Mid-mantle anisotropy: Elasticity of aluminous phases in subducted MORB
نویسندگان
چکیده
منابع مشابه
Sound velocities and elasticity of aluminous MgSiO3 perovskite: Implications for aluminum heterogeneity in Earth’s lower mantle
[1] Aluminum has been reported to have a remarkably strong effect on the thermoelastic properties of MgSiO3 perovskite. However, the sound velocities of aluminous MgSiO3 perovskite have not been previously measured, even though this phase likely dominates most of the chemistry in Earth’s lower mantle. Here we report the first sound velocity measurements on aluminous MgSiO3 perovskite using Bril...
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Observations of seismic anisotropy can offer relatively direct constraints on patterns of mantle deformation, but most studies have focused on the upper mantle. While much of the lower mantle is thought to be isotropic, several recent studies have found evidence for anisotropy in the transition zone and uppermost lower mantle (the mid-mantle), particularly in the vicinity of subducting slabs. H...
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The Earth’s transition zone has until recently been assumed to be seismically isotropic. Increasingly, however, evidence suggests that ordering of material over seismic wavelengths occurs there, but it is unclear what causes this. We use the method of source-side shear wave splitting to examine the anisotropy surrounding earthquakes deeper than 200 km in slabs around the globe. We find signific...
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[1] Measurements of source‐side splitting in S waves from events within the Tonga slab reveal anisotropy in the upper and mid‐mantle beneath the slab. We observed splitting for events originating at both upper mantle and transition zone depths. Anisotropic fast directions ( ) are trench parallel or sub‐parallel for both upper mantle and transition zone events. Delay times (dt) decrease with dep...
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The geological materials in Earth's lowermost mantle control the characteristics and interpretation of seismic ultra-low velocity zones at the base of the core-mantle boundary. Partial melting of the bulk lower mantle is often advocated as the cause, but this does not explain the nonubiquitous character of these regional seismic features. We explored the melting properties of mid-oceanic ridge ...
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ژورنال
عنوان ژورنال: Geophysical Research Letters
سال: 2011
ISSN: 0094-8276
DOI: 10.1029/2011gl047923