Sabiia Seb
        Busca avançada

Botão Atualizar

Botão Atualizar

Registro completo
Provedor de dados:  ArchiMer
País:  France
Título:  Oxygen isotopic evidence for accretion of Earth's water before a high-energy Moon-forming giant impact
Autores:  Greenwood, Richard C.
Barrat, Jean-alix
Miller, Martin F.
Anand, Mahesh
Dauphas, Nicolas
Franchi, Ian A.
Sillard, Patrick
Starkey, Natalie A.
Data:  2018-03
Ano:  2018
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.
Tipo:  Text
Idioma:  Inglês

Editor:  Amer Assoc Advancement Science
Formato:  application/pdf
Fonte:  Science Advances (2375-2548) (Amer Assoc Advancement Science), 2018-03 , Vol. 4 , N. 3 , P. eaao5928 (9p.)
Direitos:  info:eu-repo/semantics/openAccess

restricted use

Empresa Brasileira de Pesquisa Agropecuária - Embrapa
Todos os direitos reservados, conforme Lei n° 9.610
Política de Privacidade
Área restrita

Parque Estação Biológica - PqEB s/n°
Brasília, DF - Brasil - CEP 70770-901
Fone: (61) 3448-4433 - Fax: (61) 3448-4890 / 3448-4891 SAC:

Valid HTML 4.01 Transitional