Cirques at Low Altitudes Need Not Necessarily Have Been Cut by Small Glaciers

ABSTRACT

Cirques at low altitudes in Sweden are, from a climatological point of view, not likely to be a result of cirque glaciation but rather of subglacial erosion under a wet based inland ice-sheet. In this paper a comparison is made between cirque forms and forms excavated under the presently existing Storglaciären in northern Sweden.

Cirques have been observed in Sweden at low altitudes on locations where todays climate is continental (Agrell 1977, Rapp 1984, Rudberg 1984, Vilborg 1984). It is difficult to visualize the colder and more maritime climate needed to create wet-based cirque glaciers. The glaciation level is approximately 1500–2000 metres higher than the highest summits in these areas. A lowering of the glaciation level of this amount corresponds to a more than 10° C lowering of the annual temperature. As the interior of northern Sweden today is close to the limit of discontinuous permafrost, such drop in temperature would most certainly lead to continuous permafrost in the entire area. Under such climatic circumstances small cirque glaciers do not erode their bottoms. Thus, either many of these cirques are incorrectly interpreted or there is something wrong with the definition of cirques.