The effect of oxygen fugacity on the olivine to wadsleyite transformation: Implications for remote sensing of mantle redox state at the 410 km seismic discontinuity
-
Daniel J. Frost
and
Catherine A. McCammon
Abstract
High-pressure and -temperature multianvil experiments were performed to test the effect of varying oxygen fugacity on the olivine to wadsleyite transformation. Two capsules, containing samples of (FeMg)2SiO4, were placed in each experiment; the first buffered the oxygen fugacity with an assemblage of Re and ReO2. whereas the second ensured the lowest possible ferric iron concentra- tion through the presence of excess Fe metal. Measurements of coexisting olivine, wadsleyite. and ringwoodite compositions from the Fe metal saturated experiments were used to accurately determine the pressure in each experiment using established phase relations. Under the more oxidizing conditions of the Re-ReO2 buffer, the stability field of wadsleyite was found to expand with respect to both the olivine and ringwoodite stability fields. Mössbauer spectroscopy measurements reveal Fe3+/∑Fe ratios for wadsleyite buffered by Re-ReO: of 0.1-0.25. while olivine appears to be FeJ"-free. A thermodynamic model that employs the wadsleyite end-members (Fe3+5/3□1/3)Fe3+O4-Fe2SiO4-Mg2SiO4 is used to examine the effect of varying bulk mantle Fe3+/∑Fe ratio on the depth and depth interval of the 410 km seismic discontinuity. Fe3+/SFe ratios in the range 0.02-0.12 would cause the depth interval or thickness of the 410 km discontinuity to increase from -8 to 15 km but would haw very little effect on the seismically observable absolute depth. Very large bulk mantle Fe3+/∑Fe ratios (>0.2), unrepresented in recovered mantle samples, would be required to explain recent seismic observations that the depth interval of the 410 km may be >20 km beneath certain regions. Such observations are more likely to be explained by moderate local enrichments in both ferric iron and H;0 in the mantle, most likely as a result of slab interaction.
© 2015 by Walter de Gruyter Berlin/Boston
Articles in the same Issue
- 27Al NMR spectroscopy at multiple magnetic fields and ab initio quantum modeling for kaolinite
- The effect of oxygen fugacity on the olivine to wadsleyite transformation: Implications for remote sensing of mantle redox state at the 410 km seismic discontinuity
- Spectroscopic characteristics of synthetic olivine: An integrated multi-wavelength and multi-technique approach
- Effects of hydration on thermal expansion of forsterite, wadsleyite, and ringwoodite at ambient pressure
- Forsterite, hydrous and anhydrous wadsleyite and ringwoodite (Mg2SiO4): 29Si NMR results for chemical shift anisotropy, spin-lattice relaxation, and mechanism of hydration
- Structural transitions and electron transfer in coffinite, USiO4, at high pressure
- Fe-Mg partitioning between perovskite and ferropericlase in the lower mantle
- Primitive oxygen-isotope ratio recorded in magmatic zircon from the Mid-Atlantic Ridge
- Determination of the potential for extrinsic color development in natural colorless quartz
- X-ray diffraction and Raman spectroscopic study of clinopyroxenes with six-coordinated Si in the Na(Mg0.5Si0.5)Si2O6-NaAlSi2O6 system
- Phase behavior of protoenstatite at high pressure studied by atomistic simulations
- Metasomatic replacement of inherited metamorphic monazite in a biotite-garnet granite from the Nízke Tatry Mountains, Western Carpathians, Slovakia: Chemical dating and evidence for disequilibrium melting
- Shear viscosity and diffusion in liquid MgSiO3: Transport properties and implications for terrestrial planet magma oceans
- Polarized infrared spectroscopic study of diffusion of water molecules along structure channels in beryl
- The vibrational spectrum of lizardite-1T [Mg3Si2O5(OH)4] at the Γ point: A contribution from an ab initio periodic B3LYP calculation
- Origins of Mount St. Helens cataclasites: Experimental insights
- The crystal structure and hydrogen bonding of synthetic konyaite, Na2Mg(SO4)2·5H2O
