Some Observations on Superimposition of Ice on the Devon Island Ice Cap, N.W.T. Canada

Abstract

The zone of superimposed ice formation is defined and divided into two sub-zones, one of continuous and the other of discontinuous superimposed ice formation. Layering in superimposed ice is discussed and it is evident that an annual increment may consist of a series of layers which can occur in various orders according to the melt and freezing conditions obtaining. A laboratory analysis of superimposed ice did not reveal any valid method for division into annual layers. A crystal analysis indicates there is an increase in the mean crystal size and the standard deviation from this mean with decreasing altitude between the firn edge and the equilibrium line. Below the latter the pattern is reversed. This phenomenon is used to determine a long period equilibrium line.