Heavy potassium in ancient lavas reveals Earth recycled its surface 3.6 billion years ago

Long before life had found its footing, Earth was already practicing the art of renewal — folding its own surface back into its depths. Analysis of 3.6-billion-year-old komatiite lavas from South Africa and Canada reveals that seawater-soaked crust was being drawn into the planet's mantle far earlier than science had supposed, suggesting the recycling engine that keeps Earth habitable may have awakened within its first billion years. The discovery, led by doctoral researcher Zheng-Yu Long at the Paris Institute of Earth Physics, does not rewrite the story of plate tectonics so much as push its