Ancient rocks reveal when Earth's tectonic engine 'switched on'

Earth's rocks are missing about a billion years. Scientists finally know where it went

It's one of geology's deepest mysteries.

Ancient rocks reveal when Earth's tectonic engine 'switched on'

Scientists have identified a major turning point in Earth's geological history, when the processes shaping the planet's crust changed dramatically and began to resemble the plate tectonics we see today—about 2.5 billion years ago.

A chemical fingerprint in ancient rocks suggests plate tectonics began 2.5 billion years ago

Photo taken during fieldwork in Western Australia, where many of the ancient rocks analysed in this study were collected. Photo by B. WarePlate tectonics is one of the reasons Earth looks so different from its planetary neighbours. The movement of enormous chunks of our planet’s crust builds mountain ranges, triggers earthquakes, shapes our oceans and continents, and helps regulate Earth’s climate and magnetic field over deep time. This process …