The Earth’s interior is teeming with dead plates

Enlarge (credit: Atlas of the Underworld)

Last week, scientists released a monumental interactive catalog that tracks 94 ancient tectonic plates lurking deep within Earth’s mantle, a resource they’re calling an “Atlas of the Underworld.”

Although scientists have known for decades that tectonic plates plunge into the Earth’s interior at subduction zones, until recently, those plates disappeared off the geological map once they stopped generating earthquakes, which happens after they’re around 670km below the surface. In the last few years, seismic tomography, which uses waves from earthquakes to make images of the planet’s interior, has restored their visibility. It has revealed subducted plates sinking in the mantle all the way down to the core-mantle boundary, 2,900km below Earth’s surface.

Now, Dutch scientists Douwe van der Meer, Douwe van Hinsbergen, and Wim Spakman of Utrecht University have catalogued 94 separate pieces of ancient tectonic plates, called “slabs,” in the mantle, linking them to dates where geological events happened while they were on the surface. Some subducted almost 300 million years ago, while others can be traced to active faults, such as those along the western coast of the Americas.