Plate tectonics may have started a billion years earlier than thought

By Michael Marshall

The mountains of central Japan have distinctive geological chemistry

Moonies World Photography / Alamy

Plate tectonics began 4 billion years ago, almost a billion years earlier than expected, according to a new analysis of ancient rocks.

The claim has earned a mixed answer from other geologists. Many argue that the earth was too hot for plate tectonics in its modern form at the time.

Today the earth’s crust is divided into several dozen rigid plates that move over millions of years. Where two plates meet, one can be forced under the other and destroyed inside the planet, a …