Mineralogy and noble gas isotopes of micrometeorites collected from Antarctic snow Planetary Science
We have investigated seven micrometeorites (MMs) from Antarctic snow collected in 2003 and 2010 by means of electron microscopy, X-ray diffraction, micro-Raman spectroscopy, transmission electron microscopy (TEM) observation, and noble-gas isotope analysis. Isotopic ratios of He and Ne indicate that...
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ftkyotouniv:oai:repository.kulib.kyoto-u.ac.jp:2433/212437 2023-05-15T14:01:54+02:00 Mineralogy and noble gas isotopes of micrometeorites collected from Antarctic snow Planetary Science Okazaki, Ryuji Noguchi, Takaaki Tsujimoto, Shin-Ichi Tobimatsu, Yu Nakamura, Tomoki Ebihara, Mitsuru Itoh, Shoichi Nagahara, Hiroko Tachibana, Shogo Terada, Kentaro Yabuta, Hikaru 伊藤, 正一 2015-06-17 application/pdf http://hdl.handle.net/2433/212437 eng eng SpringerOpen 10.1186/s40623-015-0261-8 1880-5981 http://hdl.handle.net/2433/212437 Earth, Planets and Space 67 90 © 2015 Okazaki et al. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. CC-BY Antarctic micrometeorites Noble gas Transmission electron microscopy Atmospheric entry heating Solar energetic particles Journal Article 2015 ftkyotouniv 2018-08-30T23:15:41Z We have investigated seven micrometeorites (MMs) from Antarctic snow collected in 2003 and 2010 by means of electron microscopy, X-ray diffraction, micro-Raman spectroscopy, transmission electron microscopy (TEM) observation, and noble-gas isotope analysis. Isotopic ratios of He and Ne indicate that the noble gases in these MMs are mostly of solar wind (SW). Based on the release patterns of SW [4]He, which should reflect the degree of heating during atmospheric entry, the seven MMs were classified into three types including two least heated, three moderately heated, and two severely heated MMs. The heating degrees are well correlated to their mineralogical features determined by TEM observation. One of the least heated MMs is composed of phyllosilicates, whereas the other consists of anhydrous minerals within which solar flare tracks were observed. The two severely heated MMs show clear evidence of atmospheric heating such as partial melt of the uppermost surface layer in one and abundant patches of dendritic magnetite and Si-rich glass within an olivine grain in the other. It is noteworthy that a moderately heated MM composed of a single crystal of olivine has a [3]He/[4]He ratio of 8.44 × 10[−4], which is higher than the SW value of 4.64 × 10[−4], but does not show a cosmogenic [21]Ne signature such as [20]Ne/[21]Ne/[22]Ne = 12.83/0.0284/1. The isotopic compositions of He and Ne in this sample cannot be explained by mixing of a galactic cosmic ray (GCR)-produced component and SW gases. The high [3]He/[4]He ratio without cosmogenic [21]Ne signature likely indicates the presence of a [3]He-enriched component derived from solar energetic particles. Article in Journal/Newspaper Antarc* Antarctic Kyoto University Research Information Repository (KURENAI) Antarctic |
institution |
Open Polar |
collection |
Kyoto University Research Information Repository (KURENAI) |
op_collection_id |
ftkyotouniv |
language |
English |
topic |
Antarctic micrometeorites Noble gas Transmission electron microscopy Atmospheric entry heating Solar energetic particles |
spellingShingle |
Antarctic micrometeorites Noble gas Transmission electron microscopy Atmospheric entry heating Solar energetic particles Okazaki, Ryuji Noguchi, Takaaki Tsujimoto, Shin-Ichi Tobimatsu, Yu Nakamura, Tomoki Ebihara, Mitsuru Itoh, Shoichi Nagahara, Hiroko Tachibana, Shogo Terada, Kentaro Yabuta, Hikaru Mineralogy and noble gas isotopes of micrometeorites collected from Antarctic snow Planetary Science |
topic_facet |
Antarctic micrometeorites Noble gas Transmission electron microscopy Atmospheric entry heating Solar energetic particles |
description |
We have investigated seven micrometeorites (MMs) from Antarctic snow collected in 2003 and 2010 by means of electron microscopy, X-ray diffraction, micro-Raman spectroscopy, transmission electron microscopy (TEM) observation, and noble-gas isotope analysis. Isotopic ratios of He and Ne indicate that the noble gases in these MMs are mostly of solar wind (SW). Based on the release patterns of SW [4]He, which should reflect the degree of heating during atmospheric entry, the seven MMs were classified into three types including two least heated, three moderately heated, and two severely heated MMs. The heating degrees are well correlated to their mineralogical features determined by TEM observation. One of the least heated MMs is composed of phyllosilicates, whereas the other consists of anhydrous minerals within which solar flare tracks were observed. The two severely heated MMs show clear evidence of atmospheric heating such as partial melt of the uppermost surface layer in one and abundant patches of dendritic magnetite and Si-rich glass within an olivine grain in the other. It is noteworthy that a moderately heated MM composed of a single crystal of olivine has a [3]He/[4]He ratio of 8.44 × 10[−4], which is higher than the SW value of 4.64 × 10[−4], but does not show a cosmogenic [21]Ne signature such as [20]Ne/[21]Ne/[22]Ne = 12.83/0.0284/1. The isotopic compositions of He and Ne in this sample cannot be explained by mixing of a galactic cosmic ray (GCR)-produced component and SW gases. The high [3]He/[4]He ratio without cosmogenic [21]Ne signature likely indicates the presence of a [3]He-enriched component derived from solar energetic particles. |
author2 |
伊藤, 正一 |
format |
Article in Journal/Newspaper |
author |
Okazaki, Ryuji Noguchi, Takaaki Tsujimoto, Shin-Ichi Tobimatsu, Yu Nakamura, Tomoki Ebihara, Mitsuru Itoh, Shoichi Nagahara, Hiroko Tachibana, Shogo Terada, Kentaro Yabuta, Hikaru |
author_facet |
Okazaki, Ryuji Noguchi, Takaaki Tsujimoto, Shin-Ichi Tobimatsu, Yu Nakamura, Tomoki Ebihara, Mitsuru Itoh, Shoichi Nagahara, Hiroko Tachibana, Shogo Terada, Kentaro Yabuta, Hikaru |
author_sort |
Okazaki, Ryuji |
title |
Mineralogy and noble gas isotopes of micrometeorites collected from Antarctic snow Planetary Science |
title_short |
Mineralogy and noble gas isotopes of micrometeorites collected from Antarctic snow Planetary Science |
title_full |
Mineralogy and noble gas isotopes of micrometeorites collected from Antarctic snow Planetary Science |
title_fullStr |
Mineralogy and noble gas isotopes of micrometeorites collected from Antarctic snow Planetary Science |
title_full_unstemmed |
Mineralogy and noble gas isotopes of micrometeorites collected from Antarctic snow Planetary Science |
title_sort |
mineralogy and noble gas isotopes of micrometeorites collected from antarctic snow planetary science |
publisher |
SpringerOpen |
publishDate |
2015 |
url |
http://hdl.handle.net/2433/212437 |
geographic |
Antarctic |
geographic_facet |
Antarctic |
genre |
Antarc* Antarctic |
genre_facet |
Antarc* Antarctic |
op_relation |
10.1186/s40623-015-0261-8 1880-5981 http://hdl.handle.net/2433/212437 Earth, Planets and Space 67 90 |
op_rights |
© 2015 Okazaki et al. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. |
op_rightsnorm |
CC-BY |
_version_ |
1766271959515004928 |