by an asteroid debris ring during this time. However, recent research demonstrated that the Ames impact actually occurred around 370 million years ago during the Late Devonian, nearly 100 million years later than previously thought.
Lead author Elizabeth Catlos explained that multiple dating techniques consistently indicated this younger age. The earlier date was based on biological evidence—fossils of ancient conodonts found in the rock—which were misinterpreted as contemporaneous with the impact. Catlos noted the fossils were likely much older and mixed into the rocks during the impact event.
The new zircon dating aligns the Ames crater’s formation with the Frasnian-Famennian mass extinction event around 372 million years ago, which significantly affected marine life. Zircon U-Pb dating is recognized as an accurate method for dating ancient events, as these crystals preserve unique structures formed under high pressures from impacts.
The team collaborated with NASA to confirm that the zircon crystals were altered by the meteor strike, utilizing advanced imaging techniques. Establishing precise dates for mass extinctions and major events is crucial for understanding Earth’s transformation over time. The research raises questions about whether extinction events were primarily due to external forces like meteor impacts or internal processes such as volcanic activity.
This study also honors former graduate student Andrew Parisi, who initiated the project and passed away before its completion. Co-author Michael Brookfield also died prior to publication, highlighting the collaborative effort behind this significant research.
