If a series of colossal meteors had not struck the primordial Earth, we might not have come into existence or would not exist in the way we do today.
According to Science Alert, Earth is the only planet known to humanity that has continents. These continents have repeatedly come together to form supercontinents and then broken apart, as evidenced by the theory of plate tectonics. However, what created the first continent remains a mystery.
A team of scientists led by geologist Tim Johnson from Curtin University in Australia has analyzed the Pilbara Craton, the best-preserved piece of ancient Earth’s crust ever found on the planet, excavated from a volcanic mouth in Western Australia.
Ancient Earth, when it was still a molten sphere, greatly benefited from colossal meteors – (Photo: ASTRONOMY MAGAZINE)
This fragment of crust has revealed the composition and structure of a piece of ancient continent. It contains clear evidence of the impacts of ancient meteors before the earliest supercontinent of Earth broke apart.
Research on the oxygen isotope composition in zircon crystals within this ancient crust has revealed a “top-down” formation process for continents, starting from the melting of rocks near the surface and gradually progressing deeper, consistent with the geological effects of impacts from colossal meteors.
“Our study provides the first solid evidence that the processes of continental formation ultimately began with impacts from colossal meteors, similar to the agents that caused the extinction of the dinosaurs, but occurring billions of years earlier,” said Dr. Johnson.
The study examined 26 samples containing zircon fragments dated between 3.6 million and 2.9 billion years old, thoroughly analyzing the oxygen isotopes, specifically the ratios of oxygen-18 to oxygen-16. Based on these isotope ratios, the research team identified three stages in the formation process of the Pilbara Craton supercontinent.
The first stage involved the partial melting of the Earth’s crust due to meteor impacts, heating the crust upon collision. The second stage was the reformation and stabilization of the core of the ancient crust, while the third stage involved the melting and formation of granite.
Subsequently, the core itself was affected and restructured by meteors, and this changing composition would develop into continents, forming the land on which humanity now resides.
These findings align with previously proposed models regarding the formation of massive impact craters across Earth. The planet was heavily bombarded, but only impacts from the largest meteors could create landmasses.
This research has just been published in the scientific journal Nature.
