Abstract
Aluminous bridgmanite (Al-Bm) is the dominant phase in the Earth’s lower mantle. In this study, the Mössbauer spectra of an Al-Bm sample Mg0.868Fe0.087Si0.944Al0.101O2.994 were recorded from 65 to 300 K at 1 bar. The temperature dependence of the center shift was fitted by the Debye model and yielded the Debye temperatures of 305 ± 3 K for Fe2+ and 361 ± 22 K for Fe3+. These values are lower than those of Al-free bridgmanite by 17 and 24%, respectively, indicating that the presence of Fe and Al increases the average Fe-O bond length and weakens the bond strength. At 300 K, the calculated recoil-free fractions of Fe2+ (0.637 ± 0.006) and Fe3+ (0.72 ± 0.02) are similar and therefore the molar fractions of Fe2+ and Fe3+ are nearly the same as the area fractions of the corresponding Mössbauer doublets. At 900 K, the calculated recoil-free fractions of Fe3+ is 46% higher than that of Fe2+, implying that the molar fraction of Fe3+ is only 41% for a measured spectral area fraction of 50%, and that the area fractions of iron sites may change with temperature without any changes in the valence state or spin state of iron. We infer that Fe3+ accounts for 46 ± 2% of the iron in the Al-Bm and it enters the A site along with Al3+ in the B site through the coupled-substitution mechanism. An Fe2+ component with large quadrupole splitting (~4.0 mm/s) was observed at cryogenic conditions and interpreted as a high-spin distorted iron site.
© 2015 by Walter de Gruyter Berlin/Boston
Artikel in diesem Heft
- Data, ideas, and the nature of scientific progress
- Beyond the equilibrium paradigm: How consideration of kinetics enhances metamorphic interpretation
- Magmatic volatiles (H, C, N, F, S, Cl) in the lunar mantle, crust, and regolith: Abundances, distributions, processes, and reservoirs
- The mafic component of the lunar crust: Constraints on the crustal abundance of mantle and intrusive rock, and the mineralogy of lunar anorthosites
- Degassing pathways of Cl-, F-, H-, and S-bearing magmas near the lunar surface: Implications for the composition and Cl isotopic values of lunar apatite
- Uranium scavenging during mineral replacement reactions
- New structure of high-pressure body-centered orthorhombic Fe2SiO4
- Spectroscopic study of ordering in non-stoichiometric magnesium aluminate spinel
- High-pressure behavior of cuprospinel CuFe2O4: Influence of the Jahn-Teller effect on the spinel structure
- Field and model constraints on silicic melt segregation by compaction/hindered settling: The role of water and its effect on latent heat release
- Formation of rhyolite at the Okataina Volcanic Complex, New Zealand: New insights from analysis of quartz clusters in plutonic lithics
- Experimental investigation of F, Cl, and OH partitioning between apatite and Fe-rich basaltic melt at 1.0–1.2 GPa and 950–1000 °C
- Synthesis, characterization, and thermodynamics of arsenates forming in the Ca-Fe(III)-As(V)-NO3 system: Implications for the stability of Ca-Fe arsenates
- High-pressure phases of cordierite from single-crystal X-ray diffraction to 15 GPa
- Planar microstructures in zircon from paleo-seismic zones
- Ultra-deep subduction of Yematan eclogite in the North Qaidam UHP belt, NW China: Evidence from phengite exsolution in omphacite
- Elastic wave velocity anomalies of anorthite in a subducting plate: In situ experiments
- Current limitations of molecular dynamic simulations as probes of thermo-physical behavior of silicate melts
- Three-component mixed-layer illite/smectite/kaolinite (I/S/K) minerals in hydromorphic soils, south China
- Melting curve of NaCl to 20 GPa from electrical measurements of capacitive current
- Grain size measurement from two-dimensional micro-X-ray diffraction: Laboratory application of a radial integration technique
- Decrease of hydrogen incorporation in forsterite from CO2-H2O-rich kimberlitic liquid
- Provenance determination of sapphires and rubies using laser-induced breakdown spectroscopy and multivariate analysis
- Structural insights and elasticity of single-crystal antigorite from high-pressure Raman and Brillouin spectroscopy measured in the (010) plane
- Magnetic anisotropy in natural amphibole crystals
- Resolving oxygen isotopic disturbance in zircon: A case study from the low δ18O Scourie dikes, NW Scotland
- Accurate determination of Fe3+/ΣFe of andesitic glass by Mössbauer spectroscopy
- Recoil-free fractions of iron in aluminous bridgmanite from temperature-dependent Mössbauer spectra
- Chemical interactions between a sedimentary diapir and surrounding magma: Evidence from the Phepane Dome and Bushveld Complex, South Africa
- The crystal structures of Mg2Fe2C4O13, with tetrahedrally coordinated carbon, and Fe13O19, synthesized at deep mantle conditions
- New Mineral Names
- Book Review: Geodynamics, Third edition.
