Describe the characteristics of oceanic crust. (AQA Past Paper, 3 marks)

There are two types of crust we need to know about: Oceanic crust and Continental crust. Oceanic crust is formed at mid ocean ridges where two plates pull apart. Here magma from the mantle upwells. When it reaches the surface it cools and solidifies to form oceanic crust. Oceanic crust is then destroyed at subduction zones where it is sinks beneath the continental crust. This subduction occurs because the oceanic crust is denser than that continental crust. This constant cycle of creation and destruction means that oceanic crust is much younger than continental crust, most oceanic crust is younger than 200 million years. The youngest material is found close to the mid ocean ridge where there plates are pulling apart.