Evidence that giant meteor impacts created the continents

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Curtin’s 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 or so first billion years of the four-year history. billion and a half years of our planet.

Dr Tim Johnson, from Curtin’s School of Earth and Planetary Sciences, said the idea that continents originally formed on the sites of giant meteorite impacts had been around for decades, but until now there was little strong evidence to support this theory.

“By examining tiny crystals of the mineral zircon in rocks of the Pilbara Craton in Western Australia, which represents the best preserved remnant of Earth’s ancient crust, we found evidence of these giant meteorite impacts,” said Dr Johnson.

“Study of the oxygen isotope composition in these zircon crystals revealed a ‘falling down’ process beginning with the melting of rocks near the surface and progressing deeper, consistent with the geological effect of meteorite impacts. giantess.

“Our research provides the first strong evidence that the processes that eventually 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 Earth’s continents was crucial given that these landmasses are home to the majority of Earth’s biomass, all humans and nearly all of Earth’s significant mineral deposits. planet.

“Notably, continents are home to critical metals such as lithium, tin and nickel, commodities essential to the emerging green technologies needed to fulfill our obligation to mitigate climate change,” Dr Johnson said.

“These mineral deposits are the end result of a process known as crustal differentiation, which began with the formation of the first landmasses, of which the Pilbara Craton is just one of many.

“Data from other areas of ancient continental crust on Earth appear to show patterns similar to those recognized in Western Australia. We would like to test our findings on these ancient rocks to see if, as we suspect, our model is more widely applicable.”

The article, “The Impacts of Giants and the Origin and Evolution of Continents”, was published in Nature.

Lasers pave way for discovery of ancient crust beneath Western Australia

More information:
Tim Johnson, Giant Impacts and the Origin and Evolution of Continents, Nature (2022). DOI: 10.1038/s41586-022-04956-y. www.nature.com/articles/s41586-022-04956-y

Provided by Curtin University

Quote: Evidence that giant meteorite impacts created the continents (August 10, 2022) retrieved August 15, 2022 from https://phys.org/news/2022-08-evidence-giant-meteorite-impacts-continents.html

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