Plate tectonics A Layered Earth

Classifying the layers by composition Crust –Oceanic crust –Continental crust Mantle Core

Classifying the layers by physical properties Lithosphere Asthenosphere Mantle Core

Isostatic equilibrium –buoyancy Source of Internal heat –Radioactive decay Conduction convection

The Evidence for layering Earth quakes –Primary and secondary seismic waves –Shadow zones

Continental Drift –Pangaea –panthalassa

Seafloor spreading Subduction zones Plate tectonics

Plate Boundaries Divergent plate boundaries –mid Atlantic ridgemid Atlantic ridge Convergent plate boundaries Transform plate boundaries

Divergent plate boundaries Ocean – Ocean Continent - Continent

Convergent plate boundaries Ocean – Ocean –Island arcIsland arc Ocean – Continent Continent - Continent

Confirmation of Plate Tectonics Paleomagnetism Apparent Polar wandering Hot spots Atolls and Guyots Age and distribution of sediments Terranes