Séminaire ISTerre

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The behavior of carbon and hydrogen in the Earth's early global magma ocean

mardi 2 février 2021 - 11h00

Natalia Solomatova - ENS Lyon
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Estimating the fluxes of volatiles during the existence of a global magma ocean is fundamental for understanding the cooling history of the early Earth and for quantifying the volatile budget of the present day. Using first-principles molecular dynamics, we predict the vaporization rate of carbon and hydrogen at the interface between the magma ocean and the hot dense atmosphere, just after the Moon-forming impact. We find that carbon is rapidly devolatilized even under pressure, while hydrogen remains dissolved in the magma. In the early stages of the magma ocean, significantly more carbon than hydrogen would have been released into the atmosphere, and it is only after the atmospheric pressure decreased, that much of the hydrogen devolatilized from the melt. Although the concentration of carbon and the oxidation state of the melts do not affect the overall volatility of carbon, they dictate the speciation of the vaporized carbon molecules (i.e., the ratio of carbon dioxide to carbon monoxide). With increasing pressure, carbon becomes increasingly polymerized intocomplex carbon-iron clusters, suggesting that iron may partition a significant fraction of carbon from the silicate melt, leading to the transportation of carbon to the lowermost mantle and potentially into the liquid outer iron core.

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Equipe organisatrice : Géodynamo

Séminaire uniquement en visio

Informations de visio :

https://univ-grenoble-alpes-fr.zoom.us/j/98956376487?pwd=TTdhWGJ1d3Z6OG4rS1UzWmNGYVVxZz09