现在的地球的表面由6大板块和9个小板块覆盖着。这些板块被称为洋中脊的海底山脉所分离,板块在洋中脊附近向两边移动,到达大陆附近时,在大陆边缘的海沟处又沉入另一个板块的下面。板块上的大陆则伴随着这种板块的活动而移动。这是上个世纪60年代末提出的“板块构造理论”的主要 The surface of the earth now covered by 6 large plates and 9 small plates. These plates are separated by a submarine ridge called mid-ocean ridge. The plate moves to both sides near mid-ocean ridge. When it reaches the mainland, it plunges into the sea below the other plate at the continental margin. The continent on the plate moves with the activity of this plate. This is the main “plate tectonics theory” put forward in the late 1960s