AUSTRALIA: Today, less than 30% of the landmasses on Earth are comprised of seven continents, with the remaining 70% being submerged in water. The continents evolved over millions of years as a result of plate tectonics and crustal processes, giving the globe its current morphology and geology.
However, a new study claims that the Earth’s history began with a bang and provides the strongest evidence yet that the continents were formed by massive meteorite strikes.
These impacts were frequent in the first billion years of our planet’s almost 4.5 billion-year history. The study supports long-held hypotheses that the continents formed around the locations of meteor impacts.
Researchers examined microscopic zircon crystals found in rocks from Western Australia’s Pilbara Craton. The best-preserved fragment of prehistoric crust on Earth can be found here, along with proof of prehistoric meteor hits.
The oxygen isotope composition of these zircon crystals was investigated by the team, which was led by Curtin University scientists.
The planet’s oldest mineral, zircon, is nearly 4.4 billion years old and occasionally has traces of uranium. They discovered a top-down process that was compatible with the geological effects of massive meteorite impacts, beginning with the melting of rocks close to the surface and moving deeper.
The study “provides the first solid evidence,” according to Dr Tim Johnson of Curtin’s School of Earth and Planetary Sciences, that the processes that ultimately formed the continents began with enormous meteorite impacts billions of years earlier than those that caused the dinosaurs to go extinct.
Given that these landmasses are home to nearly all of the planet’s significant mineral reserves, the majority of its biomass, and all humans, it is imperative to understand how the Earth’s continents formed and are still evolving. The crustal differentiation process, which started with the development of the early landmasses, is what led to the mineral deposits.
Dr Johnson continued, “Last but not least, the continents are home to vital metals like lithium, tin, and nickel, commodities that are crucial to the emerging green technology required to fulfil our duty to combat climate change.”
Researchers also found evidence of patterns comparable to those found in Western Australia in data from other regions of the planet’s old continental crust.