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Discovery of bridgmanite, the most abundant mineral in Earth, in a shocked meteorite

Science  28 Nov 2014:
Vol. 346, Issue 6213, pp. 1100-1102
DOI: 10.1126/science.1259369

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Abstract

Meteorites exposed to high pressures and temperatures during impact-induced shock often contain minerals whose occurrence and stability normally confine them to the deeper portions of Earth’s mantle. One exception has been MgSiO3 in the perovskite structure, which is the most abundant solid phase in Earth. Here we report the discovery of this important phase as a mineral in the Tenham L6 chondrite and approved by the International Mineralogical Association (specimen IMA 2014-017). MgSiO3-perovskite is now called bridgmanite. The associated phase assemblage constrains peak shock conditions to ~ 24 gigapascals and 2300 kelvin. The discovery concludes a half century of efforts to find, identify, and characterize a natural specimen of this important mineral.

A mineral name for mantle perovskite

A rock from outer space finally puts a name to Earth's most abundant mineral, frequently referred to as perovskite. Mineral names are only bestowed on specimens that are found in nature and characterized. Tschauner et al. isolate a magnesium silicate in the perovskite structure, now called bridgmanite, in the Tenham L6 chondrite meteorite (see the Perspective by Sharp). Bridgmanite formed in this meteorite during a high-pressure and -temperature shock event. Other minerals associated with bridgmanite allow the pressure-temperature conditions to be narrowly bound, giving insight into the shock process. The long-sought-after specimen finally puts to rest a confusing nomenclature of this dense deep mantle silicate.

Science, this issue p. 1100; see also p. 1057

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