“The Pilbara Craton in Western Australia is one of the best-preserved ancient crustal remnants on Earth, and by examining tiny crystals of the zircon mineral in rocks in the region, we have found evidence of a giant meteorite impact.” Curtin University Earth & Dr Tim Johnson of the School of Planetary Sciences said. Studying the composition of oxygen isotopes in zircon crystals, they discovered a “top-down” process — oxygen that begins with the melting of rocks near the surface and progresses deeper into the ground, consistent with the geological effects of giant meteorite impacts.
“Our study provides the first solid evidence that the eventual formation of continents began with giant meteorite impacts, leading to events like the extinction of the dinosaurs,” Dr Johnson said. He also said that understanding the formation and evolution of Earth’s continents is crucial. “It’s especially important that the continent hosts key metals such as lithium, tin and nickel that are essential to advancing the emerging green technologies needed to mitigate climate change.”
The research team plans to follow up to test the findings on rocks from other ancient continental crustal regions of the planet to verify that their model is broadly applicable.
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