[R5-03] FIB-TEM observation of co-existing tridymite polymorphs in Moama meteorite | 2022 Annual Meeting of Japan Association of Mineralogical Sciences (JAMS)

2022 Annual Meeting of Japan Association of Mineralogical Sciences (JAMS)

Sep 17 - Sep 19, 2022新潟大学五十嵐キャンパス

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2022 Annual Meeting of Japan Association of Mineralogical Sciences (JAMS)

Sep 17 - Sep 19, 2022新潟大学五十嵐キャンパス

[R5-03]FIB-TEM observation of co-existing tridymite polymorphs in Moama meteorite

*Atsushi Takenouchi¹, Yohei Igami², Akira Miyake², Norimasa Shimobayashi², Takashi Mikouchi³, Haruka Ono³(1. Kyoto Univ. Museum, 2. Kyoto Univ., 3. The Univ. of Tokyo, Univ. Museum)

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Keywords:

Silica,tridymite,TEM,thermal metamorphism

Meteorites sometimes contain various combinations of silica polymorphs, and their variations may relate to their thermal metamorphic history. Here, we report the results of the FIB-TEM study focusing on co-existing tridymite polymorphs in Moama eucrite to clarify the occurrence of the polymorphs. Our observation revealed that monoclinic (Aa) and pseudo-orthorhombic tridymite shared their (001) planes, indicating that they were formed by transformation from a single high-temperature tridymite grain.

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