< p >其他答案已经很好:没有板块构造和水蚀允许物质堆积在一个地方,然后留在原地。地球上都是这样:板块热点,移动运输建立岩石,导致岩浆找到另一个出口几英里。夏威夷也往往是一个地方,你可以看到水侵蚀发生在一个相当壮观的。< / p > < p >还有另一个原因,尽管:地球构造板块不是很厚,海洋板块,例如,只有10 - 20公里厚。他们甚至弯下腰冰盖下就像在冰河时代(或者今天在南极洲)。This process is called "isostatic adjustment", and you can think of it as the plate just sinking down into the region below that consists of a (somewhat) liquid state of rock which just moves to the side. It's a bit like when you step onto an ice floe: it just sinks down a bit. If this already happens with an ice sheet 1000 meters thick, imagine what would happen if you piled 30 km of rocks on top of a plate: it would just keep sinking down. In essence, every time you'd erupt some more lava and put it on top, the plate along with the base of the mountain would sink down a bit further. Mountains don't tend to build up very high in this process. Why is this not happening on Mars? Because Mars is relatively small, and its interior has long cooled down to a degree where the crust (the solid part of the earth that on Earth consists of the tectonic plates) is vastly thicker: Many 100s of km thick, possibly all the way down to the core-mantle boundary. A result of this is that they can support vastly larger loads without crumbling or sinking into the more liquid layer beneath. As a result, they crust on Mars can support mountains that the plates on Earth could not.