Share it! Science : Introducing Bridgmanite, Earth's Most Abundant Mineral

Introducing Bridgmanite, Earth's Most Abundant Mineral

(image credit: NASA Goddard Space Flight Center)
     Why is it that a mineral that makes up 70% of Earth's mantle, or 38% of Earth's total volume can go nameless for half a century? According to the International Mineralogical Association, a mineral cannot be officially named until it can be examined through direct evidence, or first hand. Scientists have known about this mineral for a long time, but as it is more or less trapped anywhere from 660km-2,900km below the Earth's surface they have not been able to obtain an intact sample to thoroughly study. In order to find a sample to study more carefully and also officially name, researchers have focused their attention on meteorites and their impact sites. After decades of searching, scientists were able to find an appropriate sample in a meteorite that crashed into Australia in the late 1800's. Our most common mineral has now been given the name bridgmanite, in honor of Percy Bridgman, a pioneer in high-pressure physics.
     U.S. Geologists published their paper in Science. But how did they know to focus their search for this unobtainable mineral on meteorite crash sites? Bridgmanite, or perovskite as it was formally known, forms under extremely high-pressure conditions. The impact of a meteorite was thought to be enough to create the amount of pressure needed to form the mineral. Earlier research of meteorites had been unsuccessful because of the methods used to look for the perovskite in the meteorite would destroy it before they could study it. This recent attempt used a combination of a micro-focused X-ray beam and electron microscopy. This discovery not only finally gives the mineral a name, but could help us better understand the structure of Earth, and might shed some more light on how our universe was formed.

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