Texture development and elastic stresses in magnesiowűstite at high pressure

Tommaseo, Caterina E.; Devine, James M.; Merkel, Sébastien; Speziale, S.; Wenk, Hans‐Rudolf

doi:10.1007/s00269-005-0054-x

Cited by 31 publications

(25 citation statements)

References 57 publications

(68 reference statements)

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“…Orientations with {100} lattice planes perpendicular to the compression direction deform most easily and thus are most subject to recrystallization 25 . In MgO, like NaCl, room temperature compression yields a {100} maximum as a result of dominant {110}〈1-10〉 slip 3, 11,26 . Upon recrystallization the hard {111} orientations become depleted while the {100} maximum strengthens 24 .…”

Section: Resultsmentioning

confidence: 99%

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In situ laser heating and radial synchrotron x-ray diffraction in a diamond anvil cell

Kunz

Caldwell

Miyagi

et al. 2007

Review of Scientific Instruments

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Section: Resultsmentioning

confidence: 99%

“…The main reason was that deformation mechanisms of this cubic mineral with a simple diffraction pattern are reasonably understood 9, 10 and the material was studied previously with DAC in radial diffraction 11 . Also, elastic properties are well known.…”

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confidence: 99%

In situ laser heating and radial synchrotron x-ray diffraction in a diamond anvil cell

Kunz

Caldwell

Miyagi

et al. 2007

Review of Scientific Instruments

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“…With the silicate phase being the dominant interconnected phase in the lower mantle, it should strongly influence transport properties (34)(35)(36) and, most notably, viscosity (37). Although there are no compositional-dependence deformation data on Brg, experiments on olivine (38) and Fp (39) have shown an inverse correlation between iron content and strength: Minerals with higher iron concentrations are softer. Assuming that the strength of Brg/PPv follows a similar compositional dependence, an increase in K eff should result in decreased strength.…”

Section: +mentioning

confidence: 99%

Spin and valence dependence of iron partitioning in Earth’s deep mantle

Piet

Badro

Nabiei

et al. 2016

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

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We performed laser-heated diamond anvil cell experiments combined with state-of-the-art electron microanalysis (focused ion beam and aberration-corrected transmission electron microscopy) to study the distribution and valence of iron in Earth's lower mantle as a function of depth and composition. Our data reconcile the apparently discrepant existing dataset, by clarifying the effects of spin (high/low) and valence (ferrous/ferric) states on iron partitioning in the deep mantle. In aluminum-bearing compositions relevant to Earth's mantle, iron concentration in silicates drops above 70 GPa before increasing up to 110 GPa with a minimum at 85 GPa; it then dramatically drops in the postperovskite stability field above 116 GPa. This compositional variation should strengthen the lowermost mantle between 1,800 km depth and 2,000 km depth, and weaken it between 2,000 km depth and the D" layer. The succession of layers could dynamically decouple the mantle above 2,000 km from the lowermost mantle, and provide a rheological basis for the stabilization and nonentrainment of large low-shearvelocity provinces below that depth.iron partitioning | lower mantle | spin state | valence state | viscosity T he relative concentration (partitioning) of iron in minerals constituting mantle rocks is a critical parameter controlling their physical properties and, consequently, the dynamical properties of the mantle. In a pyrolitic mantle, the lower-mantle mineral phase assemblage consists of bridgmanite (Brg)-which transforms to postperovskite (PPv) at pressures higher than 110 GPa (1-4)-ferropericlase (Fp), and calcium silicate perovskite. Only Brg/PPv (hereafter referred to as "silicate" and abbreviated Sil) and Fp can accommodate significant amounts of iron in their structure (5). Density, elasticity, viscosity, and thermal or electrical conductivities, along with associated phase relations, melting temperatures, and relative melt/solid buoyancy, are all linked to the concentration, valence, and spin state of iron in lower-mantle minerals. The seismic observation of global-scale heterogeneities such as large low-shear-velocity provinces (LLSVPs) (6, 7), and that of experimental iron spin-pairing in mantle minerals at lower-mantle depths (8, 9), has fueled a number of investigations of iron partitioning in the lower mantle (10-22).Despite remarkable advances in experimental and analytical techniques in the last two decades (Supporting Information), stark discrepancies have been reported, depending on the composition of the starting material (San Carlos olivine vs. pyrolite) and differences in iron valence (Fe 2+ and Fe 3+ ). San Carlos olivine has a molar (Mg + Fe)/Si = 2 and contains only iron as Fe 2+, whereas pyrolite has a molar (Mg + Fe)/Si = 1.4, contains Ca and Al, and contains iron as Fe 2+ and Fe 3+ (23). Therefore, the parameters controlling iron partitioning in deep mantle conditions are complex (12), and hinder any attempts to infer largescale geophysical or geochemical consequences on the mantle.To disentangle vale...

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“…The addition of Fe into (Mg,Fe)O lowers the strength of the 001 compression textures with the apparition of a secondary maximum at 011 for large Fe contents [265]. This could be associated to a decrease of activity on 1 ⁄2<110>{110}, but also the fact that, as (Mg,Fe)O is more compressible than pure MgO, a larger portion of the strain is accommodated elastically.…”

Section: Figure 32mentioning

confidence: 99%

Dislocations and Plastic Deformation in MgO Crystals: A Review

et al. 2018

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This review paper focuses on dislocations and plastic deformation in magnesium oxide crystals. MgO is an archetype ionic ceramic with refractory properties which is of interest in several fields of applications such as ceramic materials fabrication, nano-scale engineering and Earth sciences. In its bulk single crystal shape, MgO can deform up to few percent plastic strain due to dislocation plasticity processes that strongly depend on external parameters such as pressure, temperature, strain rate, or crystal size. This review describes how a combined approach of macro-mechanical tests, multi-scale modeling, nano-mechanical tests, and high pressure experiments and simulations have progressively helped to improve our understanding of MgO mechanical behavior and elementary dislocation-based processes under stress.

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Texture development and elastic stresses in magnesiowűstite at high pressure

Cited by 31 publications

References 57 publications

In situ laser heating and radial synchrotron x-ray diffraction in a diamond anvil cell

In situ laser heating and radial synchrotron x-ray diffraction in a diamond anvil cell

Spin and valence dependence of iron partitioning in Earth’s deep mantle

Dislocations and Plastic Deformation in MgO Crystals: A Review

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