Artikel in diesem Heft
- Data, ideas, and the nature of scientific progress
- Beyond the equilibrium paradigm: How consideration of kinetics enhances metamorphic interpretation
- Magmatic volatiles (H, C, N, F, S, Cl) in the lunar mantle, crust, and regolith: Abundances, distributions, processes, and reservoirs
- The mafic component of the lunar crust: Constraints on the crustal abundance of mantle and intrusive rock, and the mineralogy of lunar anorthosites
- Degassing pathways of Cl-, F-, H-, and S-bearing magmas near the lunar surface: Implications for the composition and Cl isotopic values of lunar apatite
- Uranium scavenging during mineral replacement reactions
- New structure of high-pressure body-centered orthorhombic Fe2SiO4
- Spectroscopic study of ordering in non-stoichiometric magnesium aluminate spinel
- High-pressure behavior of cuprospinel CuFe2O4: Influence of the Jahn-Teller effect on the spinel structure
- Field and model constraints on silicic melt segregation by compaction/hindered settling: The role of water and its effect on latent heat release
- Formation of rhyolite at the Okataina Volcanic Complex, New Zealand: New insights from analysis of quartz clusters in plutonic lithics
- Experimental investigation of F, Cl, and OH partitioning between apatite and Fe-rich basaltic melt at 1.0–1.2 GPa and 950–1000 °C
- Synthesis, characterization, and thermodynamics of arsenates forming in the Ca-Fe(III)-As(V)-NO3 system: Implications for the stability of Ca-Fe arsenates
- High-pressure phases of cordierite from single-crystal X-ray diffraction to 15 GPa
- Planar microstructures in zircon from paleo-seismic zones
- Ultra-deep subduction of Yematan eclogite in the North Qaidam UHP belt, NW China: Evidence from phengite exsolution in omphacite
- Elastic wave velocity anomalies of anorthite in a subducting plate: In situ experiments
- Current limitations of molecular dynamic simulations as probes of thermo-physical behavior of silicate melts
- Three-component mixed-layer illite/smectite/kaolinite (I/S/K) minerals in hydromorphic soils, south China
- Melting curve of NaCl to 20 GPa from electrical measurements of capacitive current
- Grain size measurement from two-dimensional micro-X-ray diffraction: Laboratory application of a radial integration technique
- Decrease of hydrogen incorporation in forsterite from CO2-H2O-rich kimberlitic liquid
- Provenance determination of sapphires and rubies using laser-induced breakdown spectroscopy and multivariate analysis
- Structural insights and elasticity of single-crystal antigorite from high-pressure Raman and Brillouin spectroscopy measured in the (010) plane
- Magnetic anisotropy in natural amphibole crystals
- Resolving oxygen isotopic disturbance in zircon: A case study from the low δ18O Scourie dikes, NW Scotland
- Accurate determination of Fe3+/ΣFe of andesitic glass by Mössbauer spectroscopy
- Recoil-free fractions of iron in aluminous bridgmanite from temperature-dependent Mössbauer spectra
- Chemical interactions between a sedimentary diapir and surrounding magma: Evidence from the Phepane Dome and Bushveld Complex, South Africa
- The crystal structures of Mg2Fe2C4O13, with tetrahedrally coordinated carbon, and Fe13O19, synthesized at deep mantle conditions
- New Mineral Names
- Book Review: Geodynamics, Third edition.