How valid are dynamic models of subduction and convection when plate motions are prescribed?
How valid are dynamic models of subduction and convection when plate motions are prescribed?
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DOI：
10.1016/s0031-9201(98)00156-3
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发表时间：
1999-02-10
影响因子：
2.3
通讯作者：
Gurnis, M
中科院分区：
文献类型：
--
作者：
Han, LJ;Gurnis, M
在地幔对流模型中对完全动态板块公式和运动学板块公式进行了详细比较。板块速度是根据完全动态板块模型自洽计算的，该模型具有与温度和应力相关的粘度以及预先存在的移动断层。在完全动态模型中，现在仅由内部浮力驱动，而在运动学模型中，现在由规定的表面速度和内部浮力的组合驱动。仅与温度相关的粘度。接近从全动态模型确定的有效粘度，用于运动学模型。当有效粘度和表面速度几乎相同时，这两种类型的模型给出了非常相似的温度结构和板片演化历史。在运动板块模型中，由规定的速度边界条件引入的额外功显然在岩石圈内消散：并且对岩石圈下的对流影响很小。在具有周期性横向边界条件的模型中，板片以倾斜角度沉入下地幔，这与反射边界条件下发生的垂直下沉形成对比。模型表明，我们可以在周期性边界条件或反映边界条件下使用运动学模型来模拟完全动态模型。 (C) 1999 Elsevier Science B.V. 保留所有权利。
A detailed comparison between fully dynamic and kinematic plate formulations has been made in models of mantle convection. plate velocity is computed self-consistently from fully dynamic plate models with temperature- and stress-dependent viscosity and preexisting mobile faults. In fully dynamic models, the now is driven solely by internal buoyancy, while in kinematic models the now is driven by a combination of the prescribed surface velocity and internal buoyancy. Only a temperature-dependent viscosity. close to the effective viscosity determined from the fully dynamic models, is used in the kinematic models. The two types of models give very similar temperature structures and slab evolutionary histories when the effective viscosity and surface velocity are nearly identical. In kinematic plate models, the additional work introduced by the prescribed velocity boundary condition is apparently dissipated within the lithosphere: and has little influence on the convection under the lithosphere. In models with periodic lateral boundary conditions, slabs sink into the lower mantle at an oblique angle and this contrasts with the vertical sinking which occurs with reflecting boundary conditions. Models show that we can simulate Fully dynamic models with kinematic models under either periodic boundary conditions or reflecting boundary conditions. (C) 1999 Elsevier Science B.V. All rights reserved.