A phenomenon found in cirques and in the steps of glacial troughs, where the middle section(s) of the feature are lower than the mouth. One suggestion is that the overdeepened section is the zone of maximum ice thickness, another that overdeepening coincides with less resistant rocks. Evans (1999) Annals Glaciol. 28 ascribes overdeepening to rotational flow, while Hooke (1991) GSA Bull. 103, 8 describes a positive feedback process, as overdeepening causes crevassing at the surface, resulting in erosional forces that accentuate that overdeepening.
Subjects: Earth Sciences and Geography.