The mantle is the largest part of the Earth. It is extremely hot and plastic. The Mantle is solid rock and is subdivided into upper mantle and lower mantle.
The Upper Mantle
The upper mantle contains 10.3 % of the Earth's mass. The upper mantle contains 15.3% of the mantle-crust mass. Olivine (Mg, Fe) and pyroxene (Mg, Fe) have been the primary minerals found in this way. Part of the upper mantle called the asthenosphere. It thins to a few kilometers at ocean spreading centres, thickens to about 100 -150 km under the older parts of ocean basins and is up to 250 - 300 km thick under continental shield areas. The upper mantle is made of peridotite and eclogite rock and extends from the Moho to a depth of 400km. The earth's crust and uppermost mantle together form the lithosphere. The lithosphere makes up the plates of plate tectonic theory. The lithosphere averages about 70 kilometers thick beneath continents. Lithosphere- this is the weak spot in the upper mantle that allows for intrusion and the shifting of plate. This information came from the University of Colorado.(Joe Smyth's) and http://www.geolsoc.org.uk/gs3lith.htm
| UPPER MANTLE | LOWER MANTLE | |
| EARTH' S MASS | 10.3 % | 49.2 % |
| MANTLE CRUST MASS | 15.3 % | 72.9 % |
The Lower Mantle
The lower mantle contains 49.2 % of the Earth's mass and is about 50% of the total mass of the planet. The lower mantle contains 72.9% of the mantle-crust mass and is composed of silicon, magnesium, oxygen, iron, calcium, and aluminum. The lower mantle extends from 670 to 2900km. The asthenosphere lies below the lithosphere and represent rock close to its melting point. This source of information came from http://spaceart.com/solar/eng/earthint.htm