Rocks and weathering

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  • Rocks and weathering
    • Types of Rocks
      • Igneous
        • Formed through the cooling and solidification of magma.
        • Has crystals, but no fossils.
        • No layers
      • Metamorphic
        • A result of transformation of pre-existing rock. The original rock, sedimentary, is subjected to very high heat and pressure, which causes change.
        • Formed in layers. more compressed than sedimentary.
        • Has fossils and crystals.
      • Sedimentary
        • Made up of river deposits. when they build up they are called sediments, the water is squeezed out and they stick together.
        • Contain large grains, and large layers.
        • contains lots of fossils.
    • Types of Weathering
      • Physical Weathering
        • Freeze thaw
          • Water is held within a crack.
          • If the water freezes it will expand, putting pressure on the rock.
          • If the temperature rises above 0 then the ice will melt
          • If this happens repeteadly then the rock will weaken, eventually shatter.
        • Onion Skining
          • When a rock gets hot it expands a little. And when it cools it contracts.
          • It this process happens lots then cracks form and pieces of rocks break away.
          • This happens a lot in desserts.
      • Biological Weathering
        • Animals and plants wear away rocks.
        • Weeds, rabbit wholes and trees all can create cracks which eventually lead to the rock falling away.
        • Humans also cause biological weathering, just by walking.
      • Chemical Weathering
        • Rain water is slightly acidic because of all the carbon dioxide dissolves in it.
        • Limestone and chalk is heavily effected by this type of weathering because calcium carbonate is easily dissolved by this acidic substance.
        • Humans also contribute by all the pollutions we produce causes acid rain aswel.
    • Limestone Pavement Formation
      • Limestone Pavements are formed when the limestone is exposed to weathering.
      • Rain is slightly acidic an dissolved calcium carbonate (limestone). The weaker parts of the rock erode the quickest, leaving shallow pathways.
      • Over time the pathways deepen as the water tries to go downwards.
      • You get left with clints and Grykes which are limestone paveing
    • Case Study-Limestone in the Yorkshire Dales
      • Location
        • The Yorkshire Dales are situated on the continent of Europe, in the northern hemisphere, they are on an island called Britain, and placed in the North above Lincolnshire, but bellow the Lake District.
      • Use of the Landscape
        • Tourism
          • Tourist visit the area to go walking, caving, cycling, camping, climbing and for educational visits.
          • Over 8 million visitors provide employment and an important boost on the local economy.
        • Quarrying
          • It is very important for the local economy.
          • Limestone quarrying in used for lots of things including cement and fertiliser
      • Conflicts from the way the land is used
        • Honey-pot sites such as Malham become congested with cars and tourists, causing conflict with the local people.
        • Ramblers can cause conflict with the farmers by dropping litter and not shutting gates
        • Some tourists buy second homes which raises the house prices up, so the local people cant buy them.
        • Environmental damage to the paths, by all the tourists walking on them.
        • The quarry owners cause conflict with the environmentalists because they may want them to stop digging up the land and putting toxic fumes into the air.

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