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| Titel |
Noble gas signature of the Late Heavy Bombardment in the Earth's atmosphere |
| VerfasserIn |
B. Marty, A. Meibom |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1815-381X
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| Digitales Dokument |
URL |
| Erschienen |
In: eEarth ; 2, no. 2 ; Nr. 2, no. 2 (2007-10-08), S.43-49 |
| Datensatznummer |
250000524
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| Publikation (Nr.) |
 copernicus.org/ee-2-43-2007.pdf |
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| Zusammenfassung |
| The Lunar cratering record is consistent with the occurrence of a late heavy
bombardment (LHB), which marked the end of terrestrial planet accretion 3.8
billion years ago. However, clear evidence of a LHB on Earth has not yet
been identified. Based on a volatile budget of the terrestrial mantle, the
atmosphere and hydrosphere we propose that the LHB did indeed occur on Earth
and that we are breathing its aftermaths. The terrestrial atmosphere and
hydrosphere is enriched in noble gases relative to the abundance of
volatiles in the mantle. This enrichment is consistent with the mass
delivered to Earth during the LHB, as recently proposed from dynamical
modelling (Gomez et al., 2005), if this material comprised a few Kuiper-belt
(cometary) objets (KBOs) mixed in with a population of largely chondritic
(i.e. asteroidal) impactors. The fraction of KBOs necessary to account for
the atmospheric composition is, however, much lower (<1%) than the one
(~50%) inferred from modelling. |
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