2010年1月
Plagioclase breakdown as an indicator for shock conditions of meteorites
NATURE GEOSCIENCE
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- 巻
- 3
- 号
- 1
- 開始ページ
- 41
- 終了ページ
- 45
- 記述言語
- 英語
- 掲載種別
- 研究論文(学術雑誌)
- DOI
- 10.1038/NGEO704
- 出版者・発行元
- NATURE PUBLISHING GROUP
Shocked meteorites that were formed when their parent body underwent shock metamorphism often contain the mineral plagioclase either in an amorphous form or in its high-pressure phase. The peak pressures in shock metamorphism can be constrained by shock-recovery experiments that determine the amorphization pressures of plagioclase(1-3). However, in these experiments temperatures have been unrealistically low and timescales much shorter than those in natural events. Here we present in situ X-ray diffraction measurements of two kinds of plagioclase feldspar in conditions of increasing pressures and temperatures. We find that the amorphization pressure of plagioclase decreases with increasing temperature, suggesting that previous studies overestimated this parameter(1-3). We also found that the mineral jadeite forms first from amorphous plagioclase, whereas the nucleation of other minerals such as stishovite or garnet is significantly delayed. The occurrence of jadeite in shocked meteorites that do not contain stishovite(4-8) can therefore be explained as a result of the crystallization kinetics. We conclude that the study of plagioclase breakdown can constrain the pressure-temperature-time history of shock events, and thus help to reconstruct the collisional history of asteroids in the early Solar System.
- リンク情報
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- DOI
- https://doi.org/10.1038/NGEO704
- Web of Science
- https://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=JSTA_CEL&SrcApp=J_Gate_JST&DestLinkType=FullRecord&KeyUT=WOS:000272976200015&DestApp=WOS_CPL
- URL
- https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=73449109516&origin=inward
- ID情報
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- DOI : 10.1038/NGEO704
- ISSN : 1752-0894
- SCOPUS ID : 73449109516
- Web of Science ID : WOS:000272976200015