Coesite and stishovite in a shocked lunar meteorite, Asuka-881757, and impact events in lunar surface.

E. Ohtani, S. Ozawa, M. Miyahara, Y. Ito, T. Mikouchi, M. Kimura, T. Arai, K. Sato, K. Hiraga

Research output: Contribution to journalArticle

27 Citations (Scopus)

Abstract

Microcrystals of coesite and stishovite were discovered as inclusions in amorphous silica grains in shocked melt pockets of a lunar meteorite Asuka-881757 by micro-Raman spectrometry, scanning electron microscopy, electron back-scatter diffraction, and transmission electron microscopy. These high-pressure polymorphs of SiO(2) in amorphous silica indicate that the meteorite experienced an equilibrium shock-pressure of at least 8-30 GPa. Secondary quartz grains are also observed in separate amorphous silica grains in the meteorite. The estimated age reported by the (39)Ar/(40)Ar chronology indicates that the source basalt of this meteorite was impacted at 3,800 Ma ago, time of lunar cataclysm; i.e., the heavy bombardment in the lunar surface. Observation of coesite and stishovite formed in the lunar breccias suggests that high-pressure impact metamorphism and formation of high-pressure minerals are common phenomena in brecciated lunar surface altered by the heavy meteoritic bombardment.

Original languageEnglish
Pages (from-to)463-466
Number of pages4
JournalProceedings of the National Academy of Sciences of the United States of America
Volume108
Issue number2
DOIs
Publication statusPublished - 2011 Jan 11

ASJC Scopus subject areas

  • General

Fingerprint Dive into the research topics of 'Coesite and stishovite in a shocked lunar meteorite, Asuka-881757, and impact events in lunar surface.'. Together they form a unique fingerprint.

  • Cite this