The mantle is the layer of Earth that lies between the crust and the outer core. It is composed primarily of solid rock, but it is not completely rigid. Instead, it is constantly in motion, albeit very slowly. This movement is driven by convection currents, which are caused by the heat from the Earth's core. The mantle is also affected by the rotation of the Earth, which causes it to bulge out at the equator and flatten at the poles.

The temperature of the mantle varies from about 1,000 degrees Celsius at the top to about 3,700 degrees Celsius at the bottom. The pressure also increases with depth, from about 100 megapascals (MPa) at the top to about 140 GPa at the bottom.

The mantle is divided into two main regions: the upper mantle and the lower mantle. The upper mantle is about 670 km thick and is made up of a variety of rocks, including peridotite, pyroxenite, and eclogite. The lower mantle is about 2,900 km thick and is made up of denser rocks, such as bridgmanite and ferropericlase.

The mantle is a very important layer of the Earth. It plays a role in the movement of tectonic plates, the generation of earthquakes, and the formation of volcanoes. It is also the source of many valuable minerals, such as gold, silver, and copper.