Curtin University | 2020 Jan 21
Yarrabubba crater for the first time, putting it at 2.229 billion years old – making it 200 million years older than the next oldest impact.
Lead author Dr Timmons Erickson ... together with a team ... from Curtin’s School of Earth and Planetary Sciences, analysed the minerals zircon and monazite that were ‘shock recrystallized’ by the asteroid strike, at the base of the eroded crater to determine the exact age of Yarrabubba.
The team inferred that the impact may have occurred into an ice-covered landscape, vaporised a large volume of ice into the atmosphere, and produced a 70km diameter crater in the rocks beneath.
Professor Kirkland said the timing raised the possibility that the Earth’s oldest asteroid impact may have helped lift the planet out of a deep freeze. ...
Precise Radiometric Age Establishes Yarrabubba, Western Australia,
as Earth’s Oldest Recognized Meteorite Impact Structure ~ Timmons M. Erickson et al
- Nature Communications 11:300 (21 Jan 2020) DOI: 10.1038/s41467-019-13985-7