The thickest layer of the Earth is called the mantle. It lies between the Earth’s crust and the outer core, extending to a depth of about 2,900 kilometers (1,800 miles) beneath the surface.
The mantle is composed of silicate rocks that are rich in iron and magnesium, and it accounts for approximately 84% of the Earth’s total volume. This layer is semi-solid and behaves like a fluid over long periods, which allows for the movement of tectonic plates.
Understanding the mantle is crucial because it plays a significant role in the geological processes that shape our planet, such as volcanic activity and plate tectonics. Its convective currents drive the movement of the crust above, resulting in earthquakes and the formation of mountain ranges.