Origin of rock glaciers: Observations from Mellemfjord, Disko Island, Central West Greenland

Surface and interior characteristics of a tongue-shaped rock glacier at Mellemfjord on Disko Island are described. A long natural section shows the existence of a solid ice core. The implications for the origin of ice within the rock glacier and its surface debris layer are discussed and, from this, the rock glacier age is estimated at about 550 years; that is, it was probably initiated during the initial period of the Little Ice Age. It is suggested that the climatic control on ice-cored rock glaciers in particular is more pronounced than traditionally assumed. It is suggested that although the geomorphological feature described displays many characteristics of a normal glacier, it should be classified as a true rock glacier.