The continents of Earth were created by massive meteorite impacts that were particularly frequent during the first billion years of our planet’s four and a half billion-year existence, according to new Curtin study, which has presented the strongest proof to yet.
The hypothesis that the continents were first created at the sites of massive meteorite impacts has been around for a while, but until recently, according to Dr. Tim Johnson of Curtin’s School of Earth and Planetary Sciences, there hasn’t been any strong evidence to back it up.
We uncovered evidence of these massive meteorite impacts by analyzing microscopic crystals of the mineral zircon in rocks from the Pilbara Craton in Western Australia, which represents Earth’s best-preserved relic of ancient crust,” Dr. Johnson stated. These zircon crystals’ oxygen isotope composition analysis indicated a “top-down” mechanism that involved the melting of rocks close to the surface before moving deeper. This technique is compatible with the geological impact caused by massive meteorites. Our discovery offers the first convincing evidence that the mechanisms that eventually gave rise to the continents started with massive meteorite strikes that happened billions of years earlier than those that caused the extinction of the dinosaurs. Given that these landmasses are home to nearly all of the planet’s significant mineral reserves, the bulk of its biomass, and all people, it is essential to understand how the Earth’s continents were formed and are now evolving. Not least, Dr. Johnson noted, “the continents are home to vital metals like lithium, tin, and nickel, commodities that are crucial to the emerging green technologies required to uphold our responsibility to combat climate change.
The creation of the oldest landmasses, of which the Pilbara Craton is only one, led to a process known as crustal differentiation that produced these mineral deposits. Data from other portions of the Earth’s old continental crust seem to reveal patterns resembling those seen in Western Australia. To investigate if, as we anticipate, our model is more broadly applicable, we’d like to test our results on these old rocks.
