57Fe Mössbauer spectroscopy study of phlogopite megacrysts from an evolved carbonatitic kimberlite in the northeastern Oman Mountains

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The Fe oxidation degree determined by 57Fe Mössbauer spectroscopy and microprobe was used to characterize fresh and altered phlogopite megacrysts from an evolved carbonatitic kimberlite from northeastern Oman. The Quadrupole splitting (QS) varies between 2.19 and 2.48 mm/s (Fe 2∈+∈) in the fresh phlogopite samples and between 2.40 and 2.47 mm/s in the altered phlogopite samples. The quadrupole splitting of the Fe3∈+∈ doublets varies between 0.66 and 0.85 mm/s in the fresh samples. The altered phlogopite samples show three Fe 3∈+∈ doublets; the first show a quadrupole splitting between 0.97 and 1.13, the second quadrupole splitting varies between 0.24 and 0.46 mm/s and the third varies between -∈0.23 and -∈0.35 mm/s. The phlogopite was observed to have an average Fe3∈+∈/Fe total of 35% to 37%, and corresponds to fresh phlogopite. The second one results from the alteration of the first type, and the Fe 3∈+∈/Fetotal ranges between 40% and 57%. Tetrahedral Fe3∈+∈ ions were confirmed in the altered phlogopite samples. Quantitative Fe site distributions can be obtained from room-temperature Mössbauer data if the different recoilless factors for octahedral Fe2∈+∈ and tetrahedral Fe 3∈+∈ are considered. The observed isomer shifts are consistent with Mössbauer temperatures of 330 K, reported in the literature for tetrahedral and octahedral Fe3∈+∈ and Fe 2∈+∈ in phlogopite. The results are compared to those obtained for natural and synthetic phlogopite from worldwide.

Original languageEnglish
Pages (from-to)147-151
Number of pages5
JournalHyperfine Interactions
Issue number1-3
Publication statusPublished - Sep 2008



  • Fe Mössbauer spectroscopy
  • Carbonatitic kimberlite
  • Northeastern Oman Mountains

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Nuclear and High Energy Physics
  • Atomic and Molecular Physics, and Optics
  • Physical and Theoretical Chemistry

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