How much potassium is in the Earth's core? New insights from partitioning experiments

Alexandre Corgne, Shantanu Keshav, Yingwei Fei, William F. McDonough

Research output: Contribution to journalArticlepeer-review

61 Citations (Scopus)

Abstract

The presence of potassium in the core is a vexing issue in Earth Science that is of fundamental concern to the energy budget of the Earth. New experimental data reported here for partitioning of potassium (K) between peridotitic silicate melt and Fe-Ni-S-C-O molten alloy at 1650-2200 °C and 1.0-7.7 GPa reveal a negligible effect of pressure on K partitioning, at least up to 7.7 GPa. No evidence for a systematic increase of K solubility in the alloy with temperature or pressure and S or C contents in the alloy was found. However, there is a possible increase in the K partition coefficient with increasing O content in the molten alloy. Our results, which are appropriate to model core formation in a shallow magma ocean, suggest it is unlikely to sequester more than a few tens of ppm of K into Earth's core during a magma ocean event if oxygen is not a major contributor to the light element budget of the core.

Original languageEnglish
Pages (from-to)567-576
Number of pages10
JournalEarth and Planetary Science Letters
Volume256
Issue number3-4
DOIs
Publication statusPublished - 2007 Apr 30
Externally publishedYes

Keywords

  • Earth's core
  • geodynamo
  • high pressure
  • metal-silicate partitioning
  • potassium

ASJC Scopus subject areas

  • Geophysics
  • Geochemistry and Petrology
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science

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