Continental Growth

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Continental Growth
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Continental Growth

• Most continents used to be smaller.
• Through tectonic processes, rock has been added
  to continents.

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Cratons

• Ancient continent core
• Older, most altered type of rock.
• Canadian Shield

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Cratons

• Shield
• made of igneous and metamorphic rock
• are in geologically stable areas
• Platform
• made of sedimentary rock
• sits on top of the shield

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3 Sources of Growth

• Deep Sea Sediment

• Oceanic plate is subducted, sediments may be
  scraped and left behind.
• Volcanic Rock
• Occur at subduction zones, sources of sediment
  add to expansion of continent.
• Terranes
• A lithospheric plate, that has been moved
  attached to edge of continent. Rocks fossils do
  not match those of neighboring terrane.