The North Pole Dome, also known as the Miralga impact crater, is considered one of the oldest confirmed asteroid impact structures on Earth. (Image: Curtin University)A massive impact crater in Western Australia could be the oldest known asteroid strike site on Earth, according to new research. However, the proposed age remains the subject of ongoing scientific debate.The structure, known as the North Pole Dome or Miralga impact crater, was first identified in 2025 by researchers led by geologist Chris Kirkland from Curtin University. The crater is estimated to stretch up to 100 kilometres across and contains distinctive shatter cones, rare geological features formed only by powerful impact events such as asteroid collisions.The original study suggested the impact occurred around 3.47 billion years ago, making it the oldest known impact crater on Earth. That estimate was based on the ages of surrounding rock layers rather than direct dating of the impact site itself.The claim was challenged by another research team, including Aaron Cavosie, who argued that the crater could be much younger, possibly no older than 2.77 billion years.Now, Kirkland and his colleagues have published new findings in GeoScienceWorld based on direct dating of minerals found within the impact rocks. Using uranium-lead dating techniques, the team examined zircon crystals altered by the impact force, along with apatite minerals formed by hot fluids generated after the collision.Also Read | Did Nasa just find evidence of ancient life on Mars? Perseverance detects complex organic carbonBoth mineral samples produced ages of roughly 3.02 billion years, leading the researchers to conclude that the asteroid strike likely occurred around that time.According to the team, the mineral changes observed in the rocks are difficult to explain through other geological processes such as mountain-building or regional heating. They argue that an asteroid impact remains the most likely cause.Story continues below this adDespite the new evidence, some scientists remain unconvinced. Cavosie says shatter cones also appear in younger rock formations nearby, suggesting the impact must have occurred after those rocks formed.For now, the North Pole Dome crater remains one of the oldest confirmed impact structures ever identified, even as researchers continue to debate exactly when the asteroid struck.