Now, we have new evidence to suggest that giant meteorite impacts played a significant role.
Known as the Pilbara Craton, it is the best-preserved chunk of crust on the planet… and the zircon crystals within it contain evidence of ancient meteorite impacts before the continents broke apart.
"Studying the composition of oxygen isotopes in these zircon crystals revealed a 'top-down' process starting with the melting of rocks near the surface and progressing deeper, consistent with the geological effect of giant meteorite impacts," explained geologist Tim Johnson of Curtin University in Australia.
"Our research provides the first solid evidence that the processes that ultimately formed the continents began with giant meteorite impacts, similar to those responsible for the extinction of the dinosaurs, but which occurred billions of years earlier.".
The first stage is the formation of a large proportion of zircons consistent with partial melting of the crust.