The significance of rock glaciers in the glacial‐periglacial landscape continuum

Abstract

AbstractRock glaciers are distinct landforms whose wide distribution, occurrence, and significance often go unrecognised. They are deposits of poorly sorted, angular, blocky to tabular debris which are held together by an ice core or a matrix of ice‐cemented fine clastics. Rock glaciers have formed in glaciated and non‐glaciated areas. Many researchers have suggested that the absence of an ice core or the lack of movement indicates relict or fossil status. Active and inactive states can be viewed as the end members of a movement continuum. Movement rates, derived from world‐wide locations as reported in the literature, range from less than 1 cmyr−1 to greater than 130cmyr−1. Unfortunately, lack of observed movement has been equated incorrectly with an inactive status.Rock glacier movement must be considered from a rheological point of view. Movement is controlled by the transformation of potential energy to kinetic energy as the system attempts to reach thermal equilibrium or stability. Whereas a glacier can completely disappear or redevelop, reactivation of a rock glacier requires only the re‐establishment of the conditions responsible for development and maintenance of interstitial ice. Although it might not be possible to re‐establish an ice core, interstitial areas can definitely be recharged with ice and thus facilitate movement. The concept of active versus inactive should be abandoned in favor of the view that a spatial and temporal continuum of form and movement exists.