Some simple physical models for absolute plate motions
Some simple physical models for absolute plate motions
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绝对板块运动的一些简单物理模型
DOI：
10.1029/jb079i017p02557
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发表时间：
1974
影响因子：
--
通讯作者：
N. Sleep
中科院分区：
文献类型：
--
作者：
S. Solomon;N. Sleep
虽然地球板块的相对角速度是众所周知的，但相对于下地幔的速度和驱动力的性质却是未知的。我们从岩石圈整体上没有施加净扭矩的假设和一系列关于驱动板块运动的力的假设，计算了绝对速度场的几个解。力模型包括所有板块底部的粘性阻力(加上在山脊和海沟施加相同大小但对相邻板块施加相反符号的扭矩的任意力)，集中在大陆下方的阻力，集中反对下沉板块水平平移的阻力，下沉板块的重力拉力，以及这些的线性组合。这些模型通常给出的绝对板块速度与那些在一组热点提供固定参照系的前提下计算出来的速度非常相似。这消除了将对驱动力的任何重大贡献归因于这些热点的一些理由。从明显不同的驱动机制推断的板块运动的相似性，排除了使用速度场来区分所提出的模型的可能性。许多热点可能只是由于与作用在当前板块边界上的力有关的板内张应力所致。这表明，板内应力的计算最终可以用于在力模型中进行选择。
Although the relative angular velocities of the earth's plates are well known, the velocities relative to the underlying mantle and the nature of the driving forces are not. We calculate several solutions to the ‘absolute’ velocity field from the hypothesis that no net torque is exerted on the lithosphere as a whole and a series of assumptions about the forces driving plate motions. The force models include viscous drag at the base of all plates (plus arbitrary forces at ridges and trenches that exert torques of equal magnitude but opposite sign on adjacent plates), drag concentrated beneath continents, drag concentrated to oppose the horizontal translation of sinking slabs, gravitational pull by sinking slabs, and linear combinations of these. These models generally give absolute plate velocities that are very similar to those calculated on the premise that a set of ‘hot spots’ provides a fixed reference frame. This removes some of the rationale for attributing to these hot spots any significant contribution to the driving forces. The similarity of plate motions inferred from markedly different driving mechanisms precludes using the velocity fields to discriminate among proposed models. Many of the hot spots may be simply due to intraplate tensional stress associated with the forces acting on present plate boundaries. This suggests that calculation of intraplate stress can ultimately serve to choose among force models.