Formation of bridgmanite-enriched layer at the top lower-mantle during magma ocean solidification

Longjian Xie, Akira Yoneda, Daisuke Yamazaki, Geeth Manthilake, Yuji Higo, Yoshinori Tange, Nicolas Guignot, Andrew King, Mario Scheel, Denis Andrault

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

Thermochemical heterogeneities detected today in the Earth’s mantle could arise from ongoing partial melting in different mantle regions. A major open question, however, is the level of chemical stratification inherited from an early magma-ocean (MO) solidification. Here we show that the MO crystallized homogeneously in the deep mantle, but with chemical fractionation at depths around 1000 km and in the upper mantle. Our arguments are based on accurate measurements of the viscosity of melts with forsterite, enstatite and diopside compositions up to ~30 GPa and more than 3000 K at synchrotron X-ray facilities. Fractional solidification would induce the formation of a bridgmanite-enriched layer at ~1000 km depth. This layer may have resisted to mantle mixing by convection and cause the reported viscosity peak and anomalous dynamic impedance. On the other hand, fractional solidification in the upper mantle would have favored the formation of the first crust.

Original languageEnglish
Article number548
JournalNature communications
Volume11
Issue number1
DOIs
Publication statusPublished - Dec 1 2020

ASJC Scopus subject areas

  • Chemistry(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Physics and Astronomy(all)

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    Xie, L., Yoneda, A., Yamazaki, D., Manthilake, G., Higo, Y., Tange, Y., Guignot, N., King, A., Scheel, M., & Andrault, D. (2020). Formation of bridgmanite-enriched layer at the top lower-mantle during magma ocean solidification. Nature communications, 11(1), [548]. https://doi.org/10.1038/s41467-019-14071-8