Space

Earth's Most Abundant Mineral is Called Bridgmanite by Scientists

Catherine Griffin
First Posted: Dec 16, 2014 09:59 AM EST

The Earth's most abundant mineral family finally has a name. Scientists have used an ancient meteorite and high-energy X-rays to find, identify and characterize a mineral that makes up about 38 percent of our planet.

In order to actually determine the makeup of the inner layers of the Earth, scientists need to test materials under extreme pressure and temperatures. For decades, researchers have believed that a dense perovskite structure makes up 38 percent of the Earth's volume, and that the chemical and physical properties of Bridgmanite, the newly named mineral, have a large influence on how elements and heat flow through Earth's mantle. But because this mineral failed to survive the trip to the surface, no one has been able to prove its existence.

That's why scientists turned to other methods-and samples. Shock-compression that occurs in collisions of asteroid bodies in the solar system creates the same hostile conditions of the deep Earth. The shocks of impact occur fast enough to inhibit Bridgmanite breakdown, and part of the debris from these collisions falls to the Earth as meteorites.

In this case, the researchers used non-destructive micro-focused X-rays for diffraction analysis and novel fast-readout area-detector techniques. More specifically, they examined a section of the highly shocked L-chondrite meteorite Tenham, which crashed in Australia in 1879. This allowed them to spot tiny specimens of Bridgmantine.

Before now, Bridgmantine's properties have only been guessed at. The scientists found that it contains an unexpectedly high amount of ferric iron, and contains much more sodium than synthetic samples.

The findings reveal a bit more about the mineral that makes up so much of our planet. This, in turn, may pave the way for future studies that examine deep mantle rocks.

The findings are published in the journal Science.

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