tectonic plates

• What are tectonic plates?

  Slabs of the Earth's crust that float on top of the mantle
• How does continental crust differ from oceanic crust?

  Continental crust is thicker and less dense than oceanic crust
• What are plate margins?

  Where tectonic plates meet
• What are the three types of plate margins?

  1. Destructive

  • Plates move towards each other
  • Magma rises to the surface in volcanoes
  • Ocean trenches occur
  • Denser oceanic plate is subducted under continental plate

  
  

  1. Constructive

  • Plates move away from each other
  • Magma rises to fill the gap

  
  

  1. Conservative

  • Plates move sideways past each other
  • Plates move in the same direction at different speeds
• What happens at a destructive plate margin?

  Plates move towards each other, magma rises to the surface, and ocean trenches occur
• What occurs at a constructive plate margin?

  Plates move away from each other and magma rises to fill the gap
• What characterizes a conservative plate margin?

  Plates move sideways past each other or in the same direction at different speeds