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Hydrogen incorporation and the oxidation state of iron in ringwoodite: A spectroscopic study

  • Maria Mrosko EMAIL logo , Stephan Lenz , Catherine A. McCamm , Michail Taran , Richard Wirth and Monika Koch-Müller
Published/Copyright: March 7, 2015
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American Mineralogist
From the journal American Mineralogist Volume 98 Issue 4

Abstract

Ringwoodite [(Mg,Fe)2SiO4] is the high-pressure polymorph of olivine stable in the upper mantle between ~525 to 660 km. Information on its temperature-dependent water content and Fe-oxidation state bears important implications on the hydrogen cycle and oxidation state of the Earth’s interior. We conducted several multi-anvil experiments to synthesize iron-bearing (0.11 ≤ xFe ≤ 0.24) hydrous ringwoodite under oxidizing and reducing conditions. The experiments were performed at 1200 °C and pressures between 16.5 and 18.3 GPa. The incorporation of hydrogen and iron in ringwoodite was studied using Fourier transform infrared (FTIR), Mössbauer (MB), ultraviolet-visible (UV-VIS), and electron energy loss (EEL) spectroscopy. For MB spectroscopy, ringwoodite enriched in 57Fe was synthesized. The IR spectra of ringwoodite show a broad OH band around 3150 cm-1 and two shoulders on the high-energy side: one intense at 3680 cm-1 and one weak at around 3420 cm-1. The water content of the samples was determined using FTIR spectroscopy to have a maximum value of 1.9(3) wt% H2O. UV-VIS spectra display a broad band around 12 700 cm-1 and a shoulder at 9900 cm-1 representing the spin-allowed dd-transitions of VIFe2+. The weaker band around 18 200 cm-1 is a distinct feature of Fe2+-Fe3+ intervalence charge transfer indicating the presence of Fe3+ in the samples. EEL spectra yield Fe3+ fractions ranging from 6(3)% at reducing conditions to 12(3)% at oxidizing conditions.

We performed heating experiments up to 600 °C in combination with in situ FTIR spectroscopy to evaluate the temperature-dependent behavior of ringwoodite, especially with respect to hydrogen incorporation. We observed a color change of ringwoodite from blue to green to brown. The heat-treated samples displayed hydrogen loss, an irreversible rearrangement of part of the hydrogen atoms (FTIR), as well as oxidation of Fe2+ to Fe3+ evidenced by the appearance of the spin-forbidden dd-transition band for Fe3+ and the ligand-metal (O2--Fe3+) transition band in the optical spectra. An increased Fe3+ fraction was also revealed by EEL and MB spectroscopy (up to 16% Fe3+/ΣFe). Analyses of MB data revealed the possibility of tetrahedral Fe3+ in the annealed ringwoodite.

These results lead to a reinterpretation of the broad OH band, which is a combination of several bands, mainly [VMg(OH)2]x), a weaker high-energy band at 3680 cm-1 ([VSi(OH)4]x) and a shoulder at 3420 cm-1 ([(Mg/Fe)Si(OH)2]x).

Keywords : Ringwoodite; water; iron; oxygen fugacity; hydrogen location; spectroscopy
Received: 2012-5-23
Accepted: 2012-12-31
Published Online: 2015-3-7
Published in Print: 2013-4-1

© 2015 by Walter de Gruyter Berlin/Boston

Articles in the same Issue

  1. Highlight and Breakthrough. A fresh look at crystals in the Bishop Tuff
  2. Actinides in Geology, Energy, and the Environment. Remobilization of U and REE and the formation of secondary minerals in oxidized U deposits
  3. Actinides in Geology, Energy, and the Environment. Revision of the symmetry and the crystal structure of čejkaite, Na4(UO2)(CO3)3
  4. Characterization of ferric arsenate-sulfate compounds: Implications for arsenic control in refractory gold processing residues
  5. Crystal structure and chemistry of skarn-associated bismuthian vesuvianite
  6. Transformation of graphite to lonsdaleite and diamond in the Goalpara ureilite directly observed by TEM
  7. Quartz nanocrystals in the 2.48 Ga Dales Gorge banded iron formation of Hamersley, Western Australia: Evidence for a change from submarine to subaerial volcanism at the end of the Archean
  8. Synthesis and characterization of amphiboles along the tremolite–glaucophane join
  9. Elasticity of franklinite and trends for transition-metal oxide spinels
  10. Redox systematics of martian magmas with implications for magnetite stability
  11. Hydrogen incorporation and the oxidation state of iron in ringwoodite: A spectroscopic study
  12. Hydrous ringwoodite to 5 K and 35 GPa: Multiple hydrogen bonding sites resolved with FTIR spectroscopy
  13. Calibration of zircon as a Raman spectroscopic pressure sensor to high temperatures and application to water-silicate melt systems
  14. Computational study of the elastic behavior of the 2M1 muscovite-paragonite series
  15. Vanadium L2,3 XANES experiments and first-principles multielectron calculations: Impact of second-nearest neighboring cations on vanadium-bearing fresnoites
  16. A time-resolved X-ray diffraction study of Cs exchange into hexagonal H-birnessite
  17. Grain-boundary diffusion rates inferred from grain-size variations of quartz in metacherts from a contact aureole
  18. On the use of unpolarized infrared spectroscopy for quantitative analysis of absorbing species in birefringent crystals
  19. A computational model of cation ordering in the magnesioferrite-qandilite (MgFe2O4- Mg2TiO4) solid solution and its potential application to titanomagnetite (Fe3O4-Fe2TiO4)
  20. 3T-phlogopite from Kasenyi kamafugite (SW Uganda): EPMA, XPS, FTIR, and SCXRD study
  21. Revision of the crystal structure and chemical formula of haiweeite, Ca(UO2)2(Si5O12)(OH)2·6H2O
  22. Cation arrangement in the octahedral and tetrahedral sheets of cis-vacant polymorph of dioctahedral 2:1 phyllosilicates by quantum mechanical calculations
  23. High-pressure phase transitions of Fe3–xTixO4 solid solution up to 60 GPa correlated with electronic spin transition
  24. Hydrogen incorporation in crystalline zircon: Insight from ab initio calculations
  25. The vibrational features of hydroxylapatite and type A carbonated apatite: A first principle contribution
  26. STEM investigation of exsolution lamellae and “c” reflections in Ca-rich dolomite from the Platteville Formation, western Wisconsin
  27. Karenwebberite, Na(Fe2+,Mn2+)PO4, a new member of the triphylite group from the Malpensata pegmatite, Lecco Province, Italy
  28. The crystal structure of ramdohrite, Pb5.9Fe0.1Mn0.1In0.1Cd0.2Ag2.8Sb10.8S24: A new refinement
  29. Static disorders of atoms and experimental determination of Debye temperature in pyrope: Low- and high-temperature single-crystal X-ray diffraction study—Discussion
  30. Static disorders of atoms and experimental determination of Debye temperature in pyrope: Low- and high-temperature single-crystal X-ray diffraction study—Reply
https://doi.org/10.2138/am.2013.4245
Keywords for this article
Ringwoodite; water; iron; oxygen fugacity; hydrogen location; spectroscopy

