Layers of the Earth

The first of the seven layers is the Crust which covers a depth of 40 km from the earth surface.

The second, which is the Upper Mantle which lays between 40 km to 400 km deep.

The subsequent ones are;

Transition Region 400 – 650 km,

Lower Mantle 650 – 2700 km,

D' Layer 2700 – 2890 km,

Outer Core 2890 – 5150 km and

Inner Core 5150 – 6378 km.

The chemical composition of the earth varies from layer to layer but as a whole the earth is made up of 34.6 % iron, 29.5 % oxygen, 15.2 % silicon, 12.7 % magnesium, 2.4 % nickel, 1.9 % sulfur and 0.05 % titanium.