Phase transition boundary between B1 and B8 structures of FeO up to 210GPa

Ozawa, Haruka; Hirose, Kei; Tateno, Shigehiko; Sata, Nagayoshi; Ohishi, Yasuo

doi:10.1016/j.pepi.2009.11.005

Cited by 73 publications

(87 citation statements)

References 40 publications

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“…It is unclear why there is so much difference between our results and the high-pressure velocities of Wicks et al (2010). We note, however, that the velocities of Wicks et al (2010) seem to be remarkably insensitive to pressure, in particular V p which only increase from 6.8 to 7.5 km/s over a pressure range of 136 GPa which may be due to the transition to a hexagonal structure above ∼80 GPa which would not be stable at lower mantle temperatures (Ozawa et al, 2010). It has also been observed that NIS measurements of sound velocities on solid solutions differ from those measured with ultra-sonic methods (Sinmyo et al, 2014).…”

Section: Elasticitycontrasting

confidence: 66%

Elastic properties of ferropericlase at lower mantle conditions and its relevance to ULVZs

Muir

Brodholt

2015

Earth and Planetary Science Letters

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Editor: P. Shearer Keywords: elasticity and anelasticity composition of the mantle equations of stateThe elasticity of Fe x Mg 1−x O was examined under lowermost mantle temperature and pressure conditions using density functional theory (DFT). The addition of iron decreases the shear modulus of MgO but has varying effects on the bulk modulus depending on the spin state of the iron. The spin state of iron in Fe x Mg 1−x O is dependent on pressure and temperature but also on the concentration of iron. At 136 GPa, Fe in low concentrations (<25%) is nearly entirely low spin, while at very high concentrations (>75%) it is nearly entirely in the high spin state. There is, as expected, a large decrease in seismic velocities with iron substitution. However, the effect of Fe is greater at high-temperatures than at low-temperatures, meaning it is difficult to extrapolate low-temperature experimental results. We cannot simultaneously match the density and seismic velocities of ULVZs with Fe-enriched ferropericlase. This is reflected in (dln V s /dln V p ) T,P , which in ULVZs is generally observed to be about 3, but does not exceed about 1.5 for Fe-enriched periclase. A mixture of ferropericlase and ferrous perovskite can cause V s decreases of up to 45%, which allows the range of ULVZ V p , V s and densities to be matched. We also find that (dln V s /dln V p ) T,P increases up to as much as 3 but this value is strongly dependent on the bounds of the mixing geometry. We conclude, therefore, that the properties of ULVZs can be readily explained by a lower mantle with a single phase that is heavily enriched in Fe.

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Section: Elasticitycontrasting

confidence: 66%

Elastic properties of ferropericlase at lower mantle conditions and its relevance to ULVZs

Muir

Brodholt

2015

Earth and Planetary Science Letters

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“…THE CANADIAN MINERALOGIST 2004), more recent experiments demonstrated that the cubic rock salt structure (B1) of wüstite is stable until 208 GPa and 3,800 K, i.e., along the whole mantle geotherm(Ozawa et al 2010). Our observation would support the idea of dissociation of Fe-rich periclase under very high pressure conditions.…”

supporting

confidence: 75%

A Microinclusion of Lower-Mantle Rock and Other Mineral and Nitrogen Lower-Mantle Inclusions in a Diamond

Kaminsky¹,

Wirth²,

Schreiber³

2015

Can Mineral

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A microcrystalline polymineral aggregate was identified as an inclusion in a diamond from the Rio Soriso area, Mato Grosso State, Brazil. It is composed of iron carbides, Fe-rich periclase (with exsolved magnesioferrite), and two orthorhombic, postspinel phases-Mg-Cr-Fe and Ca-Cr oxides, which are new mineral phases. This association was formed during several stages and may be considered as a rock microfragment from the lower mantle. In addition to the carbide-oxide fragment, other phases were identified as inclusions in the diamond, such as parascandolaite KMgF 3 (that is stable at pressures of up to 50 GPa) in association with orthorhombic MgO, and porous dolomite occurring together with nanoinclusions of calcite, apatite, spinel, Fe-sulfide, and an assemblage of periclase plus wüstite. These minerals belong to the carbonatitic association and, along with syngenetic nanoinclusions of fluid nitrogen, represent the media of diamond formation. The assemblage of periclase and wüstite within the carbonatitic matrix points to the origin of diamond from a carbonatitic environment within the lower mantle under pressure conditions of ≥85-86 GPa (~1,900 km depth).

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“…With the exception of the Fe-rich portion (22)(23)(24), relevant to planetary cores, only the polymorphism of known oxides is well investigated. Wüstite is stable to very high pressure and temperature (25), whereas magnetite undergoes a phase transition at about 10 GPa (26) into a nonrecoverable high-pressure phase having strong similarities with the phase presented in this work. Our experiment suggests that Fe 4 O 5 is stable from about 5 GPa to at least 30 GPa.…”

Section: Energetics and Stability Ofsupporting

confidence: 58%

Discovery of the recoverable high-pressure iron oxide Fe₄O₅

Lavina

Dera

Kim

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

130

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Phases of the iron–oxygen binary system are significant to most scientific disciplines, directly affecting planetary evolution, life, and technology. Iron oxides have unique electronic properties and strongly interact with the environment, particularly through redox reactions. The iron–oxygen phase diagram therefore has been among the most thoroughly investigated, yet it still holds striking findings. Here, we report the discovery of an iron oxide with formula Fe 4 O 5 , synthesized at high pressure and temperature. The previously undescribed phase, stable from 5 to at least 30 GPa, is recoverable to ambient conditions. First-principles calculations confirm that the iron oxide here described is energetically more stable than FeO + Fe 3 O 4 at pressure greater than 10 GPa. The calculated lattice constants, equation of states, and atomic coordinates are in excellent agreement with experimental data, confirming the synthesis of Fe 4 O 5 . Given the conditions of stability and its composition, Fe 4 O 5 is a plausible accessory mineral of the Earth’s upper mantle. The phase has strong ferrimagnetic character comparable to magnetite. The ability to synthesize the material at accessible conditions and recover it at ambient conditions, along with its physical properties, suggests a potential interest in Fe 4 O 5 for technological applications.

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Phase transition boundary between B1 and B8 structures of FeO up to 210GPa

Cited by 73 publications

References 40 publications

Elastic properties of ferropericlase at lower mantle conditions and its relevance to ULVZs

Elastic properties of ferropericlase at lower mantle conditions and its relevance to ULVZs

A Microinclusion of Lower-Mantle Rock and Other Mineral and Nitrogen Lower-Mantle Inclusions in a Diamond

Discovery of the recoverable high-pressure iron oxide Fe₄O₅

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Phase transition boundary between B1 and B8 structures of FeO up to 210GPa

Cited by 73 publications

References 40 publications

Elastic properties of ferropericlase at lower mantle conditions and its relevance to ULVZs

Elastic properties of ferropericlase at lower mantle conditions and its relevance to ULVZs

A Microinclusion of Lower-Mantle Rock and Other Mineral and Nitrogen Lower-Mantle Inclusions in a Diamond

Discovery of the recoverable high-pressure iron oxide Fe4O5

Contact Info

Product

Resources

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Discovery of the recoverable high-pressure iron oxide Fe₄O₅