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Metal–silicate partitioning of sulphur, new experimental and thermodynamic constraints on planetary accretion
- Source :
- Earth and Planetary Science Letters, Earth and Planetary Science Letters, Elsevier, 2014, 391, pp.42-54. ⟨10.1016/j.epsl.2014.01.021⟩, Earth and Planetary Science Letters, 2014, 391, pp.42-54. ⟨10.1016/j.epsl.2014.01.021⟩
- Publication Year :
- 2014
- Publisher :
- Elsevier BV, 2014.
-
Abstract
- International audience; Partitioning of sulphur between liquid Fe-rich metals and silicates (View the MathML sourceDSmet/sil) was investigated at temperatures from 1800 °C to 2400 °C, pressures from 2 to 23 GPa and oxygen fugacities from 3.5 to 1.5 log units below the iron–wüstite buffer, using multi-anvil apparatus. The results are combined with previous experimental works to refine a multi-variable thermodynamic model of View the MathML sourceDSmet/sil. Sulphur appears to become more siderophile with increasing pressure and FeO content of the silicate melt, and less siderophile with increasing temperature and with Si, C, O, Fe and Ni contents of the metal. We then modelled the behaviour of sulphur in the course of planetary accretion, using different possible scenarios of mantle dynamics and evolution with time of oxygen fugacity. We investigated three end-member models for metal–silicate segregation of the incoming impactors: (i) the planetary mantle does not mix and is kept chemically stratified, (ii) the magma ocean is continuously mixed chemically, and (iii) both the magma ocean and the solid lower mantle are well mixed.We show that if S is accreted along the accretion, whatever the oxidation path, its distribution between core and mantle can lead to the observed S concentration of the mantle (200±80 ppm200±80 ppm) and to the estimations of S content of the core (from its depletion in the mantle relative to the other elements with the same volatility). In the case of an Earth built with reduced material, to explain the present-day View the MathML source200(±80) ppm S found in the mantle, it is necessary that both the magma ocean and the solid lower mantle mix at each major step of the planetary accretion. S could also be accreted in the last 10 to 20% of Earth's growth and reach its observed present terrestrial abundances if the magma ocean is chemically mixed along the accretion. Consequently, our models show that the S terrestrial abundances do not formally require an S accretion in a late veneer but can be explained by a core–mantle equilibration alone.
- Subjects :
- 010504 meteorology & atmospheric sciences
[SDU.STU.PE]Sciences of the Universe [physics]/Earth Sciences/Petrography
Geochemistry
chemistry.chemical_element
010502 geochemistry & geophysics
01 natural sciences
Oxygen
Mantle (geology)
Metal
chemistry.chemical_compound
light elements
accretion
Geochemistry and Petrology
Mineral redox buffer
Earth and Planetary Sciences (miscellaneous)
core formation
Petrology
0105 earth and related environmental sciences
carbon
magma ocean
Sulfur
Silicate
Geophysics
chemistry
13. Climate action
Space and Planetary Science
Magma ocean
visual_art
visual_art.visual_art_medium
sulphur
Planetary differentiation
Geology
Subjects
Details
- ISSN :
- 0012821X
- Volume :
- 391
- Database :
- OpenAIRE
- Journal :
- Earth and Planetary Science Letters
- Accession number :
- edsair.doi.dedup.....88810070717ae73967f76f16b83fc0ce