Scientists Double Down on Age of Earth's Oldest Meteorite Impact Crater, Dating It, Again, at More Than Three Billion Years Old

Add as preferred source Large conical shatter cones within the Pilbara Craton, Western Australia Chris Kirkland / Curtin University After more than a year of controversy, scientists say they’ve used two geologic “clocks” to reconfirm that a site scarred by an ancient meteorite in Western Australia is more than three billion years old. They once again dub the feature the world’s oldest known impact crater, according to a study published on June 23 in the journal Geology. But the debate is far from settled; some experts remain unconvinced by the age described in the latest work. The North Pole Dome crater sits in the Pilbara region, which contains some of Earth’s oldest rocks—up to around 3.6 billion years old. That’s about one billion years after our planet formed, a time when it was being pelted by space rocks. “There’s very few places that are these deep time capsules that let us peer into the formative processes on our planet. That’s why they’re quite special,” study co-author Chris Kirkland, a geologist at Australia’s Curtin University, tells Petra Stock at the Guardian. Did you know? The oldest known Earth rocks Scientists reported last year that the oldest known fragments of our planet s crust are about 4.2 billion years old. They re located in Nuvvuagittuq Greenstone Belt in Canada. In March 2025, Kirkland and his colleagues reported that the impact crater was about 3.47 billion years old. Their analysis suggested that a space rock slammed into Earth at over 22,300 miles per hour, creating a 62-mile-wide basin. The age far surpasses that of Yarrabubba crater in Western Australia, which is dated to 2.2 billion years old and is regarded as Earth’s oldest known impact basin with a reliable age. However, some scientists refuted Kirkland and colleagues’ study, and one team even published their own study in July of last year, arguing that the North Pole Dome crater is less than 2.7 billion years old. “Both interpretations depended on matching ancient rocks across a complicated landscape,” Kirkland writes for the Conversation. “In the Pilbara, that is difficult work. Linking one fine-grained black rock to another across the outback can be surprisingly hard.” In the new work, he and his colleagues used two different methods to date the crater. First, they analyzed the age of tiny zircon crystals inside rock structures called shatter cones, which were shaped by the ancient asteroid strike. The mineral contains trace amounts of uranium, which slowly breaks down into lead. By measuring the ratios between the two elements, scientists can figure out when the crystal formed. The team also looked at another mineral called apatite, which forms when hot fluid moves through Earth rock fractured by the meteorite. Both clocks yielded an age of 3.02 billion years—younger than the researchers’ initial estimate, but still a record age. The findings hint that “very hot water” percolated through the rocks at that time, and only an impact by a space rock could explain the mineral changes seen inside the shocked rocks, Kirkland tells James Woodford at New Scientist. The combined apatite and zircon results provide “smoking-gun” evidence of the impact crater’s age, says Bruce Schaefer, a geochemist at Macquarie University in Australia who was not involved in the work. “It’s a real detective story,” he tells the Guardian. “The fact those two were reset at the same time is the really powerful evidence that this is the age of that event.” Still, some researchers remain unconvinced by the new dating techniques and age estimate. Alec Brenner, a planetary scientist at Harvard who co-authored the paper disputing the first study, stands by his original skepticism. “We’ve already documented shatter cones in nearby 2.77-billion-year-old rocks,” Brenner tells Yousuf Shameel and Kelly Gudgeon at the Australian Broadcasting Corporation. “That alone requires the impact happened after 2.77 billion years ago.” What’s more, he argues that the zircon could have formed from an unrelated fluid flow event. “I’d suggest they’ve dated an undocumented hydrothermal episode in the area,” Brenner says. Kirkland, however, stands by his findings, noting that the team has now directly dated minerals inside rocks broken by a meteorite. “The younger age argument still depends on long-distance correlation of undated rocks, largely from satellite-based mapping rather than direct geochemistry or geochronology,” he tells New Scientist. “We now have two mineral clocks from the impact rocks themselves giving the same age. That is why direct dating matters.” Sara Hashemi is a science writer and fact-checker currently based in New York City. Her work has appeared in Sierra, The Body, Maisonneuve magazine and more. Email Powered by Salesforce Marketing Cloud (Privacy Notice / Terms & Conditions)

Scientists Double Down on Age of Earth's Oldest Meteorite Impact Crater, Dating It, Again, at More Than Three Billion Years Old

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