Scientists studying rocks in Western Australia's Pilbara region say they may have identified the oldest known impact crater on Earth, formed by an asteroid strike about 3.02 billion years ago.
The site, known as North Pole Dome, sits within the East Pilbara Terrane, a rare geological archive that preserves some of the planet's most ancient crust. Researchers from Curtin University and the Geological Survey of Western Australia used mineral dating to test whether the structure really records a single ancient impact event.
Minerals That Kept the Time
Instead of relying only on surface features such as shatter cones, the team examined tiny minerals altered by shock and heat. The key signal came from zircon, a crystal widely used to date very old rocks because it can retain uranium and lead for billions of years.
The study found unusual zircon grains with skeletal, branching forms, suggesting they were reshaped or regrown during the impact and the fluid activity that followed. Their age was calculated at 3,024 million years, with a small margin of error. A second mineral, apatite, produced a closely matching age of about 3,019 million years.
Lead author Chris Kirkland said the matching mineral systems act like a natural clock, helping pinpoint when the event occurred. The researchers argue that this combination strengthens the case for a major meteorite strike rather than a later geological disturbance.
Why the Discovery Matters
If confirmed, North Pole Dome would be older than Western Australia's Yarrabubba crater, long considered the oldest well-dated impact structure at around 2.2 billion years. The finding could help scientists better understand how asteroid impacts shaped early Earth's crust, moved heat and fluids through rock, and influenced the environments where early microbial life developed.
The claim is still being discussed in the scientific community, but the new study, published in Geology, adds a compelling piece to the puzzle of Earth's deep past. It also highlights how ancient minerals can preserve records of events that happened in a fraction of a second billions of years ago. Looking ahead, discoveries like this may sharpen our view of how planetary surfaces evolve and how early worlds become habitable.