气候变化领域集成服务门户(CCPortal): The Water-Fe-Pressure dependent single-crystal elastic properties of wadsleyite: Implications for the seismic anisotropy in the upper Mantle Transition Zone

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DOI	10.1016/j.epsl.2021.116955
	The Water-Fe-Pressure dependent single-crystal elastic properties of wadsleyite: Implications for the seismic anisotropy in the upper Mantle Transition Zone
	Zhou W.-Y.; Ren Z.; Zhang J.S.; Chen B.; Hao M.; Ohuchi T.; Miyagi L.; Zhang D.; Alp E.E.; Lavina B.; Schmandt B.
发表日期	2021
ISSN	0012821X
卷号	565
英文摘要	Recent seismic studies suggested an anisotropic Mantle Transition Zone (MTZ) in areas adjacent to subducted slabs. Wadsleyite is the main anisotropy contributor in the upper MTZ, therefore the interpretation of these seismic observations requires the knowledge of single-crystal elastic moduli (Cijs) and the deformation-induced lattice preferred orientation (LPO) of wadsleyite. Wadsleyite can host up to 3 wt% water in its crystal structure as point defects in the form of hydroxyl groups, however, the combined effect of water content, Fe content, and pressure on the Cijs of wadsleyite remains unclear. In this study, we measured the high-pressure single-crystal elasticity of a synthetic hydrous Fe-bearing wadsleyite (0.14 (4) wt% water, Fe#=9.4, Fe3+/ΣFe=0.3) up to 18.2 (2) GPa. In combination with previous experimental data, we separated the effects of pressure, water, and Fe contents on the Cijs and intrinsic elastic anisotropy of wadsleyite. Our results suggest that the intrinsic elastic anisotropy of wadsleyite decreases with pressure, water, and Fe contents. At 15 GPa, increasing the water content by 0.1 wt% or Fe# by 1 decreases the VP and VS anisotropy of wadsleyite by ∼1.1-1.3%, and ∼0.8-1.3% in average, respectively. Combining the LPO determined in previous deformation experiments, we modeled the seismic anisotropy in the upper MTZ generated by a sub-vertical mantle flow near cold subducted slabs and a sub-horizontal mantle flow in the ambient mantle. In both scenarios, the LPO of wadsleyite leads to VSV (vertically polarized shear wave velocity) > VSH (horizontally polarized shear wave velocity). Our results suggest that wadsleyite may account for a weak anisotropic MTZ (<1%) on the global scale. Considering the fact that water decreases the elastic anisotropy but promotes LPO of wadsleyite, seismic anisotropy may not be a good water sensor in the upper MTZ. © 2021 Elsevier B.V.
关键词	elasticity Mantle Transition Zone seismic anisotropy wadsleyite water sensor
英文关键词	Acoustic wave velocity; Crystal orientation; Deformation; Elasticity; Seismology; Shear flow; Shear waves; Single crystals; Wave propagation; Elastic anisotropy; Fe content; Lattice preferred orientation; Mantle flow; Mantle transition zone; Seismic anisotropy; Shear wave velocity; Upper mantle; Wadsleyite; Water sensors; Anisotropy; crystal structure; crystallography; iron; mantle source; S-wave; seismic anisotropy; seismic velocity; transition zone; upper mantle; wadsleyite
语种	英语
来源期刊	Earth and Planetary Science Letters
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/203377
作者单位	Department of Earth and Planetary Sciences, University of New Mexico, Albuquerque, NM, United States; Institute of Meteoritics, University of New Mexico, Albuquerque, NM, United States; Hawaii Institute of Geophysics and Planetology, University of Hawai'i at Mānoa, Honolulu, HI, United States; Geodynamics Research Center, Ehime University, Matsuyama, Japan; Department of Geology and Geophysics, University of Utah, Salt Lake City, UT, United States; GeoSoiEnviroCARS, University of Chicago, Argonne National Laboratory, Argonne, IL, United States; Sector 3, Advanced Photon Source, Argonne National Laboratory, Argonne, IL, United States
推荐引用方式 GB/T 7714	Zhou W.-Y.,Ren Z.,Zhang J.S.,et al. The Water-Fe-Pressure dependent single-crystal elastic properties of wadsleyite: Implications for the seismic anisotropy in the upper Mantle Transition Zone[J],2021,565.
APA	Zhou W.-Y..,Ren Z..,Zhang J.S..,Chen B..,Hao M..,...&Schmandt B..(2021).The Water-Fe-Pressure dependent single-crystal elastic properties of wadsleyite: Implications for the seismic anisotropy in the upper Mantle Transition Zone.Earth and Planetary Science Letters,565.
MLA	Zhou W.-Y.,et al."The Water-Fe-Pressure dependent single-crystal elastic properties of wadsleyite: Implications for the seismic anisotropy in the upper Mantle Transition Zone".Earth and Planetary Science Letters 565(2021).