Download Plate Tectonics (Chap. 3)

Plate Tectonics
Earth structure:
Core: inner core solid (iron)
outer core liquid (iron)
Mantle: composed of Fe/Mg- rich silicates (olivine, pyroxene)
Crust: continental – 20–90 km thick (old)
Ocean crust- 5–10 km thick (young)
Lithosphere: crust + upper mantle = “Plates”
Asthenosphere: partially molten upper mantle
Mantle: convection due to radioactive heating
3 types of plate boundary;
Convergent : compression stress
Divergent: tensional stress
Transform: shearing stress
Passive continental margin: E. coast USA
Active margin: W. coast USA; W. coast S. America
Hot spots: within plate e.g. Hawaiian chain
Supercontinents : Pangaea (breakup 200 m.y. ago), Rodinia (breakup 600 my ago)
Wilson cycle: opening and closing of ocean basins
Rock cycle can be understood in context of plate tectonics
Modification of plate tectonic theory: Terrane accretion