Plate tectonic theory

Plate tectonic theory

1. structure

   • inner core
     • solid ball
       • also iron and nickel
     • density-13.6g/cm3
   • outer core
     • semi molten
       • iron and nickel
     • denisty-10-12g/cm3
   • mantle
     • solid and containing lower density material
       • Peridotite-formed of silicate rocks
   • crust
     • Solid and divided into two main types
       • oceanic crust
         • 5-9km thick
         • 3.0g/cm3 dense
         • basalt
         • slilica and magnesium
           • sima
       • continental crust
         • 30-70km
         • 2.7g/cm3
         • granite
         • silica and aluminuim
           • sial