Gravity anomalies and convection currents: 2. The Puerto Rico Trench and the Mid-Atlantic Rise
Gravity anomalies and convection currents: 2. The Puerto Rico Trench and the Mid-Atlantic Rise
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重力异常和对流：2.波多黎各海沟和中大西洋海隆
DOI：
10.1029/jz070i024p06189
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发表时间：
1965
影响因子：
--
通讯作者：
W. J. Morgan
中科院分区：
文献类型：
--
作者：
W. J. Morgan
圆柱体沉入粘性流体表面的结果适用于地球，因为表面的垂直载荷相对独立于粘性随深度的变化。地表垂直负荷与地壳厚度有关，净自由空气异常是地壳各层的引力加上深沉的引力共同作用的结果。然后将为不同大小和深度的下沉计算的地壳厚度和自由空气异常与波多黎各海沟和大西洋中部隆起的测量自由空气异常和地震深度进行比较。在这两种情况下，驱动质量的最佳深度约为100公里。在波多黎各，驱动物质在这个深度非常集中；据推测，它的密度比这个深度的平均密度高5%到10%。在大西洋中部，驱动力更分散；它分布在数百公里的水平距离上，密度比平均密度低约1%。
The results found for a cylinder sinking beneath the surface of a viscous fluid are applicable to the earth, since the vertical load at the surface is relatively independent of the variation of viscosity with depth. The vertical surface load is related to the thickness of the crustal layers, and the net free-air anomaly is caused by the attraction of these crustal layers plus the attraction of the deep sinker. The crustal thickness and the free-air anomaly computed for sinkers of different sizes and depths are then compared with the measured freeair anomalies and seismic depths of the Puerto Rico trench and the mid-Atlantic rise. In both of these cases the driving mass has an optimum depth of about 100 km. In Puerto Rico the driving mass is very concentrated at this depth; it is inferred to be 5 to 10% more dense than the average density at this depth. In the mid-Atlantic the driving mass is more diffuse; it is spread over a horizontal distance of several hundred kilometers and is about 1% less dense than the average.