The Earths structure

The Earth has 4 layers:

• the crust
• the mantle
• the outer core
• the inner core

The Core:

• approx. the size of mars
• densest part of the planet
• made of rocks rich in iron and nickel
• a semi-molten outer core contains a solid inner core
• temperature over 6000'C
• surrounding the core is the mantle

The Mantle:

• surrounds the core
• composed of silicate rocks (iron and magnesium)
• most of the mantle is semi-molten (asthenosphere)
• temperatures near the core reaching 5000'C
• high temperature generate convection currents

The Crust:

• thinnest layer
• coolest least dense rocks

2 types of crust:

• Oceanic crust- 6-10km thick
• Continental crust- up to 70km thick

together the crust and the ridge of the upper mantle are known as the LITHOSPHERE