The purpose of this study was to map the distribution of till-covered eskers in the inland of Västerbotten County in northern Sweden. The top layers of big eskers along the valleys of Öre River, Ume River and Vindel River were investigated through shallow digging. Findings were investigated through field assessment and soil analysis and many locations with till-covered eskers have been identified in Västerbotten's inland in this survey. The till covering the eskers has probably been transported only short distances and has its origins in glacifluvial material. The pattern is not consistent and there are areas where till does not cover the eskers. This can be explained trough irregular till deposition or that the till has been washed away or alternatively that the upper layer that is interpreted as glacifluvial material actually is till that has only been transported for very short distances. The findings of till-covered eskers in Västerbotten means that the traditional view of the eskers originating from the last deglaciation (Weichsel 3) may need to be reviewed. Where overlaying till has been found on top of eskers it means that the eskers must have originated in an earlier glaciation than the last. Only one layer of till could be discerned on the eskers in the survey, so an explanation could be that the till formed during Weichsel 3 and that the eskers formed earlier by the deglaciation of Weichsel 2, but dating the layers in till-covered eskers is difficult. No transition zone between till-covered to not till-covered eskers was found in this study.

The aim of this study was to map the prevalence of aeolian sand dunes in Västerbotten, northern Sweden to find dunes formed during earlier deglaciation phases, which was then preserved in cold-based conditions during the youngest stadial of the Weichselian glaciation. These preserved dunes were expected to be covered by a layer of till and have a rather faint morphology compared to dunes formed during the Holocene. Consequently, high resolution LIDAR-derived images from the Swedish mapping, cadastral and land registration authority (Lantmäteriet) was used to detect the dunes throughout an area covering most of Västerbotten, above the highest coastline and below the mountain range. The analysis resulted in several new findings of aeolian dunes compared to the findings in the quaternary soil map created by the Geological Survey of Sweden. Despite the fact some of the dunes at the LIDAR-derived image had a strange faint appearance, it was quickly evident during the fieldwork that the aeolian sand was not covered by till on any of the dunes visited. The common view during the last decades has been that cold-based ice will not erode or alter the morphology of the landscape beneath the ice. However, this study suggests that hypothesis may not be entirely correct, and therefore it can be hard to use geomorphological implications to reconstruct past glacial environments. Thus, it can be concluded that even under cold-based conditions, preservation of aeolian sand dunes in Västerbotten is probably not very common.