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    Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/71631

    Title: 以參數化的低黏滯性楔型體在數值模型中生成單邊隱沒;Generating Single-sided Subduction with Parameterized Mantle Wedge
    Authors: 林君蓉;Lin,Chun-Jung
    Contributors: 地球科學學系
    Keywords: 單邊隱沒;Single-sided;subduction
    Date: 2016-08-05
    Issue Date: 2016-10-13 13:23:30 (UTC+8)
    Publisher: 國立中央大學
    Abstract: 地球上的隱沒帶為單邊隱沒;在隱沒帶中只有單一板塊隱沒到上覆板塊之下。然
    沒。在本研究中,我們將探討在數值模型 中設置低黏滯性地幔楔如何幫助生成單邊隱沒
    速度(Tan et al., 2002)
    、非牛頓流變性(Billen and Gurnis, 2001)或是自由表面(Geryaet
    al., 2008)
    度時,我們於其上方設置一個參數化的低黏滯性楔型體(Low viscosity wedge, LVW)
    以代表地幔楔(Manea and Gurnis, 2007)。
    助於形成板塊間的低黏滯性交界層(Low viscosity layer)。
    到板塊本身的厚度與黏滯性)對於隱沒速度也有極高的影響力。;Subduction on Earth is one-sided, where one oceanic plate sinks beneath the other.
    However, subduction zones in most numerical models tends to develop two-sided subduction,
    where both plates sink to the mantle. In this study, we use numerical model to find out how
    the existence of low viscosity wedge (LVW) can enable single-sided subduction and affects
    the flow in the subduction system. At the mantle wedge, water released from dehydrated
    oceanic crust serpentinized the mantle, which forms the LVW. LVW is an important part of
    the subduction system and provides efficient lubricant between the subducting slab and
    overriding lithosphere.
    Single-sided subduction can be generated in numerical models by different techniques,
    including prescribed plate velocity (Tan et al., 2002), non-Newtonian rheology (Billen and
    Gurnis, 2001), and free surface (Gerya et al., 2008). These techniques either requires
    kinematic boundary condition, which produces mantle flow inconsistent with the buoyancy, or
    costs great amount of computational resources when solving nonlinear equations. In this study,
    we tried to generate single-sided subduction with Newtonian viscosity and free slip surface. A
    set of tracers representing hydrated oceanic crust are placed near the surface. As the tracers
    subducted with the lithosphere, we assume that the oceanic crust becomes dehydrated and
    serpentinizes the mantle wedge above. A parameterized LVW is placed above the subducted
    tracers in the models. (Manea and Gurnis, 2007). We also decrease the viscosity of the
    hydrated oceanic crust to represent a low viscosity layer (LVL).
    We test with different upper and lower depth limits of the LVW and the viscosity of the
    LVW. Both overriding plate and subducting plate′s surface velocity relative to the trench is
    calculated in order to determine whether the subduction is single-sided.
    Results of our numerical models show that not only the LVW above the slab is essential
    for the formation of single-sided subduction, a LVL between the two tectonic plates is also
    needed to efficiently lubricate the plate interface after the subduction started. Additionally, the
    plate′s age, which effects the plate thickness and viscosity, strongly influence the speed of
    Appears in Collections:[地球物理研究所] 博碩士論文

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