The Earth Contents

1. Structure

The core and the mantle make up almost all the mass of the Earth, yet have a simple composition

The composition of the core and mantle is based on a small number of metals (iron, magnesium and silicon) and is believed to be similar to that of meteorites. It is very different from that of the crust, which has a much wider range of elements.

  Meteorites Crust Igneous rock
Oxygen % 32.3 46.6 38.0
Iron % 28.8 5.0 5.2
Silicon % 16.3 27.7 35.6
Magnesium % 12.3 2.1 2.2
Aluminium % 1.4 8.1 8.3
Calcium % 1.3 3.6 3.7
Sodium % 0.6 2.8 2.9
Potassium % 0.1 2.6 2.7

What are the main constituents of the core and the mantle?