Oxygen and silicon contents of Earth's core from high pressure metal-silicate partitioning experiments | INSTITUT DE PHYSIQUE DU GLOBE DE PARIS

Twitter

Aller au compte twitter

  Oxygen and silicon contents of Earth's core from high pressure metal-silicate partitioning experiments

Type de publication:

Journal Article

Source:

Earth and Planetary Science Letters, Volume 310, Ticket 3-4 (2011)

ISBN:

0012-821X

Numéro d'accès:

WOS:000298273500026

URL:

http://www.sciencedirect.com/science/article/pii/S0012821X11004596

Mots-clés:

UMR 7154 ; Géophysique expérimentale ; core formation; magma ocean; light elements; high-pressure experiments; metal-silicate partitioning

Résumé:

Oxygen and silicon partitioning between molten metal and silicate melts was measured in samples synthezised in piston-cylinder and multi-anvil presses between 2 and 21 GPa, 2273 and 2873 K, and at oxygen fugacities of 1.5–3.6 log units below the iron–wüstite buffer. Our partitioning data are used together with published data to parameterize the individual effects of pressure, temperature and composition on the partitioning of oxygen and silicon. Results show that the oxygen metal–silicate partition coefficient increases with increasing oxygen fugacity, temperature and pressure, whereas the silicon metal-silicate partition coefficient increases with decreasing oxygen fugacity, increasing temperature and pressure. Silicon and oxygen contents of Earth's core were derived for different core formation models. Considering single-stage core formation at 40 GPa, 3200 K, IW-2, the core would contain 1 to 3.5 wt.% silicon and 0.5 to 2.5 wt.% oxygen. In a continuous core-formation scenario, and depending on the oxidation path, Si core content varies from 1 to 11 wt.%, whereas oxygen content ranges from 0 to 2.5 wt.%. These models show that the oxygen content in the core cannot be significantly higher than 2.5 wt.%. In these compositional models, a range of combined silicon and oxygen concentrations in the core could satisfies the seismologically observed range of outer core density deficits.

Notes:

Times Cited: 1