Oppland. Beskrivelse til kvartærgeologisk landgeneralkart.

Abstract

The present map of the quaternary deposits of Oppland was prepared on the general principles applied to the preceding map of Oslo and outlined in the accompanying publication, NGU no. 176. As the ice front retired and the remaining ice thinned down, the land ascended. Thus, in the vicinity of Oslo the late glacial marine limit, \"MG\", is situated at 220 m above sea level, while S. of Randsfjorden it is found at 202 m and S. of lake Mjøsa at 190 m. The presence of the marine crustacea Mysis relicta in lake Mjøsa proves that the lake have been invaded by sea water. The clay deposits along the lakes Mjøsa and Randsfjord, however, do not seem to contain marine fossils. The sea pursued the retiring ice front across Romerike and as the ice thickness decreased, hills and ridges appeared. The glacial movement stagnated in the lakes of Randsfjorden, Hurdalssjøen and Mjøsa as well as in the valley of Gåma. Water drillings in Glåma valley have disclosed salt water deriving from marine clay. From this it appears that the valley communicated with the sea.