Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
On the P-T fO(2) stability of Fe4O5, Fe5O6 and Fe4O5-rich solid solutions
Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK). Universit├Ąt Bayreuth, Germany.
Show others and affiliations
Number of Authors: 6
2016 (English)In: Contributions to Mineralogy and Petrology, ISSN 0010-7999, E-ISSN 1432-0967, Vol. 171, no 5, 151Article in journal (Refereed) Published
Abstract [en]

The high-pressure phases Fe4O5 and Fe506 have recently been added to the list of known iron oxides. As mixed -valence phases, it has been suggested that they could form in the Earth's mantle once the dominant minerals become saturated in ferric iron. The possibility that Fe4O5 could exist in the mantle is also supported by the fact that it forms extensive solid solutions with both Mg2+ and Cr3+. In this study, we present the results of high-pressure and high-temperature multi -anvil experiments performed between 5 and 24 GPa at 1000-1400 degrees C aimed at constraining the stability field of the Fe4O5 phase. We combine these results with published phase equilibria, equation of state and Fe Mg partitioning data to estimate the thermodynamic properties of Fe4O5, Fe5O6 and the (Mg,Fe)(2)Fe2O5 solid solution. Using our thermodynamic model, the oxygen fugacity at which the high-pressure iron oxides become stable is calculated and the redox stability of (Mg,Fe)(2)Fe2O5 in an assemblage of olivine and pyroxene is calculated as a function of the bulk Fe/(Fe + Mg) ratio. Fe4O5 and (Mg,Fe)(2)Fe2O5 are stable at oxygen fugacities higher than the diamond stability field and are, therefore, unlikely to be found as inclusions in diamonds. The stability field of Fe5O6, on the other hand, extends to oxygen fugacities compatible with diamond formation. Using the Mg Fe solid solution model, we show that Fe4O5-structured phases would be restricted to aluminium -poor environments in the mantle such as dunites or silica iron oxide rich sediments transported into the mantle via subduction.

Place, publisher, year, edition, pages
2016. Vol. 171, no 5, 151
Keyword [en]
Fe4O5, Fe5O6, Thermodynamics, Oxygen fugacity, Mantle, Deep Earth
National Category
Chemical Sciences
Research subject
Inorganic Chemistry
Identifiers
URN: urn:nbn:se:su:diva-132005DOI: 10.1007/s00410-016-1258-4ISI: 000377047900014OAI: oai:DiVA.org:su-132005DiVA: diva2:948176
Available from: 2016-07-08 Created: 2016-07-05 Last updated: 2017-08-29Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full text

Search in DiVA

By author/editor
Ojwang, Dickson O.
By organisation
Department of Materials and Environmental Chemistry (MMK)
In the same journal
Contributions to Mineralogy and Petrology
Chemical Sciences

Search outside of DiVA

GoogleGoogle Scholar

Altmetric score

Total: 3 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf