Earth is currently the only planet known to harbor life thanks in large part due to the operation of plate tectonics, which cycles critical biogeochemical elements and maintains a planetary thermostat. Subduction the destructive force of plate tectonics that pushes one plate beneath another is the most telltale sign of plate tectonics' great recycling program.
A new study analyzing fragments of the planet's oldest ancient rocks offers some of the clearest evidence yet that the Earth's crust was pushing and tugging in a way comparable to present plate tectonics at least 3.25 billion years ago.