Relative importance of trenchward upper plate motion and friction along the plate interface for the topographic evolution of subduction-related mountain belts
Relative importance of trenchward upper plate motion and friction along the plate interface for the topographic evolution of subduction-related mountain belts
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上层板块向沟槽的运动和沿板块界面的摩擦对于俯冲相关山带地形演化的相对重要性
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发表时间：
2005
期刊：
影响因子：
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通讯作者：
A. Pfiffner
中科院分区：
文献类型：
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作者：
A. Hampel;A. Pfiffner
摘要我们提出的有限元模型，调查的相对重要性，两个向沟运动的上板块和板间耦合的发展，在会聚边缘的地形。通常，在模拟和实地研究中，都忽略了向海沟移动的大陆板块对地形生长的作用。相反，下行板块对大陆板块的作用力以及板块间的耦合作用被认为是导致上板块变形的原因。我们的模型设置包括一个大洋板块，它与大陆板块沿着摩擦板块界面接触，并由板块拉力驱动。两种岩石圈都具有弹粘塑性流变特性。这些模型表明，只有当上板块向海沟移动时，沿板块界面沿着的摩擦才能导致高地形。如果没有这种向海沟的推进，就不会产生高的地形，因为上板块由于俯冲板块施加的阻力而下沉。增加摩擦系数只会增大阻力并增加下沉量。我们的研究结果意味着，大陆板块的向沟运动起着关键作用的山脉带在会聚边缘的发展，大洋板块的俯冲，即使高板间耦合不能解释安第斯型造山带的形成。
Abstract We present finite-element models that investigate the relative importance of both trenchward motion of the upper plate and interplate coupling for the development of topography at convergent margins. Commonly, the role of a trenchward moving continental plate for the growth of topography is neglected in both modelling and field studies. Instead, forces exerted by the downgoing plate on the continental plate as well as interplate coupling are thought to be responsible for the deformation of the upper plate. Our model set-up includes an oceanic plate, which is in contact with a continental plate along a frictional plate interface and driven by slab pull. Both lithospheres have an elasto-visco-plastic rheology. The models demonstrate that friction along the plate interface can only lead to a high topography if the upper plate is moving toward the trench. Without such a trenchward advance, no high topography is generated, as the upper plate subsides owing to the drag exerted by the subducting plate. Increasing the coefficient of friction only amplifies the drag and increases the amount of subsidence. Our findings imply that trenchward motion of the continental plate plays a key role for the development of mountain belts at convergent margins; subduction of an oceanic plate even with high interplate coupling cannot explain the formation of Andeantype orogens.