|Diameter||30–70 km (19–43 mi)|
|Age||2229 ± 5 Ma|
|Municipality||Shire of Meekatharra|
Location of the crater in Western Australia
The Yarrabubba crater is an impact structure, the eroded remnant of an impact crater, situated in the northern Yilgarn Craton near Yarrabubba Station between the towns of Sandstone and Meekatharra, Mid West Western Australia. With an age of 2.229 billion years, it is the oldest known impact structure on Earth.
While the rim of original crater has been completely eroded and is not readily visible on aerial or satellite images; it is centered on a feature called the Barlangi Rock. The evidence for the extent of impact comes from the presence of shocked quartz and shatter cones in outcrops of granite interpreted to be near the centre of the original crater, and from geophysical data. The diameter of the original crater is uncertain, but has been estimated to be from 30 to 70 km (19 to 43 mi). In simulations an impactor of diameter 7 km on ice over granite was found to produce a crater of final diameter compatible with the Yarrabubba crater.
The impact has been dated to 2,229±5 million years ago, making it the world's oldest confirmed impact crater. This date places the impact at the end of the first period when the Earth was mostly or completely frozen, commonly called the Huronian glaciation.
The age finding was based on analysis of ancient crystals of the minerals zircon and monazite found in the crater. Scientists used uranium-lead dating to analyze the samples and to determine the age of the impact crater.