Geologists May Have Just Discovered A New Layer Of Earth’s Mantle
Have geologists just discovered a new layer of Earth’s interior?
A new study suggests that a previously unknown rocky layer may be lurking about 930 miles beneath our feet — and evidence suggests that it’s significantly stiffer than similar layers, which could help explain earthquakes and volcanic eruptions.
“The Earth has many layers, like an onion,” study co-author Dr. Lowell Miyagi, an assistant professor of geology and geophysics at the University of Utah, said in a written statement. “Most layers are defined by the minerals that are present. Essentially, we have discovered a new layer in the Earth. This layer isn’t defined by the minerals present, but by the strength of these minerals.”
The pressure is on. For the study, the researchers used a device known as a diamond anvil to simulate how the mineral ferropericlase reacts to high pressure. Ferropericlase is abundant in the Earth’s mantle, the layer that’s sandwiched between our planet’s core and the thin crust on which we live.
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Miyagi holding a press that houses the diamond anvil, in which minerals can be squeezed at pressures akin to those deep within the Earth.
What did the researchers find? The stiffness, or viscosity, of the mineral increased threefold by the time it was subjected to pressure equal to what’s found in the lower mantle (930 miles below Earth’s surface) compared to the pressure at the boundary of the upper and lower mantle (410 miles beneath the surface). When the researchers mixed ferropericlase with bridgmanite (another mineral found in the lower mantle), the simulation showed that its stiffness at 930 miles was 300 times greater than at 410 miles.
The viscosity increase came as a surprise, since it was previously thought that viscosity varied only slightly at different pressures and temperatures in the planet’s interior. —> Read More