The mantle is about 1,800 miles (2,900 kilometers) thick and appears to be divided into two layers: the upper mantle and the lower mantle. The boundary between the two lies about 465 miles (750 ...

The mantle is the thick layer of rock between the planet's crust and core. It is about 1,800 miles deep and is mainly composed of silicate minerals rich in magnesium and iron. For the most part ...