While the rim of the 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 . This date places the impact in the early
Rhyacian, around the end of 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. At the time of its dating in 2020, it was the oldest known impact structure on Earth. However, the dating of this impact structure was later questioned, with a subsequent study suggesting that the impact happened considerably later, sometimes between 2.7 billion and 400 million years ago. == References ==