Volcanoes, diamonds, and blobs: a billion-year history of Earth's interior shows it's more mobile than we thought

Earth’s interior 80 million years ago with hot structures in yellow to red (darker is shallower) and cold structures in blue (darker is deeper). Ömer Bodur/Nature

Deep in the Earth beneath us lie two blobs the size of continents. One is under Africa, the other under the Pacific Ocean.

The blobs have their roots 2,900km below the surface, almost halfway to the centre of the Earth. They are thought to be the birthplace of rising columns of hot rock called “deep mantle plumes” that reach Earth’s surface.