Past and Present Permafrost Distribution in the Turtmanntal, Wallis, Swiss Alps

Abstract

The permafrost distribution in an alpine valley in the Swiss Alps has been mapped using topoclimatic rules of thumb and a geomorphological interpretation of aerial photographs. Most attention has been given to active rock glaciers, which are reliable features to predict permafrost occurrence. Seismic measurements are used to check the permafrost distribution obtained using the mapping method. These measurements give approximately the same permafrost limits as achieved by rules of thumb. They also provide an image of the complexity of permafrost distribution in the Alpine Belt of discontinuous permafrost. Attention has been paid to the relationship between permafrost and glaciers. Most of the small glaciers are in the belt of discontinuous permafrost and they probably were during the Little Ice Age Maximum. A method for reconstruction of past permafrost distribution using fossil rock glaciers and glacial deposits is presented along with a test case.