The crust and part of the upper mantle = lithosphere about 100 km thick Less dense than the material below it so it “floats” The interior structure of the earth The Lithosphere
The plastic layer below the lithosphere = asthenosphere The plates of the lithosphere float on the asthenosphere The interior structure of the earth The Asthenosphere
The interior structure of the earth The Crust Two types of crust: Continental Oceanic
Differences between oceanic crust and continental crust? Continental crust is composed of granite while the oceanic crust is composed of basalt. The density of the continental crust is less than the oceanic crust, thus it floats higher on the mantle.
In 1912 a German scientist named Alfred Wegener proposed the theory that the crustal plates are moving over the mantle. This was supported by fossil and rock type evidence; also matching of coastline shapes.