Ungrouped Iron Meteorites in Antarctica: Origin of Anomalously High Abundance
Eighty-five percent of the iron meteorites collected outside Antarctica are assigned to 13 compositionally and structurally defined groups; the remaining 15 percent are ungrouped. Of the 31 iron meteorites recovered from Antarctica, 39 percent are ungrouped. This major difference in the two sets is...
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craaas:10.1126/science.249.4971.900 2024-09-15T17:42:31+00:00 Ungrouped Iron Meteorites in Antarctica: Origin of Anomalously High Abundance Wasson, John T. 1990 http://dx.doi.org/10.1126/science.249.4971.900 https://www.science.org/doi/pdf/10.1126/science.249.4971.900 en eng American Association for the Advancement of Science (AAAS) Science volume 249, issue 4971, page 900-902 ISSN 0036-8075 1095-9203 journal-article 1990 craaas https://doi.org/10.1126/science.249.4971.900 2024-07-25T04:01:29Z Eighty-five percent of the iron meteorites collected outside Antarctica are assigned to 13 compositionally and structurally defined groups; the remaining 15 percent are ungrouped. Of the 31 iron meteorites recovered from Antarctica, 39 percent are ungrouped. This major difference in the two sets is almost certainly not a stochastic variation, a latitudinal effect, or an effect associated with differences in terrestrial ages. It seems to be related to the median mass of Antarctic irons, which is about 1/100 that of non-Antarctic irons. During impacts on asteroids, smaller fragments tend to be ejected into space at higher velocities than larger fragments, and, on average, small meteoroids have undergone more changes in orbital velocity than large ones. As a result, the set of asteroids that contributes small meteoroids to Earth-crossing orbits is larger than the set that contributes large meteoroids. Most small iron meteorites may escape from the asteroid belt as a result of impact-induced changes in velocity that reduce their perihelia to values less than the aphelion of Mars. Article in Journal/Newspaper Antarc* Antarctic Antarctica AAAS Resource Center (American Association for the Advancement of Science) Science 249 4971 900 902 |
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AAAS Resource Center (American Association for the Advancement of Science) |
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craaas |
language |
English |
description |
Eighty-five percent of the iron meteorites collected outside Antarctica are assigned to 13 compositionally and structurally defined groups; the remaining 15 percent are ungrouped. Of the 31 iron meteorites recovered from Antarctica, 39 percent are ungrouped. This major difference in the two sets is almost certainly not a stochastic variation, a latitudinal effect, or an effect associated with differences in terrestrial ages. It seems to be related to the median mass of Antarctic irons, which is about 1/100 that of non-Antarctic irons. During impacts on asteroids, smaller fragments tend to be ejected into space at higher velocities than larger fragments, and, on average, small meteoroids have undergone more changes in orbital velocity than large ones. As a result, the set of asteroids that contributes small meteoroids to Earth-crossing orbits is larger than the set that contributes large meteoroids. Most small iron meteorites may escape from the asteroid belt as a result of impact-induced changes in velocity that reduce their perihelia to values less than the aphelion of Mars. |
format |
Article in Journal/Newspaper |
author |
Wasson, John T. |
spellingShingle |
Wasson, John T. Ungrouped Iron Meteorites in Antarctica: Origin of Anomalously High Abundance |
author_facet |
Wasson, John T. |
author_sort |
Wasson, John T. |
title |
Ungrouped Iron Meteorites in Antarctica: Origin of Anomalously High Abundance |
title_short |
Ungrouped Iron Meteorites in Antarctica: Origin of Anomalously High Abundance |
title_full |
Ungrouped Iron Meteorites in Antarctica: Origin of Anomalously High Abundance |
title_fullStr |
Ungrouped Iron Meteorites in Antarctica: Origin of Anomalously High Abundance |
title_full_unstemmed |
Ungrouped Iron Meteorites in Antarctica: Origin of Anomalously High Abundance |
title_sort |
ungrouped iron meteorites in antarctica: origin of anomalously high abundance |
publisher |
American Association for the Advancement of Science (AAAS) |
publishDate |
1990 |
url |
http://dx.doi.org/10.1126/science.249.4971.900 https://www.science.org/doi/pdf/10.1126/science.249.4971.900 |
genre |
Antarc* Antarctic Antarctica |
genre_facet |
Antarc* Antarctic Antarctica |
op_source |
Science volume 249, issue 4971, page 900-902 ISSN 0036-8075 1095-9203 |
op_doi |
https://doi.org/10.1126/science.249.4971.900 |
container_title |
Science |
container_volume |
249 |
container_issue |
4971 |
container_start_page |
900 |
op_container_end_page |
902 |
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1810489121765851136 |