Report

A Post-Stishovite SiO2 Polymorph in the Meteorite Shergotty: Implications for Impact Events

Science  28 May 1999:
Vol. 284, Issue 5419, pp. 1511-1513
DOI: 10.1126/science.284.5419.1511

You are currently viewing the abstract.

View Full Text

Via your Institution

Log in through your institution

Log in through your institution


Abstract

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.

  • Present address: Max-Planck-Institut für Chemie, J.-Becher-Weg 27, 55128 Mainz, Germany.

View Full Text

Related Content