About the Earth's mantle, guys and gals....?

Question

The Earth's mantle consists of two layers. I want to know the composition of each layer. Or rather, the distinguishing compositions of each layer.
Please, can you help me?

Answer 1

The uppermost mantle just below the crust is composed of relatively cold and therefore strong material. This strong layer of mantle and the crust forms the lithosphere, and cools mainly by convection.
The subregion of the mantle extending about 250 km (155 mi) below the lithosphere is called the asthenosphere, this cools mainly by convection.
Typical mantle rocks have a higher portion of iron and magnesium, a higher magnesium to iron ratio, and a smaller portion of silicon and aluminium than the crust.
In the upper mantle, the silicates are generally solid (localised regions with small amounts of melt exist); however, as the upper mantle is both hot and under relatively little pressure, the rock in the upper mantle has a relatively low viscosity. In contrast, the lower mantle is under tremendous pressure and therefore has a higher viscosity than the upper mantle.