Scientists Detect Unexpected Structures Near Earth’s Core

University of Maryland geophysicists who analyzed thousands of recordings of echoes from the boundary between Earth’s molten core and the solid mantle layer above it have discovered more widespread, heterogenous structures—areas of unusually dense, hot rock—at the core-mantle boundary than previously known.

The new research, published online today in Science, focused on echoes of seismic waves traveling beneath the Pacific Ocean basin. Their analysis revealed a structure beneath the volcanic Marquesas Islands in the South Pacific and showed that another beneath the Hawaiian Islands is much larger than previously known.

“By looking at thousands of core-mantle boundary echoes at once, instead of focusing on a few at a time, as is usually done, we have gotten a totally new perspective,” said Doyeon Kim, a postdoctoral fellow in the Department of Geology and the lead author of the paper.

Scientists are unsure of the composition of these structures, and previous studies have provided only a limited view of them. Better understanding their shape and extent can help reveal geologic processes deep inside Earth. This knowledge could in turn provide clues to the workings of plate tectonics, which shape the Earth’s surface, and the evolution of our planet.

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