1 Matching Annotations
  1. May 2017
    1. frost heave
      Before the understanding of frost heave, there was a widely held belief that rocks and stones could grow and multiply. Stones were believe to grow from small pebbles. These stones then rose to the surface of the ground. Another belief was that stones were the offspring of “mother-stones” or “breeding-stones.” Today, it is known that this motion of stones moving upwards toward the surface of the ground is due to frost heave. Frost heave occurs when water in soil or rock freezes and thaws in a cyclic process. This causes an upward movement of the surface of the ground due to the freezing of water underneath. Geologist Stephen Taber from the University of South Carolina proved through extensive research that “it was not expansion, but rather the formation of ice lenses by segregation of water from the soil as the ground freezes that is the principal cause of frost heave.” He also showed that liquids other than water can also cause frost heave. The direction of heave is governed by the growth of ice lenses. Ice lenses form perpendicular to the direction of heat flow, so it is not always the case that frost heave occurs in the path of least resistance (Manz, 2011). 
      

      References

      Manz, L. (2011). Frost Heave. Geo News, 18-23.