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Weathering and Rocks - Coggle Diagram

- - - - Van't Hoff's Law is the rate of chemical weathering increases 2-3 times for every increase in temperature of 10 degrees
      - Efficiency of freeze thaw, salt crystallization and insolation are affected by, temperature changes, frequency of cycles and diurnal/seasonal changes
  - - - Eg. limestone consists of calcium carbonate so susceptible to carbonation solution
      - Eg. granite is prone to hydrolysis because of the feldspar
  - - - Rocks made of weaker minerals will weather faster, limestone
  - - - Vegetation weathers rocks through the secretion of organic acids, chemical and the growth of roots, physically weathers soil
      - Depth of soil can protect rocks from vegetation or can support vegetation to help it to weather rocks
- - - - This causes pressure on the rock and the outward force exceeds the resistance of the rock
        
        This causes it to crack and forms faults
  - - - This creates pressure on the joints, forcing cracks
      - The sodium salphate and sodium carbonate expand by about 300%
    - - When the temperature rises the crystals expand causing pressure on the rock
  - - - Daytime temperatures are 40 degrees, night time temperatures are little above freezing so rocks heat up during day and contract at night
        
        This causes exfoliation of the outer layers of rock
  - - - This leads to underlying rocks expanding and fracturing parallel to the surface
        
        Removal of large weights like glaciers has the same effect
        
        The removal of overlying rocks causes cracks or joints to form at right angles to the unloading surface
        
        These are lines of weakness
        
        If overlying pressure is released, horizontal pseudo-bedding planes will be formed
        
        If horizontal pressure is released eg. cliff face, than vertical joints will form
- - - - Rainfall combines with dissolved carbon dioxide or organic acid to form weak carbonic acid
      - Calcium carbonate reacts with an acid water to form calcium bicarbonate
  - - - Feldspar reacts with acid water to form Kaolin, silicic acid and potassium hydroxyl
        
        The acid and Hydroxyl are removed leaving kaolin, other minerals like quartz, mica remain in the kaolin
  - - - Eg. anhydrite is changed to gypsum
        
        When that happens it expands by about 0.5%
        
        Volume can also increase of up to 1600% by shales and mudstones when clay minerals absorb water
      - Mechanical stresses occur also