The Fennoscandian Ice Sheet during the Younger Dryas Stadial

The Younger Dryas (YD) moraines have been mapped almost continuously around the Fennoscandian ice sheet. Segments of the moraine have individual names, best known are the Salpausselkä in Finland, the Middle Swedish moraines in Sweden and the Ra and the Herdla-Halsnøy moraines in Norway. The outline of the ice margin was very different around the ice sheet, with narrow fjord glaciers in western Norway and smoother margins and wide lobes in the lowlands of Sweden and Finland. The form and composition of the ice-marginal deposits also vary from narrow till ridges to large deltas and sandurs. Along many stretches there are two or more parallel ice-marginal deposits, notably in Finland and Sweden, whereas there is often only one ridge in western Norway. Most of the moraines are confidently dated to the YD, but with some variation in precise timing; the Herdla-Halsnøy moraines were formed at the very end of the YD, the outermost Salpausselkä and Middle Swedish moraines were formed earlier during the YD. In a few places it is unclear if all parallel ridges are of YD age.