Earth Structure
The earth is composed of four layers: the inner core, the outer core, the mantle and the crust. Each layer can be characterized by its distinctive composition and physical properties. Most of the heaviest elements are found closer to the center of the earth while the lighter elements tend to be concentrated closer to the Earth's surface.
Crust
- thin rigid layer of igneous, metamorphic and sedimentary rocks.
- made mainly of silicate minerals (light elements).
- thickness of oceanic crust 5 - 10 km, continental crust 30 - 40 km.
- plastic-like layer capable of flow.
- made of Fe-Mg silicate minerals.
- thickness about 2900 km.
- thick liquid.
- made of Fe and other elements.
- thickness about 2300 km.
- solid sphere.
- made of metals such as Fe and Ni.
- diameter 2400 km.
