Theory of Plate Tectonics By: Ms. R. Wallace, WFHS

Layers to Earth

Plates! The Earth’s crust is made up of plates which move across the surface of the planet. This moves the continents and oceans with them.

What causes plate tectonics? Convection Currents: Differences in density cause hot plastic like rock in the asthenosphere to be forced upward toward the surface The lithosphere is carried with it When it cools, it sinks into the mantle and takes the crust with it. https://www.youtube.com/watch?v=MmMX83diwl0 Activity INSIDE the earth causes changes to the OUTSIDE 

Convection Current Video https://www.youtube.com/watch?v=ryrXAGY1dmE

Movement

Convergent Boundaries Oceanic-continental convergence

Subduction Zones The area when one plate moves underneath another in a convergent boundary

Divergent Boundary

Transform Boundary

Summary! Boundary type Movement Feature Formed Examples on Earth Divergent boundary Move apart; divide Rift Valley (on land), New ocean floor, Mid ocean ridges Mid-Atlantic Ridge, East African Rift Valley Red Sea Convergent boundary Continental-Continental collision Folded Mountains Earthquakes Appalachian Mts, Himalayan Mts Continental-Oceanic collision Volcanic Mts, Deep sea trenches, Deep Earthquakes Cascade Mts (Mt Saint Helens) Andes Mts Oceanic-Oceanic collision Volcanic island arcs, earthquakes, Japan, Philippines, Aleutian islands Transform Fault boundary Sliding/grinding past Fault zones Shallow Earthquakes San Andreas Fault

Diver between plates! https://www.youtube.com/watch?v=x__Ns2P3-jU

Hot Spots! Hot Spot: Hot magma rises through the mantle and pushes through a plate. This creates volcanoes and can create islands. The hotspot does not move, but the crust does, pulling islands away from the hotspot to form new islands. https://www.youtube.com/watch?v=bYv6V5EJAKc