Scientists have revised the age of Earth's oldest known impact crater, the North Pole Dome in Western Australia's Pilbara region, down to about 3 billion years old — approximately 470 million years younger than earlier estimates. A 2023 study had claimed "unequivocal evidence" that the crater formed 3.47 billion years ago, based on analysis of shatter cones. However, a subsequent study in Science Advances challenged that finding, arguing the impact occurred no earlier than 2.7 billion years ago. In the new research, published in the journal Geology, lead author Chris Kirkland and his team used advanced dating techniques on minerals such as zircon, apatite, calcite, and muscovite from shatter cones and a shocked quartz vein. They found that zircon crystals exhibited unusual branching shapes, interpreted as impact-modified crystals formed from intense heating. The ages recorded in zircon matched those in apatite, giving the team confidence that the impact happened a little more than 3 billion years ago. The researchers noted that earlier, younger shatter cones may have formed due to subsequent tectonic and thermal activity. Despite the age reduction, the North Pole Dome remains Earth's oldest known impact crater, beating the next-oldest, the Yarrabubba structure (also in Western Australia), by roughly 800 million years. It is also the only recognized impact crater from the Archean eon (4 billion to 2.5 billion years ago), a critical period for early continental formation.