1 High - pressure Raman spectroscopic studies of hydrous wadsleyite II
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چکیده
منابع مشابه
High-pressure Raman spectroscopic study of Fo90 hydrous wadsleyite
Raman spectra of monoclinic Fo90 hydrous wadsleyite with 2.4 wt% H2O have been measured in a diamond-anvil cell with helium as a pressure-transmitting medium to 58.4 GPa at room temperature. The most intense, characteristic wadsleyite modes, the Si–O– Si symmetric stretch at 721 cm 1 and the symmetric stretch of the SiO3 unit at 918 cm , shift continuously to 58.4 GPa showing no evidence of a f...
متن کاملElasticity of hydrous wadsleyite to 12 GPa: Implications for Earth’s transition zone
[1] Knowledge of the pressure effect on elasticity of hydrous olivine polymorphs is necessary to model seismic wave speeds for potential hydrous regions of the mantle. Here we report single-crystal elastic properties of wadsleyite, b-Mg2SiO4, with 0.84 wt.% H2O measured to 12 GPa by Brillouin scattering. Pressure derivatives of the aggregate bulk modulus, KS0, and shear modulus, G 0 0, of hydro...
متن کاملWadsleyite II: A new high pressure hydrous phase in the peridotite-H2O system
A new hydrous silicate phase with formula Mg1.71Fe0.177Al0.01Si0.965H0.332O4 has been synthesized at 1400°C and 17.5GPa from a hydrous iron-rich mantle peridotite composition. The space group is Imma and unit cell parameters a = 5.6884(4); b = 28.9238(15); and c = 8.2382(6)Å, so that a and c are approximately those of wadsleyite, whereas b is 2.5 times that of wadsleyite. The calculated density...
متن کاملEffect of hydration on the single-crystal elasticity of Fe-bearing wadsleyite to 12 GPa
The single-crystal elastic properties of Fe-bearing wadsleyite with 1.93 wt% H2O (Mg1.634Fe0.202H0.305SiO4) have been determined by Brillouin scattering. At ambient conditions, the aggregate bulk and shear moduli (KS0, G0) of this wadsleyite are 156.2(5) and 98.0(3) GPa, respectively. Compared to the corresponding anhydrous wadsleyite, 1.93 wt% H2O lowers KS0 and G0 by 8.1% and 9.3%, respective...
متن کاملForsterite, hydrous and anhydrous wadsleyite and ringwoodite (Mg2SiO4): 29Si NMR results for chemical shift anisotropy, spin-lattice relaxation, and mechanism of hydration
We present a detailed 29Si NMR spectroscopic study of isotopically enriched samples of forsterite and of anhydrous and hydrous wadsleyite and ringwoodite (α, β, and γ phases of Mg2SiO4), which complement previous extensive studies of these minerals by XRD and vibrational spectroscopy. VISi is not detected in any of the phases at levels of about 0.1 to 0.5%. When coupled with recent theoretical ...
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