Frost Weathering

The process of frost weathering of bedrock occurs in areas where temperatures are below-zero, be it on a diurnal, seasonal or multi-annual basis.

The first application that included frost weathering in LAPSUS, was Temme and Veldkamp’s study in South Africa.

Case Studies: » South Africa

Technical Information

A simple implementation was designed that takes into account that weathering occurs perpendicular to the surface, that a certain below-zero maximum air temperature is required, that no extra frost-weathering occurs when temperatures are below a certain minimum and that soil buffers temperature changes (Bloom, 1998):

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Where ef is the volume of frost weathering (m),  F0 is the maximum frost weathering on a flat surface given lithology (m t-1), T is the Mean Annual Average Temperature (MAAT) (°C), Tmax is the maximum MAAT (°C), Tmin is the minimum MAAT (°C), a is the buffering parameter for soil thickness (°C m-1), and cos α is the cosine of slope [-].This implementation assumes a linear decrease of frost weathering with increasing soil thickness. In reality, amplitudes of temperature change decrease exponentially with increasing soil thickness (e.g.Minasny and McBratney, 1999) and frost weathering rates likely would too. Also, differences in lithology are not yet taken into account.

References

  • Bloom, A.L., 1998. Geomorphology. Prentice Hall, Upper Saddle River, 482 pp.
  • Minasny, B. and McBratney, A.B., 1999. A rudimentary mechanistic model for soil production and landscape development. Geoderma, 90(1-2): 3-21.