OLDEST ASTEROID CRATER ON EARTH DATED TO 3 BILLION YEARS AGO

Researchers from Curtin University have determined that the oldest known asteroid crater on Earth formed approximately 3 billion years ago, according to a study published in the journal Geology. The crater is located at the North Pole Dome in the Pilbara region of Western Australia, a site long suspected of being an ancient impact structure. Scientists used advanced mineral dating techniques to establish the precise age of the formation, resolving uncertainty that had persisted around the site's timeline. Chris Kirkland, an author of the study, stated that the impact left behind a "mineral clock" that enabled researchers to determine when the event occurred.

The research team analysed zircon minerals found in the damaged rocks at the impact site. They identified zircon formations with unusual branching and skeletal shapes, characteristics believed to have resulted from the asteroid impact and the intense heating it generated. Some zircon crystals showed signs of partial recrystallisation and regrowth caused by the impact's extreme temperatures. To confirm their findings, researchers examined a second mineral, apatite, which formed as hot fluids moved through the shock-damaged rocks following the impact. Dating the apatite mineral produced results consistent with the zircon analysis.

Dating geological formations billions of years old presents substantial technical challenges, as heat, pressure and fluids alter rock structures over extended periods. The study's findings provide new insight into Earth's earliest history and the frequency of asteroid impacts during the planet's formation. The research represents an update to previous estimates of the crater's age and establishes a new benchmark for understanding early planetary bombardment.