In 1991, an oil company discovered a giant crater buried beneath Ames, Oklahoma. Further investigation led researchers to propose that the meteor responsible for the structure belonged to the many meteors that struck North America about 470 million years ago. However, a new dating challenges this version, while proposing a completely different context for this enigmatic crater. According to a study recently published in Meteoritics & Planetary Science, researchers dated zircon crystals from the site and found that Ames Crater likely formed about 370 million years ago, during the Late Devonian. That represents a huge 100 million year gap from the Ordovician meteorite event, when Earth experienced a huge increase in meteorite events about 467 million years ago. Importantly, this now temporally places Ames Crater within another significant period of geological history: the Frasnian-Famennian mass extinction, which dramatically reshaped Earth’s marine ecosystems. “No matter what technique we used, it came back to this younger signal,” Elizabeth Catlos, lead author of the study and an earth scientist at the University of Texas at Austin, said in a statement. “With this research, we’re basically taking a major pawn from the Ordovician meteorite event and throwing it into the Frasnian-Famennian event, and saying, ‘This is where this impact belongs.'” Truly shocking A giant rock from space crashing into Earth causes a series of changes to the local environment. Taking the Ordovician meteorite as an example, scientists have proposed that the enormous flow of chondrites from this period greatly contributed to the biodiversification of the Earth. A more recent study also reinforced the link between the ice age and this event, which would have generated so much dust that the Earth experienced global cooling. Approximate extent of the Ames impact crater. © Jstuby via Wikimedia Commons Meanwhile, Ames Crater is among the largest impact structures associated with the Ordovician event, with a diameter of about 15 kilometers (9 miles), according to the study. As a result, it has been an integral part of theories about the full implications of Ordovician meteors on Earth’s geological history. However, despite its importance, scientists had yet to collect high-precision data on the crater’s geochronological history, the team noted in the paper. A renewed perspective For the latest study, researchers studied zircon samples from the site using several different techniques, including uranium-lead dating, which revealed both the age of the crater and the shock pressure left by the meteor. The team then collaborated with NASA to confirm that the zircon crystals were indeed affected by the meteorite impact. A geological map indicating the types of rocks that form the Ames impact structure. The locations of oil and gas wells are indicated by arrows. © Catlos et al., 2026 According to the paper, there was a “recurrence of Devonian dates” in different grains and methods, providing strong statistical evidence that Ames Crater is younger than previously believed. It is possible that the younger zircon dates come from “later tectonic events,” but this is less likely since the crater is largely isolated from major and minor faults in Oklahoma, the team added in the study. Equally momentous Now, the renewed dates place Ames Crater in another significant period of Earth’s geological history, namely the Frasnian-Famennian mass extinction event. This period, which scientists have called the “most devastating biotic crisis” at the time, caused large portions of marine life to become extinct. To be clear, this particular meteor, which produced a 14-kilometer-wide crater, was too small to cause global extinction on its own (but given the timing, it probably added some insult to injury). The precise triggers for this extinction event are still unclear, although one leading theory concerns large-scale volcanism. In that sense, the latest findings may offer new insights into this particular mystery. As Catlos added in the statement, having a more accurate timeline for Earth’s major extinction events teaches us how our planet works, especially if competing theories involve volcanic eruptions and extraterrestrial forces.
