Plate Tectonics

• Plate Tectonic Theory - The Earth's outermost layer (lithosphere) broke into separate sections called plates.

• Plate tectonics - The movement of plated and the activity inside the Earth.

  • cause volcanoes, earthquakes, and mountain building

Movement of Tectonic Plates

• Divergent plates - two plates move away from each other

• Convergent plates (Subduction zone)- one plate moves under another and sinks into the mantle

  • Subduction - happens when one plate is denser than the other

  • Oceanic crust - high density

  • Continental crust - low desity

• Convergent plates - plates push toward each other forcing upward movement and mountain building

• Transform plates - plates slide along beside each other in opposite directions

  • generates little volcanic activity (no gap between the plates)