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

• Xie, Longjian

• Yoneda, Akira

• Yamazaki, Daisuke

• Manthilake, Geeth

• Higo, Yuji

• Tange, Yoshinori

• Guignot, Nicolas

• King, Andrew

• Scheel, Mario

• Andrault, Denis

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 similar 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 similar to 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.

Journal

• Nature Communications

  Nature Communications 11 (1), 4387-, 2020-01-28

  Nature Research

Keywords

• General Physics and Astronomy
• General Biochemistry, Genetics and Molecular Biology
• General Chemistry
• Multidisciplinary

Details

• CRID: 1050567175299054336
• NII Article ID: 120006884919
• NII Book ID: AA12645905
• ISSN: 20411723
• DOI: 10.1038/s41467-019-14071-8
• Web Site: https://ousar.lib.okayama-u.ac.jp/60715
• Web Site: https://www.nature.com/articles/s41467-019-14071-8.pdf
• Web Site: https://www.nature.com/articles/s41467-019-14071-8
• Text Lang: en
• Article Type: journal article
• Data Source:
  • IRDB
  • Crossref
  • CiNii Articles
  • KAKEN