The two types of Earth's crust are oceanic crust and continental crust.
- Oceanic crust is thinner (about 5-10 km thick), denser, and mainly composed of mafic rocks such as basalt and gabbro. It is formed at mid-ocean ridges by partial melting of the mantle and is relatively young because it is continuously recycled through subduction. Oceanic crust floats lower on the mantle due to its higher density
- Continental crust is thicker (averaging about 30-50 km, but can be thicker in mountainous regions), less dense, and primarily composed of felsic rocks like granite, which are rich in silica and lighter elements such as potassium and sodium. It is older, more chemically complex (sometimes called tertiary crust), and floats higher on the mantle. Continental crust tends to crumple and fold rather than subduct when it collides with oceanic crust
In summary, oceanic crust is thin, dense, and basaltic, while continental crust is thick, less dense, and granitic. These differences influence their behavior in plate tectonics and the structure of Earth's surface.
