Theoretical and experimental evidence for a post-perovskite phase of MgSiO3 in Earth's D″ layer

By Artem R. Oganov, Shigeaki Ono. Nature, 2004

937 citations recorded by the source corpus.

The Earth's lower mantle is believed to be composed mainly of (Mg,Fe)SiO3 perovskite, with lesser amounts of (Mg,Fe)O and CaSiO3 (ref. 1). But it has not been possible to explain many unusual properties of the lowermost ∼150 km of the mantle (the D″ layer) with this mineralogy. Here, using ab initio simulations and high-pressure experiments, we show that at pressures and temperatures of the D″ layer, MgSiO3 transforms from perovskite into a layered CaIrO3-type post-perovskite phase. The elastic properties of the post-perovskite phase and its stability field explain several observed puzzling properties of the D″ layer: its seismic anisotropy, the strongly undulating shear-wave discontinuity at its top and possibly the anticorrelation between shear and bulk sound velocities.

Subfields: Electronic, Optical and Magnetic Materials, Geophysics

View Paper: https://www.semanticscholar.org/paper/0c5bfde7fa921cfde03826cdf6ea78c4f12abd3e

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Citations in the corpus

Reconciling dynamic and seismic models of Earth's lower mantle: The dominant role of thermal heterogeneity (2012, background): “This approach naturally accounts for the sensitivity of seismic velocities to pressure, temperature, composition and phase, inclusive of the post-perovskite phase at lowermost mantle depths (e.g. Sidorin et al., 1999; Oganov and Ono, 2004; Murakami et al., 2004).”
Valence state and spin transitions of iron in Earth's mantle silicates (2006, background): “), in particular of MgSiO3 perovskite (Pv) and post-perovskite (PPv) [6,7].”
The geodynamic equation of state: What and how (2009, background): “In regard to the latter, the recent discovery of a postperovskite lower mantle phase is of particular interest [Oganov and Ono, 2004]; e.g., if the postperovskite transition has a Clapeyron slope of 10 MPa/K, then the mechanical work done during this transformation at 2500 K and 125 GPa is five…”
Spin state of ferric iron in MgSiO3 perovskite and its effect on elastic properties (2010, methodology): “For SMS above 100 GPa, we did not anneal in order to avoid a phase transition from Pv to post-Pv (PPv) at high temperature (Murakami et al., 2004; Oganov and Ono, 2004; Shim et al., 2004).”
Stagnant slab : A review (2009, background): “…mineral chemistry and density of MORB composition to show that the post-perovskite transition (Murakami et al., 2004; Tsuchiya et al., 2004; Oganov and Ono, 2004) of MORB composition starts at a pressure lower than the transition pressure for pure MgSiO3 perovskite and ends at that…”
USPEX - Evolutionary crystal structure prediction (2006, background): “was found [17,18] only after an analogous phase was identified for Fe2O3 [19].”
The MgSiO3 system at high pressure: Thermodynamic properties of perovskite, postperovskite, and melt from global inversion of shock and static compression data (2009, background): “Anomalies associated with D00 have been popularly explained by the recently discovered perovskite to postperovskite phase transition in (Mg,Fe)SiO3 [Murakami et al., 2004; Oganov and Ono, 2004; Hirose, 2006], which was predicted by the seismological study of Sidorin et al. [1999].”
Density-Functional Perturbation Theory for Quasi-Harmonic Calculations (2011, neutral): “…boundary in these minerals (perovskite→post-perovskiteMgSiO3 and spinel→postspinel Mg2SiO4) have been extensively studied(Wentzcovitch et al. 2006, Oganov & Ono 2004, Oganov & Price 2005, Wu & Wentzcovitch 2009, Yu et al. 2007, Wu et al. 2008, Yu et al. 2008, Ono & Oganov 2005) due to their…”
Postperovskite phase transition and its geophysical implications (2006, background): “The elastic properties were calculated both at 0 K [Tsuchiya et al., 2004b; Iitaka et al., 2004; Oganov and Ono, 2004] and high temperatures [Stackhouse et al., 2005; Wookey et al., 2005; Wentzcovitch et al., 2006].”
Anisotropic shear‐wave velocity structure of the Earth's mantle: A global model (2008, neutral): “The presence of the anisotropic post-Perovskite phase in the lowermost mantle has been suggested by experimental results [Murakami et al., 2004; Oganov and Ono, 2004; Shim et al., 2004].”
TX2019slab: A New P and S Tomography Model Incorporating Subducting Slabs (2019, background): “Bridgmanite could transform to pPv in the deepest ~400‐km mantle (Murakami et al., 2004; Oganov & Ono, 2004; Tsuchiya et al., 2004).”