Study reveals a 'flawed argument' in the debate over when plate tectonics began

Earth’s crust today has a surprisingly similar composition to the planet's first outer shell, or ‘protocrust’, new research finds.

- STEPHANIE PAPPAS

This early rocky shell featured chemical signatures previously thought to occur only in continental crusts made by the process of subduction, in which one tectonic plate slides under another. But plate tectonics isn’t actually required to produce these signatures, according to the new study. These findings are important for the debate over when our planet's plate tectonics began. No one knows exactly when or why the Earth's surface broke into pancake-like slabs that grind and crash against one another, forming mountains and volcanoes and triggering earthquakes.