Evidence that giant meteorite impacts created the continentsDate: August 10, 2022
Source: Curtin University
Summary: New research has provided the strongest evidence yet that Earth's continents were formed by giant meteorite impacts that were particularly prevalent during the first billion years or so of our planet's four-and-a-half-billion year history.
New Curtin research has provided the strongest evidence yet that Earth's continents were formed by giant meteorite impacts that were particularly prevalent during the first billion years or so of our planet's four-and-a-half-billion year history.
Dr Tim Johnson, from Curtin's School of Earth and Planetary Sciences, said the idea that the continents originally formed at sites of giant meteorite impacts had been around for decades, but until now there was little solid evidence to support the theory.
"By examining tiny crystals of the mineral zircon in rocks from the Pilbara Craton in Western Australia, which represents Earth's best-preserved remnant of ancient crust, we found evidence of these giant meteorite impacts," Dr Johnson said.
"Studying the composition of oxygen isotopes in these zircon crystals revealed a 'top-down' process starting with the melting of rocks near the surface and progressing deeper, consistent with the geological effect of giant meteorite impacts.
"Our research provides the first solid evidence that the processes that ultimately formed the continents began with giant meteorite impacts, similar to those responsible for the extinction of the dinosaurs, but which occurred billions of years earlier."
Dr Johnson said understanding the formation and ongoing evolution of the Earth's continents was crucial given that these landmasses host the majority of Earth's biomass, all humans and almost all of the planet's important mineral deposits.
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Source:
https://www.sciencedaily.com/releases/2022/08/220810123550.htm
