Single-crystal elasticity of MgAl2O4-spinel up to 10.9 GPa and 1000 K: Implication for the velocity structure of the top upper mantle

Duan, Yunfei; Li, Xinyang; Sun, Ningyu; Ni, Huaiwei; Tkachev, Sergey N.; Mao, Zhu

doi:10.1016/j.epsl.2017.10.014

Cited by 13 publications

(28 citation statements)

References 67 publications

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“…In the field of Earth Sciences, the MgAl 2 O 4 -spinel is a significant rock-forming mineral and an important component in the Earth’s crust and shallow mantle. Its physical, thermal, and other properties should to some extent influence the properties of the top upper mantle [12]. Its compositional features can provide important petrogenetic indications, playing important roles in some thermometrics and barometries and so on [13,14,15,16].…”

Section: Introductionmentioning

confidence: 99%

Kinetics and Thermodynamics of Mg-Al Disorder in MgAl2O4-Spinel: A Review

Liu

2019

Molecules

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The MgAl2O4-spinel has wide applications in various industries and in geosciences. It shows a significant inter-site Mg-Al cation exchange (denoted by the inversion parameter x), which modifies structural features, such as the unit-cell parameters and the sizes of the component polyhedra, and influences the physical and chemical properties. Previous studies mainly focused on the kinetics and thermodynamics of the Mg-Al exchange reaction, with the aim to ascertain the correlation between the inversion parameter and temperature; these studies, however, reached conflicting results. Here, we first reviewed the kinetics studies on the Mg-Al cation exchange reaction, and then reviewed all thermodynamic experiments, with special attention paid to the Mg-Al cation exchange equilibrium and the quench process, which might have modified the cation distributions once attained at high temperatures. We also assessed the accuracies in the temperature measurements and in the quantifications of the x by different analytical methods. With some necessary temperature correction and data removal, we have landed with a generally reliable x-T dataset covering the T-x space of 873 < T < 1887 K and 0.18(1) < x < 0.357(60) (71 data pairs in total). Fitting these x-T data to three most commonly used thermodynamic models, we have obtained more accurate model parameters. Further, we also evaluated the constituent items of the Gibbs free energy for the Mg-Al cation exchange reaction with experimental results from different research fields and reached the conclusion that highly possibly the T Δ S D should not be neglected. Based on this review, we suggest that: (1) Further kinetics study on the Mg-Al exchange reaction should be performed at both low T (<~973 K) and high T (>~1173 K); (2) further Mg-Al exchange equilibrium studies should be carried out at relatively low T and ambient P, as well as in vast ranges of simultaneous high P and high T; and (3) direct experimental measures about the entropies or the enthalpies of the MgAl2O4-spinels disordered to different extents should be conducted with full characterization of the starting materials and detailed description of the experimental procedures.

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Section: Introductionmentioning

confidence: 99%

Kinetics and Thermodynamics of Mg-Al Disorder in MgAl2O4-Spinel: A Review

Liu

2019

Molecules

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“…The densities of the bulk rock were averaged from the densities of each mineral weighted by their volume proportions. The elastic stiffness of the single-crystal (Cij) Amp (kataphorite), Opx (enstatite80), Phl, Pl (albite), and Sp were adopted from Brown and Abramson [49], Webb and Jackson [50], Alexandrov and Ryzhova [51], Brown et al [52], and Duan et al [53], respectively. Because Omp in MEC and FEC has the composition of Jd20-40Di50-75 [42], the (Cij) of the Omp that has a similar composition (Jd30Di70) recently reported by Hao et al [54] is used.…”

Section: Seismic Property Calculationmentioning

confidence: 99%

Seismic Properties of a Unique Olivine-Rich Eclogite in the Western Gneiss Region, Norway

