Researchers at The University of Texas at Austin have significantly revised Oklahoma’s geologic history, impacting how major events in Earth’s life history may be interpreted. Beneath Ames, Oklahoma, lies a meteor impact structure, covered by sediment but important for both science and the oil and gas industry.
The Ames crater, previously linked to a cluster of meteor impacts from around 467.5 million years ago during the Ordovician Meteor Event, has been re-dated to about 370 million years ago in the Late Devonian period. This discovery, made through zircon crystal analysis, reveals it to be nearly 100 million years younger than previously thought.
Lead author Elizabeth Catlos explained that earlier datings relied on biological evidence, specifically conodont fossils from the Ordovician period. However, these fossils likely predated the impact. New zircon dating shows that the crater’s formation aligns with the Frasnian-Famennian mass extinction event, which occurred around 372 million years ago.
Zircon U-Pb dating is noted for its accuracy in pinpointing ancient events, while imaging techniques validated that the zircon crystals were altered by the meteor strike. Catlos emphasized the significance of precise dating in understanding extinction causes—whether from space impacts or Earth-based volcanic activity.
The research honors former graduate student Andrew Parisi, who initiated the project, along with contributions from others, including co-author Michael Brookfield, who passed away before publication. This work thus reshapes the narrative of Earth’s geological history and mass extinction events.
