A rock glacier and moraine–ridge complex, Lyngen Peninsula, north Norway

A low-altitude rock glacier associated with two small come glaciers on the Lyngen Peninsula is described on the basis of aerial-photographic interpretation. It is argued that a rock glacier originated when rock-fall debris from the corrie headwall covered the gently-sloping lower part of the two coalesced glaciers during the 19th century. Continued glacier wastage resulted in the separation of the glacier from the rock glacier. The rock glacier has experienced markedly differential flow; one part, by 1954, had advanced as a narrow lobe beyond the Neoglacial moraine ridges into the valley bottom. Some theoretical implications of rock glaciers cored by glacier ice are considered: the relationship of debris accumulation to ice mass balance on such a thin corrie glacier appears to be critical, and if the ablation is effectively, reduced by a debris cover, then a rock glacier can form. It is proposed that such a rock glacier's ice core can be replenished by a much-reduced ice mass gain to the upper corrie glacier and that a healthy rock glacier can exist where debris-free glaciers in the vicinity are retreating. In the present case, however, the separation of the rock glacier from its ice source has resulted in its ultimate stagnation.