Geography the Restless Earth

Unit 1

The Restless Earth

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Structure of the Earth

The Earth's surface is made of huge floating plates that are constantly moving.

The Earth's is separated into tectonic plates

1. At the centre of the Earth is a ball of solid iron and nickel called the core.

2. Around the core is the mantle, which is semi-molten rock that moves very slowly.

3. The outer layer of Earth is called the crust. Its very thin (about 20km)

4. The crust is divided into lots of slabs called tectonic plate (they float on the mantle). Plates are made of two types of crust - continental and oceanic:

  • Continental crust is thicker and less dense
  •  Oceanic crust is thinner and more dense

5. The plates are moving are moving because the rock in the mantle underneath is moving them.

6. The place where plates meet is called boundaries or plate margins

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Structure of the Earth

(http://fionamariecarter.files.wordpress.com/2011/04/image004.jpg?w=557&h=482)

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Plate Margins - DESTRUCTIVE

Destructive plate margins are two tectonic plates, oceanic and continental smash together, e.g. The East coast of Japan 

  • When the Continental plate meets the Oceanic plate, the Oceanic plate is  ALWAYS forced down into the mantle where it is destroyed. Due to this action Volcanoes and Ocean trenches are created.
  • However if two Continental plates meet, none of them are destryed as they create a fold mountains, e.g. the Alpes 
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Plate Margins - DESTRUCTIVE

(http://cgz.e2bn.net/e2bn/leas/c99/schools/cgz/communities/Geography/AS%20Geography/AS%20Revision/Earth%20Systems%20Revision/Types%20of%20Plate%20Boundaries-tvl-media-2-quizX5Fid-z20051228202037259X2DovalX2D5137X2D93-u-20051228202037259X2DovalX2D5137X2D93-z-f.jpeg)

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Plate Margins - CONSTRUCTIVE

A constructive plate margin is when two plates either Constructive or Oceanic are moving away from each other, e.g. the mid-Atlantic ridge. magma rises from the mantle and creates new crust.

(http://www.revisionworld.co.uk/files/seafloor.jpg)

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Plate Margins - CONSERVATIVE

Conservative margin is when two plates are moving side by side in thesame direction or past each other, it does not create or destroy crust, e.g. west coast of USA.

(http://cgz.e2bn.net/e2bn/leas/c99/schools/cgz/communities/Geography/AS%20Geography/AS%20Revision/Earth%20Systems%20Revision/Types%20of%20Plate%20Boundaries-tvl-media-4-quizX5Fid-z20051228202347746X2DarchwayX2D9805X2D3-u-20051228202347746X2DarchwayX2D9805X2D3-z-f.jpeg)

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Fold Mountains

Fold Mountains are Formed when Plates Collide at Destructive Margins

1. When tectonic plates collide, layers of sedimentary rock rises up creating a fold mountain.

2. Therefore Fold mountains are found at destructive plate margins

3. you can also get Fold Mountains where the Continental and the Oceanic plates collide.

4. You can also get fold mountains where the two continental plates collide.

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Fold Mountains

(http://cgz.e2bn.net/e2bn/leas/c99/schools/cgz/communities/Geography/AS%20Geography/AS%20Revision/Earth%20Systems%20Revision/Types%20of%20Plate%20Boundaries-tvl-media-3-quizX5Fid-z20051228202104009X2DhighgateX2D3586X2D5-u-20051228202104009X2DhighgateX2D3586X2D5-z-f.jpeg)

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Fold Mountain Case study

The Alps is a Fold Mountain Range About the Alps? 

 It was formed over 30million years ago, which was caused by the collision of the African and European plates. 

Central locations are: Austria, France, Germany, Italy, Liechtenstein, Slovenia and Switzerland. The tallest peak was 4810 metres, at the Italian-French border, Mont Blac.

The Advantages of the Alps are:

  • FARMING- Goats which are farmed at the mountains provide milk, cheese and meat.
  • TOURISM- 100million tourist visit the Alps every year, which is a huge part of the economy.
  • HYDRO-ELECTRIC POWER (HEP)- The electricity that is produced is used to power the local homes, businesses and town further away.
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Fold Mountain Case study

(http://i.telegraph.co.uk/multimedia/archive/01417/PD29283864_Gambert_1417343c.jpg)

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Volcanoes

Volcanoes can be found at the Destructive and Constructive Plate Margins.

At the destructive plate margins the Continental plate stays on top whilst the Oceanic is pushed down as it is less dense, and it is melted and destroyed. That is where the pool of magma is formed, the magma escapes through the vent onto the crust and is now called lava forming a volcano.

However at the Constructive plate margin magma rises up through the crack that was made by the plates moving apart, forming a volcano.

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Composite Volcanoes

Composite volcanoes usually have thick lava that flows slowly, but it hardens quickly. The features are: Steep sides, Layers of ash, Layers of lava and a vent.

(http://www.clipart.dk.co.uk/DKImages/sci_earth/image_sci_earth016.jpg)

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Shield volcanoes

The lava is runny, it flows quickly and spreads over a wide area, creating a low and flat volcano. Some of the features are: Runny lava, Low and Flat and Layers of lava with out ash.

(http://www.clipart.dk.co.uk/DKImages/sci_earth/image_sci_earth014.jpg)

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Dome volcanoes

It has a thick lava, which runs slowly and hardens quickly. Some of the features are: Thick lava, Steep sided and Layers of lava without ash.

(http://www.clipart.dk.co.uk/DKImages/sci_earth/image_sci_earth015.jpg)

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