The Earth's continents were formed by massive meteorite impacts, according to a new study

The continents of Earth were formed by gigantic meteorite impacts that occurred most frequently during the first billion years of our planet's four-and-a-half billion-year existence, new Curtin research shows.

The theory that the continents formed at the sites of giant meteorite impacts have been around for decades, but until now, little solid evidence was available to support it. Dr. Tim Johnson, from Curtin's School of Earth and Planetary Sciences, tells the Herald.

We found evidence of these giant meteorite impacts by analyzing zircon crystals found in rocks from the Pilbara Craton in Western Australia, which represents Earth's best-preserved remnant of ancient crust,' Dr. Johnson said.

A study of oxygen isotopes in zircon crystals revealed that a 'top-down' process started with the melting of rocks near the surface and continued deeper, consistent with the geological effect caused by giant meteorite impacts.'

With this study, we have provided the first solid evidence that the processes that ultimately formed the continents began with a giant meteorite impact, similar to those responsible for the extinction of the dinosaurs, but billions of years earlier.'

Since Earth's continents host the majority of biomass, all humans, and most of the planet's important minerals, Johnson said understanding the formation and evolution of the planet's continents was crucial.

We need to invest in the continents of the world primarily because they contain critical metals, including lithium, tin, and nickel, which are essential to the development of new green technologies for mitigating climate change,' said Dr. Johnson.

A big part of these mineral deposits can be attributed to the crustal differentiation process, which began when the earliest landmasses were formed, and of which the Pilbara Craton is but one of a multitude of them.

The data relating to ancient continental crust elsewhere on Earth shows similar patterns to those recognized in Western Australia. We wish to test our model on these ancient rocks to see if it is more widely applicable.'

Having studied geoscience, the doctor is now affiliated with one of Curtin's most prominent earth sciences research institutes, The Institute for Geoscience Research.