2015年1月
Late formation of a comet Wild 2 crystalline silicate particle, Pyxie, inferred from Al-Mg chronology of plagioclase
EARTH AND PLANETARY SCIENCE LETTERS
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- 巻
- 410
- 号
- 開始ページ
- 54
- 終了ページ
- 61
- 記述言語
- 英語
- 掲載種別
- 研究論文(学術雑誌)
- DOI
- 10.1016/j.epsl.2014.11.020
- 出版者・発行元
- ELSEVIER SCIENCE BV
We examined the Al-Mg isotope systematics of plagioclase in a FeO-poor ferromagnesian Wild 2 particle (0092,7,81,1,0; named Pyxie) using a similar to 2 mu m spot. Three analyses show average Al-27/Mg-24 ratio of similar to 65 and excess delta Mg-26* value of +0.1 +/- 4.5%0 (2 sigma), indicating no resolvable Mg-26 excess in the particle. The inferred initial (Al-26/Al-27)(0) ratio of plagioclase in Pyxie is estimated as (-0.6 +/- 4.5) x 10(-6) with an upper limit of 4 x 10(-6). The result is very similar to that of the FeO-rich ferromagnesian particle "Iris" (Ogliore et al., 2012). Assuming homogeneous distribution of Al-26 in the early solar system, Pyxie formed at least 2.6 Ma after the oldest Ca-Al-rich inclusions. This minimum formation age is marginally younger than formation ages of most chondrules in type similar to 3.0 chondrites but comparable with those of Mg# < 98 chondrules in CR3 chondrites. Considered in conjunction with similar oxygen isotope ratios between Pyxie (and Iris) and Mg# < 98 chondrules in CR3 chondrites, it is inferred that the ferromagnesian Wild 2 particles and Mg# < 98 chondrules in CR3 chondrites formed late in local disk environments that had similar oxygen isotope ratios and redox states. (C) 2014 Elsevier B.V. All rights reserved.
- リンク情報
- ID情報
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- DOI : 10.1016/j.epsl.2014.11.020
- ISSN : 0012-821X
- eISSN : 1385-013X
- Web of Science ID : WOS:000349196400006