Low hydrogen contents in the cores of terrestrial planets
Open Access
- 1 March 2018
- journal article
- research article
- Published by American Association for the Advancement of Science (AAAS) in Science Advances
- Vol. 4 (3), e1701876
- https://doi.org/10.1126/sciadv.1701876
Abstract
Hydrogen has been thought to be an important light element in Earth's core due to possible siderophile behavior during core-mantle segregation. We reproduced planetary differentiation conditions using hydrogen contents of 450 to 1500 parts per million (ppm) in the silicate phase, pressures of 5 to 20 GPa, oxygen fugacity varying within IW-3.7 and IW-0.2 (0.2 to 3.7 log units lower than iron-wustite buffer), and Fe alloys typical of planetary cores. We report hydrogen metal-silicate partition coefficients of similar to 2 x 10(-1), up to two orders of magnitude lower than reported previously, and indicative of lithophile behavior. Our results imply H contents of similar to 60 ppm in the Earth and Martian cores. A simple water budget suggests that 90% of the water initially present in planetary building blocks was lost during planetary accretion. The retained water segregated preferentially into planetary mantles.Funding Information
- European Regional Development Fund
- French Government Laboratory of Excellence (ANR-10-LABX-0006)
- CNRS_INSU, Program: PNP
- ANR, Project: Oxy-Deep
- ANR, Project: Hy-Deep
- Laboratory of Excellence ClerVolc
- CNRS
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