Interpreting the production of 26Al in Antarctic meteorites
Large numbers of meteorites have been concentrated at several locations in Antarctica. Glaciological mechanisms of grossly different time scales have been proposed to account for their transport by the ice, and the frequency distribution of the terrestrial ages of these objects has been suggested as...
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ftnasantrs:oai:casi.ntrs.nasa.gov:19870017271 2023-05-15T13:35:11+02:00 Interpreting the production of 26Al in Antarctic meteorites Heydegger, H. R. Unclassified, Unlimited, Publicly available Jun 1, 1987 application/pdf http://hdl.handle.net/2060/19870017271 unknown Document ID: 19870017271 Accession ID: 87N26704 http://hdl.handle.net/2060/19870017271 No Copyright CASI ASTROPHYSICS NASA. Lyndon B.; NASA. Lyndon B. John 1987 ftnasantrs 2015-03-15T06:29:05Z Large numbers of meteorites have been concentrated at several locations in Antarctica. Glaciological mechanisms of grossly different time scales have been proposed to account for their transport by the ice, and the frequency distribution of the terrestrial ages of these objects has been suggested as a means of determining the relevant time scales. The upper limit to the ages of ice in Antarctica which would emerge from such a project is of interest to many other disciplines. After a meteorite reaches the Earth's surface, the specific radioactivity of Al-26 produced by cosmic rays while it was in space decreases because shielding by the Earth's atmosphere reduces further production to a neglible level. Thus, the known half life of this species can be used to determine the object's terrestrial age if the specific radioactivity at time of fall can be determined with reasonable accuracy and precision. The several models utilized for these predictions were based on the limited data available nearly two decades ago. The much larger data base now available was examined using multiple parameter regression analyses. Other/Unknown Material Antarc* Antarctic Antarctica NASA Technical Reports Server (NTRS) Antarctic |
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NASA Technical Reports Server (NTRS) |
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ftnasantrs |
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ASTROPHYSICS |
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ASTROPHYSICS Heydegger, H. R. Interpreting the production of 26Al in Antarctic meteorites |
topic_facet |
ASTROPHYSICS |
description |
Large numbers of meteorites have been concentrated at several locations in Antarctica. Glaciological mechanisms of grossly different time scales have been proposed to account for their transport by the ice, and the frequency distribution of the terrestrial ages of these objects has been suggested as a means of determining the relevant time scales. The upper limit to the ages of ice in Antarctica which would emerge from such a project is of interest to many other disciplines. After a meteorite reaches the Earth's surface, the specific radioactivity of Al-26 produced by cosmic rays while it was in space decreases because shielding by the Earth's atmosphere reduces further production to a neglible level. Thus, the known half life of this species can be used to determine the object's terrestrial age if the specific radioactivity at time of fall can be determined with reasonable accuracy and precision. The several models utilized for these predictions were based on the limited data available nearly two decades ago. The much larger data base now available was examined using multiple parameter regression analyses. |
format |
Other/Unknown Material |
author |
Heydegger, H. R. |
author_facet |
Heydegger, H. R. |
author_sort |
Heydegger, H. R. |
title |
Interpreting the production of 26Al in Antarctic meteorites |
title_short |
Interpreting the production of 26Al in Antarctic meteorites |
title_full |
Interpreting the production of 26Al in Antarctic meteorites |
title_fullStr |
Interpreting the production of 26Al in Antarctic meteorites |
title_full_unstemmed |
Interpreting the production of 26Al in Antarctic meteorites |
title_sort |
interpreting the production of 26al in antarctic meteorites |
publishDate |
1987 |
url |
http://hdl.handle.net/2060/19870017271 |
op_coverage |
Unclassified, Unlimited, Publicly available |
geographic |
Antarctic |
geographic_facet |
Antarctic |
genre |
Antarc* Antarctic Antarctica |
genre_facet |
Antarc* Antarctic Antarctica |
op_source |
CASI |
op_relation |
Document ID: 19870017271 Accession ID: 87N26704 http://hdl.handle.net/2060/19870017271 |
op_rights |
No Copyright |
_version_ |
1766062105269633024 |