earth science (weathering)

    Cards (16)

    • Frost wedging, when water gets inside the joints, alternate freezing and thawing episodes pry the rock apart
    • Salt crystal growth, force exerted by salt crystal that formed as water evaporates from pore spaces or cracks in rocks can cause the rock to fall apart
    • Abrasion, wearing away of rocks by constant collision of loose particles
    • Biological activity, plants and animals (including humans) as agents of mechanical weathering
    • Dissolution, dissociation of molecules into ions; common example includes dissolution of calcite and salt
    • Oxidation, reaction between minerals and oxygen dissolved in water
    • Hydrolysis, change in the composition of minerals when they react with water
    • Climate, areas that are cold and dry tend to have slow rates of chemical weathering and weathering is mostly physical; chemical weathering is most active in areas with high temperature and rainfall
    • Rock type, the minerals that constitute rocks have different susceptibilities to
      weathering
    • The susceptibility of minerals (from high to low) roughly follows the
      inverse of the order of crystallization of minerals in the Bowen’s reaction series
    • Olivine which crystallizes first is the least resistant whereas; quartz which crystallizes
      last is the most resistant.
    • Rock structure, rate of weathering is affected by the presence of joints, folds, faults,
      bedding planes through which agents of weathering enter a rock mass
    • Highly jointed/fractured rocks disintegrate faster than a solid mass of rock of the same
      dimension
    • Topography, physical weathering occurs more quickly on a steep slope than on a
      gentle one
    • On a gentle slope, water may stay longer in contact with the rocks, hence chemical weathering is enhanced.
    • Time, length of exposure to agents of weather determines the degree of weathering
      of a rock