A post-stishovite SiO2 polymorph in the meteorite Shergotty: Implications for impact events

Thomas Sharp, A. El Goresy, B. Wopenka, M. Chen

Research output: Contribution to journalArticlepeer-review

114 Scopus citations


Transmission electron microscopy and electron diffraction show that the martian meteorite Shergotty, a shocked achondrite, contains a dense orthorhombic SiO2 phase similar to post-stishovite SiO2 with the α-PbO2 structure. If an SiO2 mineral exists in Earth's lower mantle, it would probably occur in a post-stishovite SiO2 structure. The presence of such a high-density polymorph in a shocked sample indicates that post-stishovite SiO2 structures may be used as indicators of extreme shock pressures.

Original languageEnglish (US)
Pages (from-to)1511-1513
Number of pages3
Issue number5419
StatePublished - May 28 1999

ASJC Scopus subject areas

  • General


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