DOI: 10.1016/j.tecto.2021.228954
论文题名: The competing effects of olivine and orthopyroxene CPO on seismic anisotropy
作者: Bernard R.E. ; Schulte-Pelkum V. ; Behr W.M.
刊名: Tectonophysics
ISSN: 00401951
出版年: 2021
卷: 814 语种: 英语
英文关键词: Anisotropy
; Crystallography
; Seismology
; Competing effects
; Crystallographic preferred orientations
; Elastic tensors
; Mantle deformation
; Orthopyroxene
; Seismic anisotropy
; Upper mantle
; Olivine
; crystal structure
; crystallography
; elastic property
; olivine
; orthopyroxene
; peridotite
; seismic anisotropy
英文摘要: Orthopyroxene is the second most abundant mineral in the upper mantle and, like olivine, can form crystallographic preferred orientations (CPO) during mantle deformation that may influence mantle seismic anisotropy. Here we use a compilation of 21 peridotites in which both olivine and orthopyroxene CPOs are preserved to document the range of orthopyroxene CPO types and to explore their effects on seismic anisotropy of peridotites. In addition to four previously published orthopyroxene CPO types, this study establishes three new CPO types, two of which result in orthopyroxene fast axes aligned parallel to the lineation and the direction of mantle shear/flow. We calculate bulk elastic tensors for each sample from the measured olivine and orthopyroxene CPOs, and use those in turn to calculate Vp and Vs velocities and anisotropy percentages. In order to explore the relative influence of olivine and orthopyroxene on anisotropy, these properties were calculated for a range of possible modal percentages, from 100% olivine to 100% orthopyroxene. While the effect of orthopyroxene CPO appears to be a negligible influence on the orientation of bulk seismic fast axes, the presence of increasing orthopyroxene decreases the anisotropic signal overall. However, at very low olivine modal percentages, olivine and orthopyroxene can be mutually destructive, where the addition of olivine to a mostly orthopyroxene rock can actually decrease anisotropy. © 2021 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/170778
Appears in Collections: 气候变化与战略
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作者单位: Department of Geological Sciences, Jackson School of Geosciences, The University of Texas at Austin, Austin, TX, United States; Cooperative Institute for Research in Environmental Sciences and Department of Geological Sciences, University of Colorado Boulder, Boulder, CO, United States
Recommended Citation:
Bernard R.E.,Schulte-Pelkum V.,Behr W.M.. The competing effects of olivine and orthopyroxene CPO on seismic anisotropy[J]. Tectonophysics,2021-01-01,814