A team of geologists from Curtin University discovered clear evidence of a high-speed impact that occurred 3.47 billion years ago (Archean EON) in the heart of the Pilbara region of Western Australia. This discovery makes it the oldest impact crater found on Earth, surpassing the previous record of 2.2 billion years.
Grind cones from the Arctic Dome in the heart of Australia’s Pilbara region. Image credit: Curtin University.
“When more than a million craters with diameters exceeding 1 km and over 40 km, more than 100 km, the moon holds an exquisite record of the intense artillery fire that the body of the inner solar system has endured during the first billion years of its history.”
“On Earth, this early impact record appears to reflect the destructive efficiency of erosion and subduction, bringing the primary skin back to the convection mantle.”
“Nevertheless, the oldest part of many cratons, the ancient (4-2.5 billion years ago) nuclei of the continent formed 3.5 billion years ago, must maintain evidence of impact fluxes beyond similar regions of the moon of comparable age.”
“However, the oldest recognized terrestrial impact structure in Yarabuba, Western Australia dates 2.23 billion years ago. Where are Archean Craters?”
Professor Johnson and his co-authors investigated the Archiunlock Formation at the Arctic Dome in the Pilbara region and discovered evidence affecting major metstones 3.5 billion years ago.
“This discovery has challenged our previous assumptions about the ancient history of our planet,” Professor Johnson said.
Researchers discovered Archean Crater thanks to crushed cones. This is a unique rock formation that has only formed under the intense pressure of the Metstone strike.
The crushed cone at the site, about 40 km west of the marble bar, was formed when metstones over 36,000 km/h were pounded into the area.
This was a major planetary event, with craters over 100 km wide sending fragments flying around the world.
“We know that in the early solar systems, seeing the moon is common,” Professor Johnson said.
“To date, the absence of truly ancient craters means they are largely ignored by geologists.
“This study provides an important part of the puzzle of Earth’s impact history and suggests that there may be many other ancient craters that can be discovered over time.”
“The discovery shed new light on the way metstones formed the early environment of the Earth,” said Chris Kirkland, a professor at Curtin University.
“Discovering this impact and finding more from the same period can explain a lot about how life began, as impact craters created an environment that is friendly to microbial life, such as heated pools.”
“It also fundamentally refines our understanding of the formation of the earth’s crust. The enormous amount of energy from this impact may have played a role in shaping the early Earth’s crust by pushing part of the Earth’s crust underneath another or rising from deeper into the Earth’s mantle towards the surface.
“It may have contributed to the formation of the craton, the large, stable land that formed the foundation of the continent.”
Discoveries are reported in a paper In the journal Natural Communication.
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CL Kirkland et al. 2025. The Old Archian Impact Crater in Pyrabara Craton, Western Australia. Nut commune 16, 2224; doi:10.1038/s41467-025-57558-3
Source: www.sci.news
