Core-mantle partitioning and the bulk Earth abundances of hydrogen and carbon: Implications for their origins

Fuente: arXiv
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Main Authors: Tsutsumi, Yutaro, Sakamoto, Naoya, Hirose, Kei, Mita, Shuhei, Yokoo, Shunpei, Hsu, Han, Yurimoto, Hisayoshi
Format: Preprint
Published: 2025
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author Tsutsumi, Yutaro
Sakamoto, Naoya
Hirose, Kei
Mita, Shuhei
Yokoo, Shunpei
Hsu, Han
Yurimoto, Hisayoshi
author_facet Tsutsumi, Yutaro
Sakamoto, Naoya
Hirose, Kei
Mita, Shuhei
Yokoo, Shunpei
Hsu, Han
Yurimoto, Hisayoshi
contents We determined the metal/silicate partition coefficients of hydrogen and carbon, DH and DC, simultaneously under typical conditions of Earth's core formation. Experiments demonstrate that both DH and DC diminish in the presence of carbon and hydrogen, respectively, indicating their strong interactions in liquid metal. With these partitioning data, we investigated the core and bulk Earth abundances of hydrogen and carbon based on core formation scenarios that are compatible with the bulk silicate Earth composition and the mass fraction and density deficit of the core. The results of the single-stage core formation modelling are markedly different from those using DH and DC individually determined in earlier experiments, indicating that the Earth building blocks do not match enstatite chondrites in water abundance and require contributions by carbonaceous chondrites. The multi-stage core formation models combined with an Earth accretion scenario accounting for isotopic composition show 0.18-0.49 wt% H and 0.19-1.37 wt% C in the core, leading to 0.53-1.40 wt% H2O (present as H in the core) and 0.07-0.44 wt% C in the bulk Earth. Our modelling also demonstrates that up to 53% and 72% of Earth's water (hydrogen) and carbon, respectively, could have been derived from non-carbonaceous chondritic materials.
format Preprint
id arxiv_https___arxiv_org_abs_2508_17740
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Core-mantle partitioning and the bulk Earth abundances of hydrogen and carbon: Implications for their origins
Tsutsumi, Yutaro
Sakamoto, Naoya
Hirose, Kei
Mita, Shuhei
Yokoo, Shunpei
Hsu, Han
Yurimoto, Hisayoshi
Earth and Planetary Astrophysics
Materials Science
We determined the metal/silicate partition coefficients of hydrogen and carbon, DH and DC, simultaneously under typical conditions of Earth's core formation. Experiments demonstrate that both DH and DC diminish in the presence of carbon and hydrogen, respectively, indicating their strong interactions in liquid metal. With these partitioning data, we investigated the core and bulk Earth abundances of hydrogen and carbon based on core formation scenarios that are compatible with the bulk silicate Earth composition and the mass fraction and density deficit of the core. The results of the single-stage core formation modelling are markedly different from those using DH and DC individually determined in earlier experiments, indicating that the Earth building blocks do not match enstatite chondrites in water abundance and require contributions by carbonaceous chondrites. The multi-stage core formation models combined with an Earth accretion scenario accounting for isotopic composition show 0.18-0.49 wt% H and 0.19-1.37 wt% C in the core, leading to 0.53-1.40 wt% H2O (present as H in the core) and 0.07-0.44 wt% C in the bulk Earth. Our modelling also demonstrates that up to 53% and 72% of Earth's water (hydrogen) and carbon, respectively, could have been derived from non-carbonaceous chondritic materials.
title Core-mantle partitioning and the bulk Earth abundances of hydrogen and carbon: Implications for their origins
topic Earth and Planetary Astrophysics
Materials Science
url https://arxiv.org/abs/2508.17740