Earth's Crust

The Earth's Crust

The boundary between crust and mantle - Moho Discontinuity - boundary defined by a contrast in seismic velocity.

Crust - less than 1% Earth's volume.

Oceanic Crust 

5km-10km thick - composed of basalt, gabbro and diabase. Relatively simple, composed mainly of mafic rocks (basalt) or sima (silicates). Thinner and less complex.

Denisty - 3.3grams per cubic centimetre.

More dense than continental.

Oldest - 200million years old.

Continental Crust

30km-50km thick - reaches 70km in places.

Composed of less…