What Is the Lower Mantle?

The lower mantle, historically also known as the mesosphere, represents approximately 56% of Earth's total volume, and is the region from 660 to 2900 km below Earth's surface; between the transition zone and the outer core.

What is the lower mantle made of?

composition of Earth's interior

(1,800 miles), consists of the lower mantle, which is composed chiefly of magnesium- and iron-bearing silicates, including the high-pressure equivalents of olivine and pyroxene.

What is the role of the lower mantle?

The lower mantle is an important player in the geological action we see above the surface, such as earthquakes and volcanoes. The core heats the lower mantle, and the warm lava rises into the upper mantle. As the upper mantle cools, the lava spreads and falls back to the center of the earth.