Around 3 billion years ago, Earths crust ballooned during a massive growth spurt, geoscientists have found.

At that time, just 1.5 billion years after Earth formed, the mantle — the layer of silicate rock between the crust and the outer core that was more active in the past — heated up, causing magma from that layer to ooze into fragments of older crust above it. Those fragments acted as “seeds” for the growth of modern-day continents.