Earth’s Oldest Impact Crater Found in Australia, Could Have Warmed the Planet 2.2 Billion Years Ago
Key Takeaways
- Yarrabubba crater in Western Australia, aged 2.2 billion years, is Earth’s oldest known impact site.
- The discovery adds over 200 million years to the previous impact record, previously held by Vredefort crater.
- Researchers determined Yarrabubba’s age by analyzing microstructures in crystallized rock from the impact site.
- The impact occurred at the end of a glacial period, potentially warming Earth by releasing 200 trillion kilograms of water vapor.
- Erosion and tectonic activity have erased evidence of most craters older than 2 billion years, making this find significant.
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A Record-Breaking Discovery
The Yarrabubba crater in Western Australia has been identified as Earth’s oldest recorded meteorite impact site, dating back 2.2 billion years, with a margin of error of 5 million years. This finding, published on January 21 in Nature Communications, surpasses the previous record-holder, South Africa’s Vredefort crater, by more than 200 million years. The crater lies on the Yilgarn craton, one of the planet’s oldest crustal regions, providing a unique window into Earth’s deep past.
Determining Yarrabubba’s exact age involved examining crystallized rock microstructures formed during the impact. Previous estimates placed the crater’s age between 2.6 billion and 1.2 billion years, but this new analysis narrows the timeline significantly.
Yarrabubba crater is now Earth’s oldest known meteorite impact site.T.M. Erickson
Implications for Climate and Geology
The timing of the Yarrabubba impact is particularly intriguing, coinciding with the end of an ancient glacial period. Using computer simulations, researchers estimated that the collision could have released up to 200 trillion kilograms of water vapor into the atmosphere. This massive release of greenhouse gases might have contributed to a global warming event, potentially melting ice sheets and altering the planet’s climate.
The discovery fills a critical gap in our understanding of ancient meteorite impacts and their effects on Earth’s environment. Most evidence of craters older than 2 billion years has been erased due to erosion and tectonic activity. Scientists have previously identified impact material older than 2.4 billion years in Western Australia and South Africa, but no corresponding craters were found until now.
Ancient depression
Timmons Erickson, a geologist at NASA’s Astromaterials Research & Exploration Science Division and coauthor of the study, highlighted the broader significance of the find. Not only does it expand the impact record, but it also offers insights into the interplay between meteorite impacts, climate shifts, and Earth’s geological evolution.
A Window into Earth’s Early History
Yarrabubba crater provides an exceptional opportunity to study how early impacts may have influenced the atmosphere and life on Earth. Its well-preserved state and precise dating mark a significant achievement in planetary science, helping researchers piece together Earth’s ancient history.
