Curtin University researchers discover world’s oldest meteorite crater in Pilbara from 3.5 billion years ago

Perth researchers have discovered the world’s oldest known meteorite impact crater tucked away in a remote part of the Pilbara. Researchers from Curtin University’s school of earth and planetary sciences and the Geological Survey of Western Australia made the find after examining “shatter cones” at the North Pole Dome, about 40km west of Marble Bar. Shatter cones occur when the shockwaves from a meteorite slamming into the Earth leave cone-shaped fractures in the rock face. They are rare geological clues for scientists. Those found by the Perth researchers showed evidence of a massive meteorite impact 3.5 billion years ago. It would have careened into the Earth at well over 36,000km/h, leaving a crater more than 100km wide and sending debris flying across the globe. Study co-lead Professor Tim Johnson said that until now, the “absence of any truly ancient craters” meant they have largely been ignored by geologists. “Before our discovery, the oldest impact crater was 2.2 billion years old, so this is by far the oldest known crater ever found on Earth,” Professor Johnson said. “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.” Fellow 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 the early environment on Earth. “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,” he said. Professor Kirkland said that it also “radically refines our understanding of crust formation” because the massive amount of energy generated by the meteorite hitting the ground could have shaped early Earth’s crust. “It may have even contributed to the formation of cratons, which are large, stable landmasses that became the foundation of continents,” he said.