Plate TectonicsBOUNDARIES
Chapter 17Learning Targets:
• What are the three types of plate boundaries?• What features can be found at each one?
Plate Tectonics
• Earth’s crust is cracked into smaller pieces called PLATES
• Looks like a cracked egg shell• There are two types of crust
– Continental crust– Oceanic crust
Plate Boundaries
• Divergent Boundary– Moving away
• Convergent Boundary– Moving together
• Transform Boundary– Sliding past each other
Plate Tectonics• Divergent Plate Boundaries
– Magma comes up pushing plates away – New rocks are created– Mid-Ocean Ridge = largest divergent
boundary• Underwater Mountain Range
– Called a Rift Valley if on land• Great Rift Valley in Africa
Watch Animation
Plate Tectonics• Divergent Boundary
– Plates are moving AWAY from each other
– I need 2 Volunteers!– DIVergent DIVorce
Plate Tectonics• Convergent Boundaries
– There are 2 main types of Convergent Boundaries
• First one is when an oceanic plate meets a continental plate
Oceanic – Continental Boundary
• Oceanic Crust is denser than Continental Crust
• Oceanic Crust gets SUBDUCTED underneath Continental Crust– Subduction goes underneath
• Creates a Trench and Volcanoes – Example: Mt. St. Helens
Watch Animation!
Continental – Continental Boundary
• Plates have same densities– No subduction
• Plates Collide and land goes UP• Mountains are created
– Paper Demo• Example: Himalayan Mountains
(Mt. Everest)
Plate Boundaries
• Convergent Boundaries– Plates moving TOWARDS each other– Need 2 more Volunteers!
– Convergent Connecting or COUPLE
Plate Boundaries• Transform Boundary
– A.k.a Sliding boundary– One plate is sliding horizontally past another
plate– Earthquakes are common at these
boundaries– The San Andreas Fault (California) is the
most well known example
Watch Animation
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