评论太长时间,所以我会发布在这里,但却远不是一个完整的答案。玄武岩不能成为大陆地壳,因为是不同的元素。冰岛主要由玄武岩岩石。(本文[80%][1])。这是由不同的材料比大陆壳。玄武岩的岩石也比花岗岩坚固和持久的,所以不太可能可以形成大陆地壳的冰岛火山喷发或任何类似的火山喷发。我最好的猜测是,冰岛将分开一段时间后,防止永久块土地的形成。花岗岩、大陆地壳的主要材料有更多的铝和钾。玄武岩,较重的东西,有更多的镁。[源][2]。 They are made from distinctly separate processes and material, so one can't simply be turned into the other. While I have no doubt that some mixing goes on within the earth's mantle, I don't believe a significant amount of new continental crust is regularly being formed because to form new crust, you would need free aluminum ready to bind with Oxygen and Silicates and I believe most of the aluminum has already done that. That's my layman's answer anyway. I'm open to being corrected. [1]: http://www.geoguiding.asia/Geology-Iceland/816 [2]: http://jersey.uoregon.edu/~mstrick/AskGeoMan/geoQuerry27.html