Cosmogenic records in Antarctic meteorites
Aliquot samples of 29 Antarctic L and H chondrites are analyzed for their nuclear track records and Mn-53 activities. The track density in the analyzed samples ranges from 10 to the 4th to approximately 6 x 10 to the 6th per sq cm. A significant finding is the observation of track-rich grains in a s...
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ftnasantrs:oai:casi.ntrs.nasa.gov:19830061931 2023-05-15T13:35:32+02:00 Cosmogenic records in Antarctic meteorites Goswami, J. N. Nishiizumi, K. Unclassified, Unlimited, Publicly available Jul 1, 1983 http://ntrs.nasa.gov/search.jsp?R=19830061931 unknown http://ntrs.nasa.gov/search.jsp?R=19830061931 Accession ID: 83A43149 Copyright Other Sources 91 Earth and Planetary Science Letters; 64; 1, Ju; July 198 1983 ftnasantrs 2012-02-15T15:31:57Z Aliquot samples of 29 Antarctic L and H chondrites are analyzed for their nuclear track records and Mn-53 activities. The track density in the analyzed samples ranges from 10 to the 4th to approximately 6 x 10 to the 6th per sq cm. A significant finding is the observation of track-rich grains in a set of four L3 chondrites (ALHA 77215, 77216, 77217, and 77252), suspected of belonging to the same fall based on petrographic observations. An additional sample, ALHA 78105, an L6 chondrite, also has track-rich grains. Mn-53 activity is at near saturation level in approximately 65 percent of the analyzed samples, suggesting exposure ages of greater than 10 m.y. in these cases. Very few H chondrites from the 7-m.y. exposure age peak are apparently sampled among the ones investigated in this study. Approximately 6 percent and 4 percent, respectively, of the Antarctic H and L chondrites analyzed thus far for their cosmogenic records have precompaction irradiation features. A combined analysis of Mn-53 and nuclear track data makes it possible to confirm or rule out the proposed pairing of several sets of Antarctic meteorites and to estimate the preatmospheric sizes of some of these meteorites. The results suggest that most of the small Antarctic meteorites (less than 1 kg) have suffered high (greater than 95 percent) ablation mass-loss. Other/Unknown Material Antarc* Antarctic NASA Technical Reports Server (NTRS) Antarctic The Antarctic |
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NASA Technical Reports Server (NTRS) |
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ftnasantrs |
language |
unknown |
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91 |
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91 Goswami, J. N. Nishiizumi, K. Cosmogenic records in Antarctic meteorites |
topic_facet |
91 |
description |
Aliquot samples of 29 Antarctic L and H chondrites are analyzed for their nuclear track records and Mn-53 activities. The track density in the analyzed samples ranges from 10 to the 4th to approximately 6 x 10 to the 6th per sq cm. A significant finding is the observation of track-rich grains in a set of four L3 chondrites (ALHA 77215, 77216, 77217, and 77252), suspected of belonging to the same fall based on petrographic observations. An additional sample, ALHA 78105, an L6 chondrite, also has track-rich grains. Mn-53 activity is at near saturation level in approximately 65 percent of the analyzed samples, suggesting exposure ages of greater than 10 m.y. in these cases. Very few H chondrites from the 7-m.y. exposure age peak are apparently sampled among the ones investigated in this study. Approximately 6 percent and 4 percent, respectively, of the Antarctic H and L chondrites analyzed thus far for their cosmogenic records have precompaction irradiation features. A combined analysis of Mn-53 and nuclear track data makes it possible to confirm or rule out the proposed pairing of several sets of Antarctic meteorites and to estimate the preatmospheric sizes of some of these meteorites. The results suggest that most of the small Antarctic meteorites (less than 1 kg) have suffered high (greater than 95 percent) ablation mass-loss. |
format |
Other/Unknown Material |
author |
Goswami, J. N. Nishiizumi, K. |
author_facet |
Goswami, J. N. Nishiizumi, K. |
author_sort |
Goswami, J. N. |
title |
Cosmogenic records in Antarctic meteorites |
title_short |
Cosmogenic records in Antarctic meteorites |
title_full |
Cosmogenic records in Antarctic meteorites |
title_fullStr |
Cosmogenic records in Antarctic meteorites |
title_full_unstemmed |
Cosmogenic records in Antarctic meteorites |
title_sort |
cosmogenic records in antarctic meteorites |
publishDate |
1983 |
url |
http://ntrs.nasa.gov/search.jsp?R=19830061931 |
op_coverage |
Unclassified, Unlimited, Publicly available |
geographic |
Antarctic The Antarctic |
geographic_facet |
Antarctic The Antarctic |
genre |
Antarc* Antarctic |
genre_facet |
Antarc* Antarctic |
op_source |
Other Sources |
op_relation |
http://ntrs.nasa.gov/search.jsp?R=19830061931 Accession ID: 83A43149 |
op_rights |
Copyright |
_version_ |
1766066907325136896 |