The team calculated that the fragment struck Earth 3.5 billion years ago – more than one billion years earlier than the previous oldest crater confirmed in 2020.
Curtin said the impact would have been a “major planetary event” that would have created a crater more than 100km wide.
Professor Tim Johnson, the study’s co-lead, said the discovery significantly challenged previous assumptions about our planet’s ancient history.
“We know large impacts were common in the early solar system from looking at the Moon,” Professor Johnson said. “Until now, the absence of any truly ancient craters means they are largely ignored by geologists.
“This study provides a crucial piece of the puzzle of Earth’s impact history and suggests there may be many other ancient craters that could be discovered over time.”
Researchers discovered the crater thanks to ‘shatter cones’, which are distinctive rock formations only formed under the extreme pressure of a meteorite strike.
The shatter cones at the site, about 40 kilometres west of Marble Bar in WA’s Pilbara region, were formed when a meteorite slammed into the area at more than 36,000km/h.
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Co-lead author Professor Chris Kirkland, also from Curtin’s School of Earth and Planetary Sciences, said the discovery shed new light on how meteorites shaped Earth’s early environment.
“Uncovering this impact and finding more from the same time period could explain a lot about how life may have got started, as impact craters created environments friendly to microbial life such as hot water pools,” Professor Kirkland said.
“It also radically refines our understanding of crust formation: the tremendous amount of energy from this impact could have played a role in shaping early Earth’s crust by pushing one part of the Earth’s crust under another, or by forcing magma to rise from deep within the Earth’s mantle toward the surface.
“It may have even contributed to the formation of cratons, which are large, stable landmasses that became the foundation of continents.”
The news comes after NASA researchers visited the Pilbara region in 2023 to study its perfectly preserved “stromatolites”, which are thought to have been created by some of the earliest forms of life 3.5 billion years ago.
The agency hoped to use them to find similarities with Martian samples collected and confirm life was once present on the Red Planet. NASA’s Mars Perseverance rover began collecting samples in 2021 and hopes to eventually return them to Earth.
Adam Thorn
Adam is a journalist who has worked for more than 40 prestigious media brands in the UK and Australia. Since 2005, his varied career has included stints as a reporter, copy editor, feature writer and editor for publications as diverse as Fleet Street newspaper The Sunday Times, fashion bible Jones, media and marketing website Mumbrella as well as lifestyle magazines such as GQ, Woman’s Weekly, Men’s Health and Loaded. He joined Momentum Media in early 2020 and currently writes for Australian Aviation and World of Aviation.
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