| DOI: | 10.1016/j.epsl.2018.05.030
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| Scopus记录号: | 2-s2.0-85047628304
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| 论文题名: | Plug flow in the Earth's asthenosphere |
| 作者: | Semple A.G.; Lenardic A.
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| 刊名: | Earth and Planetary Science Letters
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| ISSN: | 0012821X
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| 出版年: | 2018
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| 卷: | 496 | | 起始页码: | 29
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| 结束页码: | 36
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| 语种: | 英语
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| 英文关键词: | asthenosphere
; lithosphere
; plate tectonics
; rheology
; seismic anisotropy
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| Scopus关键词: | Elasticity
; Rheology
; Seismic prospecting
; Seismology
; Structural geology
; Tectonics
; Velocity
; asthenosphere
; Constant velocities
; lithosphere
; Plate-driving force
; Power-law dependences
; Power-law rheology
; Seismic anisotropy
; Seismic observation
; Shear flow
; asthenosphere
; Couette flow
; lithospheric structure
; mantle convection
; Pacific plate
; plate tectonics
; rheology
; seismic anisotropy
|
| 英文摘要: | Recent seismic observations, focused on mantle flow below the Pacific plate, indicate the presence of two shear layers in the Earth's asthenosphere. This is difficult to explain under the classic assumption of asthenosphere flow driven by plate shear from above. We present numerical mantle convection experiments that show how a power law rheology, together with dynamic pressure gradients, can generate an asthenosphere flow profile with a near constant velocity central region bounded above and below by concentrated shear layers (a configuration referred to as plug flow). The experiments show that as the power law dependence of asthenosphere viscosity is increased from 1 to 3, maximum asthenosphere velocities can surpass lithosphere velocity. The wavelength of mantle convection increases and asthenosphere flow transitions from a linear profile (Couette flow) to a plug flow configuration. Experiments in a 3D spherical domain also show a rotation of velocity vectors from the lithosphere to the asthenosphere, consistent with seismic observations. Global mantle flow remains of whole mantle convection type with plate and asthenosphere flow away from a mid-ocean ridge balanced by broader return flow in the lower mantle. Our results are in line with theoretical scalings that mapped the conditions under which asthenosphere flow can provide an added plate driving force as opposed to the more classic assumption that asthenosphere flow is associated with a plate resisting force. © 2018 Elsevier B.V. |
| Citation statistics: |
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| 资源类型: | 期刊论文
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| 标识符: | http://119.78.100.158/handle/2HF3EXSE/109792
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| Appears in Collections: | 影响、适应和脆弱性
气候变化事实与影响
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作者单位: | Department of Earth, Environmental and Planetary Sciences, Rice University, 6100 Main Street, Houston, TX 77005, United States
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| Recommended Citation: | |
Semple A.G.,Lenardic A.. Plug flow in the Earth's asthenosphere[J]. Earth and Planetary Science Letters,2018-01-01,496
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