Hawaii’s volcanoes pose a problem for traditional theories of plate tectonics (Richard A. Cooke III/Getty Images)
“A LOT of people thinks that the devil has come here. Some thinks that this is the beginning of the world coming to a end.”
To George Heinrich Crist, who wrote this on 23 January 1812, the series of earthquakes that had just ripped through the Mississippi river valley were as inexplicable as they were deadly. Two centuries on and we are no closer to an understanding. According to our established theory of Earth’s tectonic activity, the US Midwest is just not the sort of place such tremors should occur.
That’s not the only thing we are struggling to explain. Submerged fossil landscapes off the west coast of Scotland, undersea volcanoes in the south Pacific, the bulging dome of land that is the interior of southern Africa: all over the world we see features that plate tectonics alone is hard pressed to describe.
So what can? If a new body of research is to be believed, the full answer lies far deeper in our planet. If so, it could shake up geology as fundamentally as the acceptance of plate tectonics did half a century ago.
The central idea of plate tectonics is that Earth’s uppermost layers – a band of rock between 60 and 250 kilometres thick known as the lithosphere – is divided into a mosaic of rigid pieces that float and move atop the viscous mantle immediately beneath. The theory surfaced in 1912, when German geophysicist Alfred Wegener argued on the basis of fossil distributions that today’s continents formed from a single supercontinent, which came to be called…
