Glacial flow indicators in air photographs
Visual interpretation of air photographs can yield information on the depths of the Quaternary deposits and the genetic types which they represent, the directions of glacial flow, material transport and the glacial dynamics. Major bedrock landforms can develop streamlined forms reminiscent of polished rock surfaces, if the glacial flow continued for a long period and/or occurred repeatedly with the same orientation, as happened in the case of the Fennoscandian ice sheet in the basin formed by the Gulf of Bothnia and the Baltic Sea proper. Landforms composed of glacial deposits, and particularly moraine landforms, are among the most important indicators of ice movement detectable in air photographs. Fluted moraine surfaces have proved to be significant indicators of glacial flow, at least in the area close to the centre of glaciation in Fennoscandia. The mode of creation of a glaciofluvial formation will also depend on the properties of the glacier, including its dynamics.