让我们首先澄清术语:# # #海沟*沟*,随着@bon中描述他们的回答,是形成构造板块移动* *向对方的* *,一个板块下俯冲。@bon也提供了启发性的插图。的德语词[海沟][1]* [Tiefseerinne][2] *(字面意思就是“深海槽”)。# # #裂谷或*地堑* *(地堑)[3]*或[裂谷][4],形成板块移动* *彼此远离* *和破碎的地壳下沉的一部分。下面的例子是来自维基百科。德国术语*地堑* *地堑*(字面意思就是“战壕”)。[![地堑][5]][5]现在我们知道的术语,我们可以看的中大西洋海脊。# # #大西洋中脊的大洋中脊一直由[海底传播][6]:板块漂移,充满岩浆的裂痕。由此产生的新的地壳温度比周围的旧材料,因此具有较高的浮力:它更容易建立高漂浮在岩浆下面,形成一个脊与冷,老,更大的材料。 You can see this beautifully in the second illustration that @bon has provided: The crust is not thicker under the rift, rather it floats up. So the ridge is a ridge, not a trench, but the rift valley along its length is not a trench either, but a *graben*: it has been formed by tectonic plates moving away from each other and parts of the separating ridge breaking off its edge and sinking into the rift. [1]: https://en.wikipedia.org/wiki/Oceanic_trench [2]: https://de.wikipedia.org/wiki/Tiefseerinne [3]: https://en.wikipedia.org/wiki/Graben [4]: https://en.wikipedia.org/wiki/Rift_valley [5]: https://i.stack.imgur.com/IAX87.png [6]: https://en.wikipedia.org/wiki/Seafloor_spreading