Argon Analyses of Lherzolic Shergottites Y984028 and Y000097
Antarctic Martian meteorites Yamato (Y) 984028 and Y000027/47/97 have similar textures, mineralogy, chemistry, and isotopic composition and are possibly paired. We analyzed the argon isotopic composition of Y984028 whole rock (WR) and pyroxene mineral separates (Px) in order to evaluate their trappe...
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ftnasantrs:oai:casi.ntrs.nasa.gov:20100026405 2023-05-15T13:43:16+02:00 Argon Analyses of Lherzolic Shergottites Y984028 and Y000097 Park, J. Misawa, K. Shih, C.-Y. Bogard, D. D. Garrison, D. H. Nyquist, L. E. Mikouchi, T. Unclassified, Unlimited, Publicly available June 08, 2010 application/pdf http://hdl.handle.net/2060/20100026405 unknown Document ID: 20100026405 http://hdl.handle.net/2060/20100026405 Copyright, Distribution as joint owner in the copyright CASI Lunar and Planetary Science and Exploration M10-0707 33rd Symposium on Antarctic Meteorites; 8-10 Jun. 2010; Tokyo; Japan 2010 ftnasantrs 2019-07-21T01:13:12Z Antarctic Martian meteorites Yamato (Y) 984028 and Y000027/47/97 have similar textures, mineralogy, chemistry, and isotopic composition and are possibly paired. We analyzed the argon isotopic composition of Y984028 whole rock (WR) and pyroxene mineral separates (Px) in order to evaluate their trapped Ar components and compare with Y000097 Ar data. WR and Px yield an apparent Ar-39-Ar-40 age spectra of roughly 2 Ga, much older than the crystallization age determined by other isotopic techniques. Sm-Nd and Rb-Sr ages for Y984028 are approximately 170 Ma. This discrepancy is likely the byproduct of several coexisting Ar components, such as radiogenic 40Ar*, cosmogenic Ar, and trapped Ar from the multiple minerals, as well as multiple source origins. Similarly, the reported Ar-39-Ar-40 age of Y000097 is approximately 260 Ma with a Rb-Sr age of 147+/- 28 Ma and a Sm-Nd age of 152 +/- 13 Ma [4]. Apparently Ar-Ar ages of both Y984028 and Y000097 show trapped Ar components. Stepwise temperature extractions of Ar from Y984028 Px show several Arcomponents released at different temperatures. For example, intermediate temperature data (800-1100 C) are nominally consistent with the Sm-Nd and Rb-Sr radiometric ages (approximately 170 Ma) with an approximately Martian atmosphere trapped Ar composition with a Ar-40-Ar-36 ratio of approximately 1800. Based on K/Ca distribution, we know that Ar-39 at both lower and intermediate temperatures is primarily derived from plagioclase and olivine. Argon released during higher temperature extractions (1200-1500 C), however, differs significantly. The thermal profile of argon released from Martian meteorites is complicated by multiple sources, such as Martian atmosphere, Martian mantle, inherited Ar, terrestrial atmosphere, cosmogenic Ar. Obviously, Ar release at higher temperatures from Px should contain little terrestrial atmospheric component. Likewise, Xe-129/Xe-132 from high temperature extractions (1200-1800 C) gives a value above that of terrestrial Xe ratio of 0.98. The most plausible explanation of the high temperature argon data is that it contains a Martian mantle Ar-40 component as well as excess Ar-40 assimilated from inherited magma. Other/Unknown Material Antarc* Antarctic NASA Technical Reports Server (NTRS) Antarctic Yamato ENVELOPE(35.583,35.583,-71.417,-71.417) |
institution |
Open Polar |
collection |
NASA Technical Reports Server (NTRS) |
op_collection_id |
ftnasantrs |
language |
unknown |
topic |
Lunar and Planetary Science and Exploration |
spellingShingle |
