A new Australian study said that the Earth’s continents were formed by the impact of giant meteorites on Earth, during the first billion years of our planet’s life.
About 3.6 billion years ago, the Earth was a single large continent that scientists call the “Great Valpara” continent, and then that continent began to split for reasons about which scientists differed.
Some believe that the continents were divided due to the geological activity of the tectonic plates of the Earth, while others believe that the main driver of the division of the great continent is the “meteor impacts”, which fell on Earth in huge sizes more than 3.5 billion years ago.
Researchers from the Australian Curtin College of Earth and Planetary Sciences have provided evidence that may support the nary theory.
The researchers said in their study, published in the journal “Nature”, that “the Earth’s continents were formed by the impacts of giant meteorites that rained down on Earth during the first billion years of the planet’s formation” (the age of the Earth is 4.5 billion years).
“The secret is in the crystals”
Researchers say the idea that continents originally formed at the sites of giant meteorite impacts has been around for decades, but until now there has been little evidence to support that theory.
In their study, the researchers found the “evidence” by examining tiny crystals of the mineral zircon in rocks from Western Australia’s Pilbara Craton, which are Earth’s best preserved remnants of ancient crust. The researchers found by examining the giant meteorite impacts.
The Pilbara Craton is one of the oldest areas on Earth, and contains remnants of crust formed more than 3.1 billion years ago.
Examination of zircon crystals in that region revealed the presence of rock melting near the surface of the earth’s crust. This melting extends to the depth of the crust, consistent with the geological and thermal impact of a giant meteorite impact.
This research provides the first strong evidence that the formation of continents was initiated by the impact of a giant meteorite similar to that responsible for the extinction of the dinosaurs.
Earth is the only planet known to have continents, the planets of the entire solar system, as well as planets discovered outside our solar system, do not contain continents.
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