In March 2025, researchers from the Curtins School of Earth and Planetary Sciences and the Geological Survey of Western Australia announced the discovery of Earth’s oldest impact crater, located in the very heart of the Pilbara region of Western Australia. Based on their field investigations, the crater formed about 3.5 billion years ago, making it the oldest known by more than a billion years — the previous record holder being the Vredefort structure in South Africa.

However, a new study challenges the initial findings by reassessing the age of the impact crater.

As study authors Aaron J. Cavosie, Professor for Earth and Planetary Sciences, Curtin University, and Alec R. Brenner, Postdoc at Yale University, write for the online magazine The Conversation, they discovered geological evidence suggesting the impact happened almost one billion years later than previously thought.

Both studies mapped the distribution of shatter cones, cone-shaped branching structures forming at the moment of impact, when shock waves shatter the bedrock.

The first study discovered shatter cones in 3.47 billion year-old sediment layers, deducing that the impact happened over 3 billion years ago. However, a more recent field survey discovered shatter cones also in basaltic lava covering the sediment layers, and therefore of younger age.

The impact had to occur after the formation of the youngest rocks that contained shatter cones, meaning sometime after the 2.77-billion-year-old basalt.

Based on the distribution of shatter cones and droplets of glass, formed when the impact energy melted Earth’s surface, the authors of the firsts study estimated that the outer crater was about 100 kilometers in diameter — making it one of the larger impact craters found on Earth. However, this approach tends to overestimate the true size of the crater. In the new study, the authors used instead the orientation of shatter cones to calculate the size of the original crater. Based on their results, the crater was significantly smaller, about 16 kilometers in diameter.

While this crater may not be the world’s oldest or largest, it remains scientifically unique. The crater formed in a large basalt plateau, unlike most other craters located in sediments or metamorphic rocks. The impact site also overlaps with the region where some of Earth’s oldest fossils were found, the authors note.

The authors of the new study also propose to name the crater “Miralga impact structure," after the Aboriginal name of the region.

The study,"," was published in the journal Science Advances.