Low Melting Temperature of Anhydrous Mantle Materials at the Core-Mantle Boundary

Taehyun Kim, Byeongkwan Ko, Eran Greenberg, Vitali Prakapenka, Sang Heon Shim, Yongjae Lee

Research output: Contribution to journalArticlepeer-review

Abstract

One of the central challenges in accurately estimating the mantle melting temperature is the sensitivity of the probe for detecting a small amount of melt at the solidus. To address this, we used a multichannel collimator to enhance the diffuse X-ray scattering from a small amount of melt and probed an eutectic pyrolitic composition to increase the amount of melt at the solidus. Our in situ detection of diffuse scattering from the pyrolitic melt determined an anhydrous melting temperature of 3,302 ± 100 K at 119 ± 6 GPa and 3,430 ± 130 K at the core-mantle boundary (CMB) conditions, as the upper bound temperature. Our CMB temperature is approximately 700 K lower than the previous estimates, implying much faster secular cooling and higher concentrations of S, C, O, and/or H in the region, and nonlinear, advocating the basal magma ocean hypothesis.

Original languageEnglish (US)
Article numbere2020GL089345
JournalGeophysical Research Letters
Volume47
Issue number20
DOIs
StatePublished - Oct 28 2020

Keywords

  • core-mantle boundary
  • diffuse scattering
  • pyrolite
  • solidus temperature

ASJC Scopus subject areas

  • Geophysics
  • Earth and Planetary Sciences(all)

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