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麻豆直播 researchers have determined the most precise age yet for the oldest known impact crater on Earth, providing new insight into how meteorite strikes shaped the planet during its earliest history.

The team from Curtin鈥檚 School of Earth and Planetary Sciences and the (GSWA) investigated rock formations at the in the Pilbara region of Western Australia, a site long debated as an ancient asteroid impact structure.

Using advanced mineral dating techniques, the researchers have now identified the clearest evidence yet that the impact occurred around 3 billion years ago.

Lead author , from the within Curtin鈥檚 School of Earth and Planetary Sciences, said the findings help resolve a longstanding question about the timing of the impact.

鈥淲hile the site had previously been identified as an ancient impact structure, its exact age remained uncertain,鈥� Professor Kirkland said.

鈥淭he impact left a 鈥榤ineral clock鈥� behind. By dating minerals that were remade or newly grown in the damaged rocks, we can now pin down when this extraordinary event happened.

鈥淭he key evidence comes from zircon, a tiny but extraordinarily resilient mineral that can keep geological time for billions of years. Some zircons at North Pole Dome have unusual branching, skeletal shapes. We interpret these as impact-modified crystals, formed when older zircon was disrupted, partly recrystallised, and in places regrown during the intense heating caused by the impact.

鈥淭hese zircon crystals record an event at about 3 billion years ago, which we believe is the best estimate for the impact.鈥�

Professor Kirkland said to confirm the result, the team analysed a second mineral, apatite, which formed as hot fluids moved through the shock-damaged rocks. This independent dating method produced the same age.

鈥淭he agreement between two different mineral systems gives us confidence that we are seeing the signature of a single major event 鈥� a meteorite impact,鈥� Professor Kirkland said.

鈥淭he new age places the North Pole Dome structure as Earth鈥檚 oldest known impact crater and the only recognised example from the Archean eon, a time when the planet鈥檚 earliest continents were forming.

鈥淎ncient impact craters are incredibly difficult to date because over billions of years, rocks are altered by heat, pressure and fluids, which can obscure or reset the original impact signals. What we鈥檝e been able to do here is separate the moment of impact from its long geological history.

鈥淭his discovery pushes Earth鈥檚 impact record deeper into geological time than any previously well-dated crater, offering a rare glimpse of the violent processes that shaped the early Earth.鈥�

GSWA Director of Geoscience Dr Simon Johnson said the results of the research were truly exceptional.

鈥淐ollaborations of this calibre are vital to unlocking the rich, complex geological story of our State and driving new scientific discovery,鈥� Dr Johnson said.

The study 鈥楬ow old is the North Pole Dome impact, Western Australia?鈥� was published in Geology and can be found online here: