Subduction-related oxidation of the sublithospheric mantle evidenced by ferropericlase and magnesiowüstite diamond inclusions

  • Ekaterina S. Kiseeva
  • , Nester Korolev
  • , Iuliia Koemets
  • , Dmitry A. Zedgenizov
  • , Richard Unitt
  • , Catherine McCammon
  • , Alena Aslandukova
  • , Saiana Khandarkhaeva
  • , Timofey Fedotenko
  • , Konstantin Glazyrin
  • , Dimitrios Bessas
  • , Georgios Aprilis
  • , Alexandr I. Chumakov
  • , Hiroyuki Kagi
  • , Leonid Dubrovinsky

Research output: Contribution to journalArticlepeer-review

Abstract

Ferropericlase (Mg,Fe)O is the second most abundant mineral in Earth’s lower mantle and a common inclusion found in subcratonic diamonds. Pyrolitic mantle has Mg# (100 × Mg/(Mg+Fe)) ~89. However, ferropericlase inclusions in diamonds show a broad range of Mg# between 12 and 93. Here we use Synchrotron Mössbauer Source (SMS) spectroscopy and single-crystal X-ray diffraction to determine the iron oxidation state and structure of two magnesiowüstite and three ferropericlase inclusions in diamonds from São Luiz, Brazil. Inclusion Mg#s vary between 16.1 and 84.5. Ferropericlase inclusions contain no ferric iron within the detection limit of SMS, while both magnesiowüstite inclusions show the presence of monocrystalline magnesioferrite ((Mg,Fe)Fe3+2O4) with an estimated 47–53 wt% Fe2O3. We argue that the wide range of Fe concentrations observed in (Mg,Fe)O inclusions in diamonds and the appearance of magnesioferrite result from oxidation of ferropericlase triggered by the introduction of subducted material into sublithospheric mantle.

Original languageEnglish
Article number7517
JournalNature Communications
Volume13
Issue number1
DOIs
Publication statusPublished - Dec 2022

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