Articles in the same Issue

  1. Highlight and Breakthrough. A fresh look at crystals in the Bishop Tuff
  2. Actinides in Geology, Energy, and the Environment. Remobilization of U and REE and the formation of secondary minerals in oxidized U deposits
  3. Actinides in Geology, Energy, and the Environment. Revision of the symmetry and the crystal structure of čejkaite, Na4(UO2)(CO3)3
  4. Characterization of ferric arsenate-sulfate compounds: Implications for arsenic control in refractory gold processing residues
  5. Crystal structure and chemistry of skarn-associated bismuthian vesuvianite
  6. Transformation of graphite to lonsdaleite and diamond in the Goalpara ureilite directly observed by TEM
  7. Quartz nanocrystals in the 2.48 Ga Dales Gorge banded iron formation of Hamersley, Western Australia: Evidence for a change from submarine to subaerial volcanism at the end of the Archean
  8. Synthesis and characterization of amphiboles along the tremolite–glaucophane join
  9. Elasticity of franklinite and trends for transition-metal oxide spinels
  10. Redox systematics of martian magmas with implications for magnetite stability
  11. Hydrogen incorporation and the oxidation state of iron in ringwoodite: A spectroscopic study
  12. Hydrous ringwoodite to 5 K and 35 GPa: Multiple hydrogen bonding sites resolved with FTIR spectroscopy
  13. Calibration of zircon as a Raman spectroscopic pressure sensor to high temperatures and application to water-silicate melt systems
  14. Computational study of the elastic behavior of the 2M1 muscovite-paragonite series
  15. Vanadium L2,3 XANES experiments and first-principles multielectron calculations: Impact of second-nearest neighboring cations on vanadium-bearing fresnoites
  16. A time-resolved X-ray diffraction study of Cs exchange into hexagonal H-birnessite
  17. Grain-boundary diffusion rates inferred from grain-size variations of quartz in metacherts from a contact aureole
  18. On the use of unpolarized infrared spectroscopy for quantitative analysis of absorbing species in birefringent crystals
  19. A computational model of cation ordering in the magnesioferrite-qandilite (MgFe2O4- Mg2TiO4) solid solution and its potential application to titanomagnetite (Fe3O4-Fe2TiO4)
  20. 3T-phlogopite from Kasenyi kamafugite (SW Uganda): EPMA, XPS, FTIR, and SCXRD study
  21. Revision of the crystal structure and chemical formula of haiweeite, Ca(UO2)2(Si5O12)(OH)2·6H2O
  22. Cation arrangement in the octahedral and tetrahedral sheets of cis-vacant polymorph of dioctahedral 2:1 phyllosilicates by quantum mechanical calculations
  23. High-pressure phase transitions of Fe3–xTixO4 solid solution up to 60 GPa correlated with electronic spin transition
  24. Hydrogen incorporation in crystalline zircon: Insight from ab initio calculations
  25. The vibrational features of hydroxylapatite and type A carbonated apatite: A first principle contribution
  26. STEM investigation of exsolution lamellae and “c” reflections in Ca-rich dolomite from the Platteville Formation, western Wisconsin
  27. Karenwebberite, Na(Fe2+,Mn2+)PO4, a new member of the triphylite group from the Malpensata pegmatite, Lecco Province, Italy
  28. The crystal structure of ramdohrite, Pb5.9Fe0.1Mn0.1In0.1Cd0.2Ag2.8Sb10.8S24: A new refinement
  29. Static disorders of atoms and experimental determination of Debye temperature in pyrope: Low- and high-temperature single-crystal X-ray diffraction study—Discussion
  30. Static disorders of atoms and experimental determination of Debye temperature in pyrope: Low- and high-temperature single-crystal X-ray diffraction study—Reply
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