One topic looked at in GCSE Geography is weathering. This is the natural process which causes the breakdown of rocks and minerals by chemical, biological or physical agents and is not to be confused with erosion. Erosion is the process in which material is moved whereas weathering occurs in situ.
Weathering is the breakdown of rocks, soil and naturally occurring minerals, as well as all the artificial minerals that have been made by human activity, such as bricks and concrete. Weathering is the process that eventually turns mountains into grains of sand on a beach.
Various factors influence the rate of weathering, including:
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When rock has been weakened and broken up by weathering, erosion can then occur. Erosion happens when material is moved to another place by water, gravity, ice or wind
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The three types of weathering are broadly grouped into chemical, biological (also called organic) and physical (also called mechanical)
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This is a great question if you get it in the exam. The clue is in the name - freezing and thawing needs temperatures low enough to freeze and high enough to thaw the ice back to water
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Think of the things freeze-thaw weathering requires: diurnal temperature range, available water and cracks in the rocks. This is so the water can fill the cracks and, as ice forms, expand
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The polar regions are also known as the polar deserts. They are so cold that all the fresh water and a huge amount of the salt water is tied up as ice and never thaws. This means that there is no liquid water to allow freeze-thaw weathering
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Hydration is a chemical process where certain rocks absorb water into their structure. It is a type of chemical weathering
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Biological weathering is sometimes classified as a type of physical weathering, but anything done by living things can be classified as biological weathering
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Iron is one of the major elements found in many types of rock
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In tropical areas, higher levels of rainfall, warmer conditions and better light all lead to a higher rate of vegetation growth which in turn leads to increased weathering. The rainfall and heat also cause weathering themselves
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Exfoliation is the process in which the top layer of rocks is gradually removed via expansion and contraction caused by temperature differences
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