Plate Tectonics

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Plate Tectonics
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Earths Layers
Mantle

• Earth is made up of 4 main layers
• Inner core
• Outer core
• Mantle
• Crust (where we live

Outer core
Inner core
Crust
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What are tectonic plates made of?

• made of rigid lithosphere (crust upper mantle)
• Below plates lie asthenosphere

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Plate Movement

• plates move by underlying hot mantle convection
  cells

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What happens at tectonic plate boundaries?
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1. Divergent Boundaries

• Ex Mid-ocean ridges
• plates move apart, new material erupts to fill gap

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1. Divergent Boundaries

• Ex Iceland

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2. Convergent Boundaries
(continent-continent)
Continent-Continent Collision

• Forms mountains, ex Alps, Himalayas
• earthquakes

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2. Convergent Boundaries
(continent-oceanic)
Continent-Oceanic Crust Collision

• Called SUBDUCTION- oceanic slides under
  continental (volcanic mts trench)
• earthquakes

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2. Convergent Boundaries
(oceani-oceanic)
Ocean-Ocean Plate Collision

• 1 plate runs over the other causing it to sink
  into the mantle forming a subduction zone .
• a trench.
• Ex Mariana Trench is 11 km deep!
• Deepest part on planet
• -earthquakes

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3.Transform Boundaries
Transform Boundaries

• Where plates slide past each other
• earthquakes

Above View of the San Andreas transform fault
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Hotspots (not at plate boundaries)
What are Hotspot Volcanoes?

• Hot mantle plumes breaching the surface in the
  middle of a tectonic plate
• Hawaiian Islands

Photo Tom Pfeiffer / www.volcanodiscovery.com
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The tectonic plate moves over a fixed hotspot
forming a chain of volcanoes.
The volcanoes get younger from one end to the
other.