Characteristics of earth's levels

 

Crust

The Earth's crust ranges from 5-70 km (3.1-43.5 mi)6 in depth and is the outermost layer. The thin parts are the oceanic crust, which underlies the ocean basins (5-10 km) and are composed of dense igneous (mafic) magnesium-iron silicate rocks, such as basalt. The thicker crust is the continental crust, which is less dense and is composed of aluminum-potassium-sodium silicate (felsic) rocks, such as granite. The upper mantle together with the crust constitutes the lithosphere.

Terrestrial mantle 

The Earth's mantle extends to a depth of 2,890 km, making it the thickest layer on Earth.The mantle is divided into upper and lower mantle, which are separated by the transition zone.The lowest part of the mantle next to the core-mantle boundary is known as the d" layer.The pressure at the bottom of the mantle is ≈140 G Pa (1.4 M atm). The mantle is composed of silicate rocks that are rich in iron and magnesium relative to the overlying crust.

Core

The average density of the Earth is 5.515 g/cm³. Because the average density of the surface material is only about 3.0 g/cm³, we must conclude that denser materials exist within the Earth's core.