- Joëlbruggerite, Pb3Zn3(Sb5+,Te6+)As2O13(OH,O), the Sb5+ analog of dugganite, from the Black Pine mine, Montana
- Cathodoluminescence characterization of tridymite and cristobalite: Effects of electron irradiation and sample temperature
- Sequential extraction and DXRD applicability to poorly crystalline Fe- and Al-phase characterization from an acid mine water passive remediation system
- Thermoelasticity of ε-FeSi to 8 GPa and 1273 K
- Demicheleite-(Cl), BiSCl, a new mineral from La Fossa crater, Vulcano, Aeolian Islands, Italy
- Biomineralization associated with microbial reduction of Fe3+ and oxidation of Fe2+ in solid minerals
- Evidence for residual elastic strain in deformed natural quartz
- Mineralogy of mine waste at the Vermont Asbestos Group mine, Belvidere Mountain, Vermont
- Structural parameters of chromite included in diamond and kimberlites from Siberia: A new tool for discriminating ultramafic source
- Structure determination of the 2.5 hydrate MgSO4 phase by simulated annealing
Articles in the same Issue
- 27Al NMR spectroscopy at multiple magnetic fields and ab initio quantum modeling for kaolinite
- The effect of oxygen fugacity on the olivine to wadsleyite transformation: Implications for remote sensing of mantle redox state at the 410 km seismic discontinuity
- Spectroscopic characteristics of synthetic olivine: An integrated multi-wavelength and multi-technique approach
- Effects of hydration on thermal expansion of forsterite, wadsleyite, and ringwoodite at ambient pressure
- Forsterite, hydrous and anhydrous wadsleyite and ringwoodite (Mg2SiO4): 29Si NMR results for chemical shift anisotropy, spin-lattice relaxation, and mechanism of hydration
- Structural transitions and electron transfer in coffinite, USiO4, at high pressure
- Fe-Mg partitioning between perovskite and ferropericlase in the lower mantle
- Primitive oxygen-isotope ratio recorded in magmatic zircon from the Mid-Atlantic Ridge
- Determination of the potential for extrinsic color development in natural colorless quartz
- X-ray diffraction and Raman spectroscopic study of clinopyroxenes with six-coordinated Si in the Na(Mg0.5Si0.5)Si2O6-NaAlSi2O6 system
- Phase behavior of protoenstatite at high pressure studied by atomistic simulations
- Metasomatic replacement of inherited metamorphic monazite in a biotite-garnet granite from the Nízke Tatry Mountains, Western Carpathians, Slovakia: Chemical dating and evidence for disequilibrium melting
- Shear viscosity and diffusion in liquid MgSiO3: Transport properties and implications for terrestrial planet magma oceans
- Polarized infrared spectroscopic study of diffusion of water molecules along structure channels in beryl
- The vibrational spectrum of lizardite-1T [Mg3Si2O5(OH)4] at the Γ point: A contribution from an ab initio periodic B3LYP calculation
- Origins of Mount St. Helens cataclasites: Experimental insights
- The crystal structure and hydrogen bonding of synthetic konyaite, Na2Mg(SO4)2·5H2O
- Joëlbruggerite, Pb3Zn3(Sb5+,Te6+)As2O13(OH,O), the Sb5+ analog of dugganite, from the Black Pine mine, Montana
- Cathodoluminescence characterization of tridymite and cristobalite: Effects of electron irradiation and sample temperature
- Sequential extraction and DXRD applicability to poorly crystalline Fe- and Al-phase characterization from an acid mine water passive remediation system
- Thermoelasticity of ε-FeSi to 8 GPa and 1273 K
- Demicheleite-(Cl), BiSCl, a new mineral from La Fossa crater, Vulcano, Aeolian Islands, Italy
- Biomineralization associated with microbial reduction of Fe3+ and oxidation of Fe2+ in solid minerals
- Evidence for residual elastic strain in deformed natural quartz
- Mineralogy of mine waste at the Vermont Asbestos Group mine, Belvidere Mountain, Vermont
- Structural parameters of chromite included in diamond and kimberlites from Siberia: A new tool for discriminating ultramafic source
- Structure determination of the 2.5 hydrate MgSO4 phase by simulated annealing
