Plate tectonics may be younger than life, Earth’s oldest rocks suggest

As recently as 2.5 billion years ago, seawater was saturated with silicon, making the seabed saturated with heavy isotopes of silicon.  Yet prior to 4.0 billion years ago this was not incorporated into granites, but after 3.8 billion years ago they were.

A study of the world’s oldest rocks provides evidence that plate tectonic-driven recycling may not have begun until several hundred years after the formation of the Earth. The authors admit their findings aren’t conclusive, but if they’re right, they have big implications for what it takes to keep life going. The fact that Earth is … Read more