Equation of state and phase diagram of FeO
By R. Fischer, A. Campbell, G. Shofner, Oliver Thomas Lord, P. Dera, V. Prakapenka. 2011
134 citations recorded by the source corpus.
Wuestite, Fe{sub 1-x}O, is an important component in the mineralogy of Earth's lower mantle and may also be a component in the core. Therefore the high pressure, high temperature behavior of FeO, including its phase diagram and equation of state, is essential knowledge for understanding the properties and evolution of Earth's deep interior. We performed X-ray diffraction measurements using a laser-heated diamond anvil cell to achieve simultaneous high pressures and temperatures. Wuestite was mixed with iron metal, which served as our pressure standard, under the assumption that negligible oxygen dissolved into the iron. Our data show a positive slope for the subsolidus phase boundary between the B1 and B8 structures, indicating that the B1 phase is stable at the P-T conditions of the lower mantle and core. We have determined the thermal equation of state of B1 FeO to 156 GPa and 3100 K, finding an isothermal bulk modulus K{sub 0} = 149.4 {+-} 1.0 GPa and its pressure derivative K'{sub 0} = 3.60 {+-} 0.4. This implies that 7.7 {+-} 1.1 wt.% oxygen is required in the outer core to match the seismologically-determined density, under the simplifying assumption of a purely Fe-O outer core.
Subfields: Geophysics
View Paper: https://www.semanticscholar.org/paper/fabf543d40f9adb088a365b9461b46cba8fc77f7
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In Geophysics
Citations in the corpus
- Accretion and differentiation of the terrestrial planets with implications for the compositions of early-formed Solar System bodies and accretion of water (2014, methodology): “Our estimated concentrations of O and Si in the Earth’s core are consistent with estimates based on geochemical arguments (Allègre et al. 1995), partitioning experiments (Ricolleau et al., 2011; Tsuno et al., 2013) and equation of state determinations (Fischer et al., 2011, 24 2014a).”
- Phase relations in the Fe-FeSi system at high pressures and temperatures (2013, background): “Phase diagrams reveal 48 which phases’ equations of state and other properties should be compared to those of the core (e.g., 49 Fischer et al., 2011).”