New evidence that giant asteroid impacts created continents

Asteroid Collision Earth Impact
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Effects of asteroid collisions on Earth

New research has revealed evidence that the Earth’s continents were formed by giant meteorite impacts.

New research has revealed the strongest evidence yet that Earth’s continents were formed by the impact of giant meteorites, which were particularly prevalent during the first billion years of our planet’s four and a half billion year history. Curtin University researchers conducted the study, which was published in the journal Aug. 10, 2022. Nature.

Dr. Tim Johnson of the Curtin School of Earth and Planetary Sciences, The idea that the continents were originally formed by giant meteorites has been around for decades. However, until now there has been little hard evidence to support the theory.

“By examining tiny crystals of the mineral zircon in rocks that represent the best-preserved remains of ancient crust on Earth in the Pilbara Craton in Western Australia, we found evidence of these giant meteorite impacts,” he said. Johnson said.

“The study of the oxygen isotope composition of these zircon crystals revealed a ‘top-down’ process that started with the melting of near-surface rocks and deepened, consistent with the impact of giant meteorites.

“Our study provides the first solid evidence that the processes that formed the continents began with giant meteorite impacts similar to those responsible for the extinction of the dinosaurs, but billions of years ago.”

Understanding the formation and ongoing evolution of the continents Dr. Johnson, because these land masses host most of Earth’s biomass, all humans, and almost all of the planet’s important mineral deposits.

“At the very least, the continents contain critical metals such as lithium, tin and nickel, commodities essential to the emerging green technologies needed to meet our commitment to climate change mitigation,” said Dr. Johnson said.

“These mineral deposits are the end result of a process known as crustal differentiation that began with the formation of the earliest land masses of the Pilbara Craton, just one of many.

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

Reference: “Giant Impacts and the Origin and Evolution of the Continents” by Tim E. Johnson, Christopher L. Kirkland, Yongjun Lu, R. Hugh Smithies, Michael Brown, and Michael IH Hartnady, 10 Aug 2022, Nature.
DOI: 10.1038/s41586-022-04956-y

Dr. Johnson is affiliated with Curtin’s flagship geoscience research institute, the Geoscience Research Institute (TIGeR).

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