Cao

Jung

2020

Minerals

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Investigating the seismic properties of natural eclogite is crucial for identifying the composition, density, and mechanical structure of the Earth’s deep crust and mantle. For this purpose, numerous studies have addressed the seismic properties of various types of eclogite, except for a rare eclogite type that contains abundant olivine and orthopyroxene. In this contribution, we calculated the ambient-condition seismic velocities and seismic anisotropies of this eclogite type using an olivine-rich eclogite from northwestern Flemsøya in the Nordøyane ultrahigh-pressure (UHP) domain of the Western Gneiss Region in Norway. Detailed analyses of the seismic properties data suggest that patterns of seismic anisotropy of the Flem eclogite were largely controlled by the strength of the crystal-preferred orientation (CPO) and characterized by significant destructive effects of the CPO interactions, which together, resulted in very weak bulk rock seismic anisotropies (AVp = 1.0–2.5%, max. AVs = 0.6–2.0%). The magnitudes of the seismic anisotropies of the Flem eclogite were similar to those of dry eclogite but much lower than those of gabbro, peridotite, hydrous-phase-bearing eclogite, and blueschist. Furthermore, we found that amphibole CPOs were the main contributors to the higher seismic anisotropies in some amphibole-rich samples. The average seismic velocities of Flem eclogite were greatly affected by the relative volume proportions of omphacite and amphibole. The Vp (8.00–8.33 km/s) and Vs (4.55–4.72 km/s) were remarkably larger than the hydrous-phase-bearing eclogite, blueschist, and gabbro, but lower than dry eclogite and peridotite. The Vp/Vs ratio was almost constant (avg. ≈ 1.765) among Flem eclogite, slightly larger than olivine-free dry eclogite, but similar to peridotite, indicating that an abundance of olivine is the source of their high Vp/Vs ratios. The Vp/Vs ratios of Flem eclogite were also higher than other (non-)retrograded eclogite and significantly lower than those of gabbro. The seismic features derived from the Flem eclogite can thus be used to distinguish olivine-rich eclogite from other common rock types (especially gabbro) in the deep continental crust or subduction channel when high-resolution seismic wave data are available.

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“…17−−23 Only a few reports on the disordered crystal structure and intrinsic properties of alumina-rich spinel have been published. 24,25 For the investigation of the crystal structure and elastic properties of alumina-rich spinel, a series of theoretical simulations based on density functional theory have been developed previously 26 but an experimental study has been lacking until now.…”

Section: Introductionmentioning

confidence: 99%

“…Fully dense alumina-rich spinel polycrystalline ceramics showing excellent optical transparency, mechanical properties, and thermal and chemical stability can compare with those of (Mg)AlON ceramics and sapphire single crystals as important transparent materials. , In the past several decades, most of the effort has been spent on the fabrication, processing, sintering, and material properties of alumina-rich spinel ceramics. ,, The evaporation of the magnesia component and alumina precipitates at high temperatures make it difficult to grow a nonstoichiometric spinel single crystal. − − Only a few reports on the disordered crystal structure and intrinsic properties of alumina-rich spinel have been published. , For the investigation of the crystal structure and elastic properties of alumina-rich spinel, a series of theoretical simulations based on density functional theory have been developed previously but an experimental study has been lacking until now.…”

Section: Introductionmentioning

confidence: 99%

Elasticity of Nonstoichiometric Alumina-Rich Spinel Determined by Bond Valence Theory and Brillouin Scattering

Wang

et al. 2022

Inorg. Chem.

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An accurate knowledge of the elastic properties of materials is essential for material science and engineering applications. Four single crystals of nonstoichiometric alumina-rich spinel [Mg 1−x Al 2(1+x/3) O 4 ] were obtained from sintered transparent ceramics for the investigation of its elastic properties. The disordered crystal structures were fully resolved by combining single-crystal structure refinement and a quadratic programming approach for the first time. The bond valence model and Brillouin scattering experiments were used to evaluate the bulk modulus (K), shear modulus (G), Young's modulus (E), and Poisson's ratio. The discrepancy between the theoretical and experimental results is <2.6%. The independent elastic constants (C 11 , C 12 , and C 44 ) were determined from Brillouin scattering experiments. A negative Poisson's ratio, υ(110, 11̅ 0), was found to exist in all alumina-rich spinels, which means it is a partially auxetic material. Blackman diagram analysis was introduced to identify the interrelationships and trends in mechanical and bonding properties in alumina-rich spinels. The bond valence model was suggested to be an effective and accurate approach for predicting the elastic modulus of spinels, which provides a useful tool for the study of the composition− structure−property relationship of materials.

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Single-crystal elasticity of MgAl2O4-spinel up to 10.9 GPa and 1000 K: Implication for the velocity structure of the top upper mantle

Cited by 13 publications

References 67 publications

Kinetics and Thermodynamics of Mg-Al Disorder in MgAl2O4-Spinel: A Review

Kinetics and Thermodynamics of Mg-Al Disorder in MgAl2O4-Spinel: A Review

Seismic Properties of a Unique Olivine-Rich Eclogite in the Western Gneiss Region, Norway

Elasticity of Nonstoichiometric Alumina-Rich Spinel Determined by Bond Valence Theory and Brillouin Scattering

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