Vast amounts of sediment eroded from Earth’s continents were necessary to lubricate the wheel of plate tectonics, scientists propose. The idea offers a new angle on long-standing riddles about the origin and evolution of the planet’s global surface recycling system, one that is unique in the solar system.
Earth’s interior holds a lot of heat, even 4.6 billion years after the planet’s formation. For the first 1 billion to 1.5 billion years of Earth’s history, the planet’s insides were still too hot for the lithosphere to cool and thicken (SN Online: 9/21/17). That’s one necessary ingredient for modern plate tectonics, the ongoing collisions and separations of large “plates” of lithosphere, the jigsaw puzzle pieces that make up the hard outer shell of the planet.