Lithosphere

The lithosphere (from the Greek for "rocky" sphere) is the outer solid shell of the Earth. As the cooling surface layer of the Earth’s convective system, the lithosphere thickens over time. It is fragmented into relatively strong pieces, the plates, which move independently relative to one another. These lithospheric movements are described as plate tectonics. The lithosphere includes the crust and, below, the uppermost layer of the mantle; it floats on the weaker asthenosphere. There are two types of lithosphere:

• the oceanic lithosphere.
• the continental lithosphere.

Refer to Earth for detailed information on the interior of the planet.