Some observations on the growth and deformation of epigenetic, syngenetic and anti‐syngenetic ice wedges

Ice wedges are normally classified into two main types: epigenetic and syngenetic. Epigenetic wedges grow wider rather than higher or deeper. Syngenetic wedges grow both wider and higher more or less simultaneously with the deposition of material at the growth site. Field studies show that there is a third type, an anti‐syngenetic wedge, which grows downward on receding slopes in a direction normal to the slope. The downward growth rate is a function of the rate of ice‐veinlet growth and slope recession. The downward growth of an anti‐syngenetic wedge at a site with a net removal of material is thus opposite to that of the upward growth of a syngenetic wedge at a site with a net addition of material. The deformation of epigenetic, syngenetic and anti‐syngenetic wedges by shear and creep may complicate attempts at age‐dating the wedges by ice petrofabrics, stable isotopes and other methods.