tectonic plates

• what are the two types of plates?


  Oceanic and continental.
• what is the continental crust?


  Thicker, less dense part of Earth's crust.
• what is the oceanic crust?

  thinner and more dense
• why do plates move?

  because of convection currents in the mantle
• what do we call the places where plates meet?

  plate margins or boundaries
• what are the three types of plate margin?


  destructive, constructive & conservative
• what are destructive plate margins?

  • plates move towards eachother
  • oceanic plate gets subducted - creates magma
  • two continual meet and the ground is folded upwards - creating mountains
• what are constructive plate margins?

  • two plates move away from each other
  • magma rises from the mantle
  • fills gap and creates new crust

  
• what are conservative margins?

  • two plates move sideways
  • or moving same direction but diff speeds
  • crust isn't created or destroyed

  
• what is magma?


  molten rock found beneath the earths surface
• mantle


  the area underneath the crust which contains magma
• plate margin 


  the point at which two plates meet
• pressure belt


  a region of the earth which is generally under the same pressure
• subduction 


  a process that occurs at a destructrive plate margin when as plate is pushed below another plate, forcing it to sink into the mantle
• tectonic plates


  large slabs of the earths crust that sit and move on top of the liquid mantle
• Give three pieces of evidence to

  support the theory of plate tectonics.

  • The same types of fossilised plants and

  animals are found in South America and

  Africa;

  • The west coast of South America fits the east

  coast of Africa like a jigsaw puzzle;

  • Rock formations and mountain chains match

  in South America and Africa;