Weichselian in central South Norway: the Gudbrandsdal Interstadial and the following glaciation.

Present knowledge of sub-till sediments found in the valleys in the Mid-Gudbrandsdal area and the stratigraphy of the overlying basal tills is summarized. The existence of widespread waterlain sediments which are thought to have been depostied in a cold ice-free period of Middle/Early Weichselilan age, the Gudbradnsdal Interstadial, gives evidence of surprisingly modest ice erosion during the last ice age, even in valleys close to the highest mountains. Judging by the nearly total evacuation of older deposits from the tributaries, the ice-free period seems to have lasted for a long time, with very strong slope processes. Huge quantities of proglacial sandur sediments accumulated in the main valleys indicate that the last inland ice sheet grew slowly. By comprehensive analyses the authors have succeeded in correlating the overlying tills with four regional glacial phases of the last ice age reconstructed mainly through analyses of striae. It is found that the conservation of the sediments, as well as the distribution of different tills, was dependent on the relative location of the ice divide.