Retreat pattern and dynamics of glaciers and ice sheets: reconstructions based on meltwater features

Abstract: The pattern of ice marginal retreat during the last deglaciation has, thus far, most frequently been reconstructed using absolute dating methods and landform record. In reconstructions using landform record, meltwater system has most often been neglected. This is predominantly a consequence of the smaller scale of meltwater features. However, digital data with high spatial resolution yields the potential source of information that allows for the future mapping of deglacial meltwater system, which in turn can be used in reconstructions of ice marginal retreat pattern at a regional or ice sheet sector scale. Before this potential can be realized, there is a need for rigorous testing of data sources and methodological developments. Available sets of satellite images and digital elevation models (DEMs) covering areas in Scotland, Sweden and Finland were tested in order to evaluate their relevance for mapping meltwater features. This study shows that high-resolution DEMs together with medium-resolution satellite imagery are suitable for the mapping meltwater landforms such as eskers and meltwater channels. To further test the possibility of mapping traces of glacial lakes from satellite imagery, a mapping campaign was launched in the region of central Transbaikalia, Russia. The study comprised a reconstruction of glacial lakes and aimed to compile a glacial geomorphological map of this poorly studied region. The most prominent glacial lake was dammed in the catchment of the River Vitim and covered an area of about 25 000 km2. The landform record indicates that the characteristics and style of glaciation in the area were neither spatially nor temporally uniform. Based on the knowledge from the methodological study and the geomorphological mapping in Transbaikalia, meltwater features have been mapped in central British Columbia and the southern Yukon Territory, Canada. These might provide material for a reconstruction of the ice retreat pattern of the Cordilleran Ice Sheet, which has been the main objective of this PhD project.