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1·Much of the activity between the continental shelves takes place deep underwater at the mid-ocean ridges.

大部分的大陆架的活动发生在深水下的大洋洋底的海脊。

2·This is part of the system of mid-ocean ridges that form as the tectonic plates of the Earth's crust move apart-a process known as sea floor spreading.

印度洋脊是中大洋脊的一部分，中大洋脊是地壳分离的地球板块形成的。这一形成过程被称为海底扩张。

3·As the rocks cool from lava, for instance at the deep mid-ocean ridges where the earth's surface plates are formed, crystals line up with the direction of the magnetic field.

举例来说由熔岩冷却的而来的岩石，位于深深的海中央山脊的地方就形成了地球表面的板块，水晶晶体排列方向与磁场方向一致。