The continents, the solid blocks of land beneath our feet, weren’t always as strong as they’ve come to be. Now, scientists from Monash University in Australia have devised a new mechanism to explain how the roots of the continents—cratons—came to be. Using numerical models to simulate the conditions of Archean era Earth, the researchers’ findings, published in Nature, show that a strong base for the continents emerged from the melting and stretching of the cratonic lithospheric mantle.

Catherine 'Katie' Cooper

Cratons form the base of continents and hold the title of the oldest existing portion of the lithosphere. They’re extremely thick and began to form up to 3 billion years ago, in the Archean eon. “They’re the secret keepers of the Earth,” said Catherine Cooper, an associate professor of geophysics in the School of the Environment at Washington State University in Pullman. Cooper was not involved in the new research. By studying cratons, scientists might learn how major components of Earth arose and how plate tectonics began. “If you can understand the role of the secret keepers within [Earth], then we can try to answer some of those questions better.”

As scientists gain a firmer grasp of the origins of cratons, they’re better able to understand processes that might be happening within other planets as well as the processes that helped form our own. “[Cratons] have kind of gone along for the ride, picking up all of Earth’s secrets for all this time,” said Cooper. “They’re such an intriguing scientific story.”

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