Kvartære avleiringer i Østfold

Abstract

This paper is a contribution to the quaternary geolgoy of the south-eastern part of Norway. The district lies between the Oslo Fjord and the Swedish frontier. The map, fig. 1 shows the direction of the movement of ice during the last phase of the glaciation. It has moved in a south south-westerly direction towards the basin of the Oslo Fjord. Where crossing striae occur the younger of these have a more southerly to south-easterly direction. They are more affected than the older by the forms of relief. Several ridges of terminal moraines occur in this district, of which the Ra ridge is best known. This ridge passes the frontier from Dalslannd in Sweden and stretches in a north-westerly direction through Østfold to Moss at the Oslo Fjord. Running parallel with the Ra here are several other moraine ridges. one of these lies outside the Ra, the others inside it. These moraines were deposited from the ice border into the sea, and the gravel in them is therefore bedded.