Propagation and linkage of oceanic ridge segments
Propagation and linkage of oceanic ridge segments
复制标题
大洋脊段的传播和连接
DOI：
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发表时间：
1984
期刊：
影响因子：
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通讯作者：
A. Aydin
中科院分区：
文献类型：
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作者：
D. Pollard;A. Aydin
我们已经研究了扩展脊的传播和发展的结构，连接脊段使用脊和弹性板裂纹之间的类比。计算了脊向对方传播的梯形脊段的脊传播力和控制传播方向的路径因子。脊传播力随着脊端部的接近而增加，但随着端部的通过而急剧下降，因此脊段可能会有些重叠。路径因子的符号随着脊端的接近和通过而改变，因此重叠脊端可能会分开，然后按照钩形路径会聚。计算了板平面内的剪应力大小和相邻脊段之间的最大剪切面方向，以研究转换断层。对于不同的加载条件模拟脊推，板拉，和脊吸，我们确定了一个区域的强烈的机械相互作用相邻的脊端部的应力集中。在所有条件下，相互作用带的剪应力随着两端的接近而增加，并随着两端的重叠而保持较大;因此，该带的地壳可能会破裂和弱化，为形成贯通的转换断层做准备。当端部通过时，计算的剪切平面朝向与脊的走向成约90°的方向旋转，从而有利于脊和变换的正交布置。还计算了板平面内的平均应力大小和主应力面的方向。在相互作用区的平均应力是拉伸的，因此除了在脊推荷载的情况下，可能会在那里形成盆地。最大张力作用的平面是斜向山脊的，因此有利于斜向的正断层界定转换谷。
We have investigated the propagation of spreading ridges and the development of structures that link ridge segments using an analogy between ridges and cracks in elastic plates. The ridge-propagation force and a path factor that controls propagation direction were calculated for echelon ridge segments propagating toward each other. The ridge-propagation force increases as ridge ends approach but then declines sharply as the ends pass, so ridge segments may overlap somewhat. The sign of the path factor changes as ridge ends approach and pass, so the overlapping ridge ends may diverge and then converge following a hook-shaped path. The magnitudes of shear stresses in the plane of the plate and orientations of maximum shear planes between adjacent ridge segments were calculated to study transform faulting. For different loading conditions simulating ridge push, plate pull, and ridge suction, we identify a zone of intense mechanical interaction between adjacent ridge ends in which stresses are concentrated. For all conditions, the shear stress in the interaction zone increases as ends approach and remains large as the ends overlap; thus crust in this zone may fracture and weaken in preparation for the formation of a through-going transform fault. The calculated shear planes rotate toward an orientation about 90° from the strike of ridges as the ends pass, thus favoring the orthogonal arrangement of ridges and transforms. The magnitudes of mean stresses in the plane of the plate and orientations of principal stress planes were also calculated. The mean stress is tensile in the interaction zone, so basins may form there, except in the case of ridge push loading. The planes across which the maximum tension acts are oblique to ridges, thus favoring obliquely oriented normal faults bounding the transform valley.