洋壳扩张的模式

洋壳扩张是地幔体积变化的结果,地幔体积增加的原因是地球内部固体物质态变,地幔体积减少的原因则是地球内部液态物质排放。洋壳扩张过程可分为扩张和顶置两个阶段:扩张阶段是地壳张性运动的时期,顶置阶段是地壳挤压性运动的时期,即洋壳的俯冲期。洋壳扩张的速度与地球内部物质态变速度相关,扩张的宽度与海水的温度相关,扩张带热液流的温度与洋壳扩张的速度相关,扩张带的洋脊地势与地幔上部同密度层的厚度相关。

The Model for Oceanic Crust Expansion

Oceanic crust expansion is the result of the mantle voluminal variation. The factor influencing the increment of the mantle volume lies in variation of the solid substance's phase state, while the emission of the liquid substance in the interior of the earth leads to the reduction of the mantle's volume. The oceanic crust expansion can be divided into the expansion stage or the period of extensional movement of the earth crust and the uplift-emplacement stage or the period of compressional movement of it (i.e. subduction period of the oceanic crust). The rate of the oceanic crust expansion relates to the velocity of the substantial phase state variation in the inner earth; the width of the expansion relates to the temperature of the sea water; the temperature of hydrothermal fluid in oceanic crust expansion zone relates to the rate of expansion of its own; the sea ridge of the expansion zone relates to the thickness of the same density layer on the upside of the earth mantle.