Plate tectonics may have got a very early start

摘要

EARTH'S tectonic plates may have begun moving 4 billion years ago, almost a billion years earlier than thought, according to an analysis of ancient rocks. The claim has earned a mixed response from geologists. Many argue that Earth was too hot at the time for plate tectonics in its modern form. Today, Earth's crust is divided into several dozen rigid plates that move slowly. Where two plates meet, one can be forced under the other and destroyed inside the planet, a process called subduction.