Geography- Restless Earth- Water on land-Coastal zone

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  • Created by: helloello
  • Created on: 22-05-16 14:03

Restless Earth

  • Inner core- The centre of the Earth. Made of hot solid rock
  • Mantle- Hot molten rock called magma
  • Crust- Surrounds the mantle
  • Continental crust- light and 30km thick 
  • Oceanic crust- very dense and 5km thick

The crust is split into many plate (tectonic plates), all different shapes and sizes, convection currents within the mantle causes the plates to move.

Plate boundaries

Destructive plate margin

  • Plates move closer together
  • Dense oceanic crust is forced below the continetal crust 
  • Subduction zone is where the oceanic plate melts into the mantle
  • forms composite volcanoes

Examples: Andes mountain- Nazca plate and south American

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Constructive plate margin

  • Plates move apart
  • The gap is filled by magma from the mantle
  • Forms shield volcanoes which can form islands

Example: Mid-atlantic ridge- North American plate and Eurasion plate

Conservative plate margin

  • Plates move along side each other
  • They move at different speeds in the same direction
  • Pressure builds up until one plate jerks past the other causing an earthquake 

Example: San Adreas- North American plate and pacific plate.

  • Conservative plate- Fold mountains and earthquakes 
  • Constructive plate- Volcanic island
  • Destructive plate- Fold mountains and earthquakes
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Composite volcanoes

  • Magma chamber- a store of molten rock deep in the earth
  • main vent- The path where the magma rises to the surface
  • lava- magma when on the surface and is called lava flow when flows down a mountain side
  • volcanic bombs- lumps of moltn Rock that solidify as it falls
  • crater - A funnel-shaped hollow at the top of a volcanic cone
  • steam, gas, lava and dust- These are released
  • Falling ash- Small pieces of shattered rock
  • secondary cones- if main vent is blocked and magma is forced to create a new oute

Characteristics 

Composite 

  • Tall cone with narrow base an steep sides
  • Made of alternative layers of ash and lava
  • Irregular eruptions and long dormant periods 
  • Violent explosions 

Shield

  • Cone with wide base and gentle slpes 
  • Made of lava onnly
  • Regular and frequent eruptions 
  • lava pours out with little violence 
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hi

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ember olcanoes kill ppl because   the release poisonous gasees yellow stone created calderas and its gonna kill us all because its a badass wooo ima fail

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j

n

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