Lunar and Planetary Science and Exploration Park, J. Misawa, K. Shih, C.-Y. Bogard, D. D. Garrison, D. H. Nyquist, L. E. Mikouchi, T. Argon Analyses of Lherzolic Shergottites Y984028 and Y000097 |
topic_facet |
Lunar and Planetary Science and Exploration |
description |
Antarctic Martian meteorites Yamato (Y) 984028 and Y000027/47/97 have similar textures, mineralogy, chemistry, and isotopic composition and are possibly paired. We analyzed the argon isotopic composition of Y984028 whole rock (WR) and pyroxene mineral separates (Px) in order to evaluate their trapped Ar components and compare with Y000097 Ar data. WR and Px yield an apparent Ar-39-Ar-40 age spectra of roughly 2 Ga, much older than the crystallization age determined by other isotopic techniques. Sm-Nd and Rb-Sr ages for Y984028 are approximately 170 Ma. This discrepancy is likely the byproduct of several coexisting Ar components, such as radiogenic 40Ar*, cosmogenic Ar, and trapped Ar from the multiple minerals, as well as multiple source origins. Similarly, the reported Ar-39-Ar-40 age of Y000097 is approximately 260 Ma with a Rb-Sr age of 147+/- 28 Ma and a Sm-Nd age of 152 +/- 13 Ma [4]. Apparently Ar-Ar ages of both Y984028 and Y000097 show trapped Ar components. Stepwise temperature extractions of Ar from Y984028 Px show several Arcomponents released at different temperatures. For example, intermediate temperature data (800-1100 C) are nominally consistent with the Sm-Nd and Rb-Sr radiometric ages (approximately 170 Ma) with an approximately Martian atmosphere trapped Ar composition with a Ar-40-Ar-36 ratio of approximately 1800. Based on K/Ca distribution, we know that Ar-39 at both lower and intermediate temperatures is primarily derived from plagioclase and olivine. Argon released during higher temperature extractions (1200-1500 C), however, differs significantly. The thermal profile of argon released from Martian meteorites is complicated by multiple sources, such as Martian atmosphere, Martian mantle, inherited Ar, terrestrial atmosphere, cosmogenic Ar. Obviously, Ar release at higher temperatures from Px should contain little terrestrial atmospheric component. Likewise, Xe-129/Xe-132 from high temperature extractions (1200-1800 C) gives a value above that of terrestrial Xe ratio of 0.98. The most plausible explanation of the high temperature argon data is that it contains a Martian mantle Ar-40 component as well as excess Ar-40 assimilated from inherited magma. |
format |
Other/Unknown Material |
author |
Park, J. Misawa, K. Shih, C.-Y. Bogard, D. D. Garrison, D. H. Nyquist, L. E. Mikouchi, T. |
author_facet |
Park, J. Misawa, K. Shih, C.-Y. Bogard, D. D. Garrison, D. H. Nyquist, L. E. Mikouchi, T. |
author_sort |
Park, J. |
title |
Argon Analyses of Lherzolic Shergottites Y984028 and Y000097 |
title_short |
Argon Analyses of Lherzolic Shergottites Y984028 and Y000097 |
title_full |
Argon Analyses of Lherzolic Shergottites Y984028 and Y000097 |
title_fullStr |
Argon Analyses of Lherzolic Shergottites Y984028 and Y000097 |
title_full_unstemmed |
Argon Analyses of Lherzolic Shergottites Y984028 and Y000097 |
title_sort |
argon analyses of lherzolic shergottites y984028 and y000097 |
publishDate |
2010 |
url |
http://hdl.handle.net/2060/20100026405 |
op_coverage |
Unclassified, Unlimited, Publicly available |
long_lat |
ENVELOPE(35.583,35.583,-71.417,-71.417) |
geographic |
Antarctic Yamato |
geographic_facet |
Antarctic Yamato |
genre |
Antarc* Antarctic |
genre_facet |
Antarc* Antarctic |
op_source |
CASI |
op_relation |
Document ID: 20100026405 http://hdl.handle.net/2060/20100026405 |
op_rights |
Copyright, Distribution as joint owner in the copyright |
_version_ |
1766186558687281152 |