A monoclinic pst-stishovite polymorph of silica in the Shergotty meteorite

Ahmed El Goresy, Leonid Dubrovinsky, Thomas Sharp, Surendra K. Saxena, Ming Chen

Research output: Contribution to journalArticlepeer-review

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A post-stishovite phase of silica was identified in the Shergotty meteorite by x-ray diffraction and field emission scanning electron microscopy. The diffraction pattern revealed a monoclinic lattice, similar to the baddeleyite-structured polymorph with the cell parameters a = 4.375(1) angstroms, b = 4.584(1) angstroms, c = 4.708(1) angstroms, β= 99.97(3), π = 4.30(2) grams per cubic centimeter, where the numbers in parentheses are the maximum deviations. Transmission electron microscopy investigations indicate the presence of the α-lead dioxide-like polymorph, stishovite, and secondary cristobalite in the same silica grain. The mixture of high-density polymorphs suggests that several post-stishovite phases were formed during the shock event on the Shergotty parent body.

Original languageEnglish (US)
Pages (from-to)1632-1634
Number of pages3
Issue number5471
StatePublished - Jun 2 2000

ASJC Scopus subject areas

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