DOI: 10.1016/j.epsl.2018.08.050
Scopus记录号: 2-s2.0-85053205959
论文题名: Mantle kinematics driving collisional subduction: Insights from analogue modeling
作者: Pitard P. ; Replumaz A. ; Funiciello F. ; Husson L. ; Faccenna C.
刊名: Earth and Planetary Science Letters
ISSN: 0012821X
出版年: 2018
卷: 502 起始页码: 96
结束页码: 103
语种: 英语
英文关键词: analogue model
; continental subduction
; far field forces
; mantle drag
; slab pull
; Tibet
Scopus关键词: Buoyancy
; Lithology
; Oceanography
; Analogue modeling
; Continental subductions
; Far field
; Slab pull
; Tibet
; Tectonics
; analog model
; arc-continent collision
; continental lithosphere
; mantle structure
; plate tectonics
; slab
; subduction
; Tethys
; China
; Xizang
英文摘要: Since several decades, the processes allowing for the subduction of the continental lithosphere less dense than the mantle in a collision context have been widely explored, but models that are based upon the premise that slab pull is the prominent driver of plate tectonics fail. The India–Asia collision, where several episodes of continental subduction have been documented, constitute a case study for alternative views. One of these episodes occurred in the early collision time within the Asian plate where continental lithosphere not attached to any oceanic lithosphere subducted southward in front of the Indian lithosphere during its northward subduction that followed the oceanic subduction of the Tethys ocean. This process, known as collisional subduction, has a counter-intuitive behavior since the subduction is not driven by slab pull. It has been speculated that the mantle circulation can play an important role in triggering collisional subduction but a detailed, qualitative analysis of it is not available, yet. In this work we explore the southward subduction dynamics of the Asian lithosphere below Tibet by means of analogue experiments with the aim to highlight how the mantle circulation induces or responds to collisional subduction. We found that during the northward oceanic subduction (analogue of Tethys subduction) attached to the indenter (Indian analogue), the main component of slab motion is driven vertically by its negative buoyancy, while the trench rolls back. In the mantle the convective pattern consists in a pair of wide convective cells on both sides of the slab. But when the indenter starts to bend and plunge in the mantle, trench motion reverses. Its advance transmits the far field forces to two upper plates (Asian analogues). The more viscous frontal plate thickens, and the less viscous hinterland plate, which is attached to the back wall of the box, subducts. During this transition, a pair of sub-lithospheric convective cells is observed on both sides of the Asian analogue slab, driven by the shortening of the frontal plate. It favors the initiation of the backwall plate subduction. Such subduction is maintained during the entire collision by a wide cell with a mostly horizontal mantle flow below Tibet, passively advecting the Asian analogue slab. Experimental results suggest that once the tectonic far-field force related to the forward horizontal motion becomes dominant upon the buoyancy forces, trench advancing and the transmission of the tectonic force to the upper and backwall plates are promoted. This peculiar condition triggers the subduction of the backwall plate, despite it is light and buoyant. © 2018 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/109633
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: ISTerre (Institut des Sciences de la Terre), Université Grenoble Alpes, CNRS, Grenoble, F-38000, France; Dipartimento Scienze, Università degli Studi Roma TRE, Largo S. Leonardo Murialdo 1, Rome, 00146, Italy
Recommended Citation:
Pitard P.,Replumaz A.,Funiciello F.,et al. Mantle kinematics driving collisional subduction: Insights from analogue modeling[J]. Earth and Planetary Science Letters,2018-01-01,502