| Registro completo |
| Provedor de dados: |
ArchiMer
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| País: |
France
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| Título: |
Oxygen isotopic evidence for accretion of Earth's water before a high-energy Moon-forming giant impact
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| Autores: |
Greenwood, Richard C.
Barrat, Jean-alix
Miller, Martin F.
Anand, Mahesh
Dauphas, Nicolas
Franchi, Ian A.
Sillard, Patrick
Starkey, Natalie A.
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| Data: |
2018-03
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| Ano: |
2018
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| Resumo: |
The Earth-Moon system likely formed as a result of a collision between two large planetary objects. Debate about their relative masses, the impact energy involved, and the extent of isotopic homogenization continues. We present the results of a high-precision oxygen isotope study of an extensive suite of lunar and terrestrial samples. We demonstrate that lunar rocks and terrestrial basalts show a 3 to 4 ppm (parts per million), statistically resolvable, difference in Delta O-17. Taking aubrite meteorites as a candidate impactor material, we show that the giant impact scenario involved nearly complete mixing between the target and impactor. Alternatively, the degree of similarity between the Delta O-17 values of the impactor and the proto-Earth must have been significantly closer than that between Earth and aubrites. If the Earth-Moon system evolved from an initially highly vaporized and isotopically homogenized state, as indicated by recent dynamical models, then the terrestrial basalt-lunar oxygen isotope difference detected by our study may be a reflection of post-giant impact additions to Earth. On the basis of this assumption, our data indicate that post-giant impact additions to Earth could have contributed between 5 and 30% of Earth's water, depending on global water estimates. Consequently, our data indicate that the bulk of Earth's water was accreted before the giant impact and not later, as often proposed.
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| Tipo: |
Text
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| Idioma: |
Inglês
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| Identificador: |
https://archimer.ifremer.fr/doc/00638/74995/75750.pdf
https://archimer.ifremer.fr/doc/00638/74995/75751.pdf
DOI:10.1126/sciadv.aao5928
https://archimer.ifremer.fr/doc/00638/74995/
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| Editor: |
Amer Assoc Advancement Science
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| Formato: |
application/pdf
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| Fonte: |
Science Advances (2375-2548) (Amer Assoc Advancement Science), 2018-03 , Vol. 4 , N. 3 , P. eaao5928 (9p.)
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| Direitos: |
info:eu-repo/semantics/openAccess
restricted use
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