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IPFS News Link • Geography

North American Continent as Layer Cake

• arclein
These old floating pieces of the lithosphere, called cratons, apparently stopped growing about 2 billion years ago as the Earth cooled, though within the last 500 million years, and perhaps for as long as 1 billion years, the modern era of plate tectonics has added new margins to the original cratons, slowly expanding the continents.

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