DOI: 10.1016/j.tecto.2020.228659
论文题名: Dynamics of continental lithosphere extension and passive continental rifting from numerical experiments of visco-elasto-plastic thermo-chemical convection in 2-D Cartesian geometry
作者: Yoshida M. ; Saito S. ; Yoshizawa K.
刊名: Tectonophysics
ISSN: 00401951
出版年: 2020
卷: 796 语种: 英语
中文关键词: Continental breakup
; Continental lithosphere
; Continental rifting
; Numerical experiment
; Seafloor subsidence
; Thermo-chemical convection
英文关键词: Deformation
; Drag
; Elastoplasticity
; Lithology
; Cartesian geometry
; Continental break-up
; Continental lithosphere
; Continental margin
; Continental rifting
; Extensional stress
; High strain rates
; Numerical experiments
; Strain rate
; continental breakup
; continental lithosphere
; experiment
; extensional tectonics
; geometry
; mantle convection
; passive margin
; rifting
; strain
; subsidence
; two-dimensional modeling
英文摘要: In contrast to active continental rifting, which is caused by the thermal erosion of active upwelling plumes, passive continental rifting is attributed to the extensional stress acting on the continental lithosphere due to either the basal drag force exerted by the passive mantle flow under the lithosphere or the boundary forces at the continental margins. Although the extension of continental lithosphere by passive continental rifting may cause the breakup of continental margins, such as the separation of Zealandia from Gondwanaland at ca. 100 Ma and the Japanese islands from Eurasia at ca. 25 Ma, the dynamics have not been fully understood from geophysical and geological perspectives. Here, a series of numerical experiments of visco-elasto-plastic thermo-chemical convection with a free surface is performed using 2-D Cartesian models to investigate the localization of strain in the extending continental lithosphere, with an initial depth of 200 km, and the behavior of continental rifting and breakup. Our results demonstrate that when extension rates at the continental margin were set between 1 and 4 cm yr−1, the time taken for seafloor subsidence and subsequent continental breakup under extensional stress is less than a few million years. During continental rifting, high-shear zones (i.e., high-strain-rate zones) develop under the base of the deforming continental lithosphere, with a strain rate of the order of 10−13 s−1, which is approximately two orders larger than the typical value of the mantle interior. Due to accumulating strain along the base of the deforming lithosphere, excess strain is not concentrated on the shallowest part of the underlying mantle; hence, the spreading ridge that breaks the thick continental lithosphere emerges as a locally weak plate boundary on the Earth's surface. This characteristic is more remarkable as the activation volume of the sublithospheric mantle rock and the resultant viscosity are low under hydrous conditions. © 2020 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/170740
Appears in Collections: 气候变化与战略
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作者单位: Geophysical Research Group, Volcanoes and Earth's Interior Research Center, Research Institute for Marine Geodynamics, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15 Natsushima-cho, Yokosuka, 237-0061, Japan; Institute for Marine-Earth Exploration and Engineering, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15 Natsushima-cho, Yokosuka, 237-0061, Japan; Department of Earth and Planetary Sciences, Faculty of Science, Hokkaido University, Sapporo, 060-0810, Japan
Recommended Citation:
Yoshida M.,Saito S.,Yoshizawa K.. Dynamics of continental lithosphere extension and passive continental rifting from numerical experiments of visco-elasto-plastic thermo-chemical convection in 2-D Cartesian geometry[J]. Tectonophysics,2020-01-01,796