2.05 - Mineralogy of the Deep Mantle – The Post-Perovskite Phase and its Geophysical Significance
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Phase stability and thermal equation of state of δ-AlOOH: Implication for water transportation to the Deep Lower Mantle
2018, Earth and Planetary Science LettersDeformation, crystal preferred orientations, and seismic anisotropy in the Earth's D″ layer
2018, Earth and Planetary Science LettersCitation Excerpt :D″ is expected to be mainly composed of (Mg,Fe)SiO3 (∼70%) and (Mg,Fe)O – ferropericlase (Hirose et al., 2015). Experimental results, atomistic modeling, and seismological observations converge to (Mg,Fe)SiO3 being present as bridgmanite, with an orthorhombic perovskite (Pv) structure in hot zones of D″, but acquiring a post-perovskite (PPv) structure in colder regions (cf. review in Hirose et al., 2015). Seismic velocities in D″ show strong lateral variations at both small and large wavelengths, indicating thermal and chemical heterogeneity (e.g., Lay et al., 1998; van der Hilst et al., 2007).
Phase transition and thermal equations of state of (Fe,Al)-bridgmanite and post-perovskite: Implication for the chemical heterogeneity at the lowermost mantle
2018, Earth and Planetary Science LettersCitation Excerpt :Yet there is a large uncertainty in the transition thickness in the MORB composition, ranging from 5 GPa in Ohta et al. (2008) to 12 GPa in Grocholski et al. (2012) at 2500 K. The transition thickness in the MORB composition is much narrower than that in the single component system potentially due to the partition of Fe to the calcium–ferrite-type aluminous (CF) phase and Al to the high-pressure phase of SiO2 and/or the CF phase (Grocholski et al., 2012; Hirose et al., 2015). In the peridotite composition, existing experimental studies provided conflicting results about the phase boundaries between Bm and PPv (Grocholski et al., 2012; Murakami et al., 2005; Ohta et al., 2008; Ono and Oganov, 2005).
Mid-mantle heterogeneities and iron spin transition in the lower mantle: Implications for mid-mantle slab stagnation
2017, Earth and Planetary Science LettersThe role of solid–solid phase transitions in mantle convection
2017, LithosCitation Excerpt :A review of numerical experiments that have evaluated the role of olivine phase transitions at transition zone depths can be found in (Christensen, 1995). More recently, (Tackley, 2012) and (Hirose et al., 2015) focused on the effects of phase transformations occurring in the deep lower mantle, while (Tackley, 2015) discussed the chemical layering induced by phase transitions in a compositionally differentiated mantle. ( Kirby et al., 1996) have summarized the effects of olivine and pyroxene disequilibrium transformations within the cold lithospheric mantle, although with particular emphasis on deep earthquakes and strain localization.