Roth, A.S.G. and Liebske, C. and Maden, C. and Burton, K.W. and Schönbächler, M. and Busemann, H. (2019) 'The primordial He budget of the Earth set by percolative core formation in planetesimals.', Geochemical perspectives letters., 9 . pp. 26-31.
The primordial He budget of the Earth’s interior is commonly thought to have been set by full liquid metal-silicate equilibration in a terrestrial magma ocean. However, incomplete metal-silicate equilibration during accretion will have a substantial effect on this budget. Here we present liquid-solid partitioning experiments indicating that He behaves as a moderately siderophile element during percolative core formation in planetesimals. Mass balance considerations show that even minor disequilibrium will allow the Earth’s early core to incorporate sufficient primordial He—and possibly other noble gases—to supply the lower mantle throughout Earth’s history. We conclude that the high 3He/4He ratios in basalts may well represent primarily the last vestiges of metal-silicate disequilibrium in a terrestrial magma ocean preserved from the time of Earth’s formation.
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|Publisher Web site:||https://doi.org/10.7185/geochemlet.1901|
|Publisher statement:||This work is distributed under the Creative Commons Attribution Non-Commercial No-Derivatives 4.0 License, which permits unrestricted distribution provided the original author and source are credited. The material may not be adapted (remixed, transformed or built upon) or used for commercial purposes without written permission from the author. Additional information is available at http://www.geochemicalperspectivesletters.org/ copyright-and-permissions.|
|Date accepted:||19 November 2018|
|Date deposited:||29 May 2019|
|Date of first online publication:||21 January 2019|
|Date first made open access:||No date available|
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