From relict polygon patterns in South Scandinavia to active ice wedge polygons in Svalbard: A review of former studies

Scandinavian networks of relict ice wedge polygons are revealed by aerial photographs, (a) on the Swedish west coast and in south-western Jutland, Denmark, as vegetation patterns (crop marks) during dry seasons, and (b) in north-eastern Norway, as a pattern of shallow trenches enhanced by vegetation. The most regularly shaped and equally sized polygons occur in south-western Jutland. This is a result of the long period of periglacial frost activity in the environment outside the Weichselian Ice Sheet. The relict polygon areas on the Swedish west coast and in north-eastern Norway are situated in early deglaciated regions. Using dated shoreline records, it may be concluded that these polygons had their last period of activity in the Younger Dryas cold phase. Mean Annual Air Temperature (MAAT) values are discussed based on Péwé's temperature criteria for ice wedge formation. To gain experience of the dynamics of ice wedges, the high-arctic Adventdalen Valley, Svalbard, was chosen as test area. In active wedges in the valley plain, secondary wedges were observed. The climatological significance of the phenomenon is brought forward and discussed in view of the present climatic situation. The secondary wedges are interpreted as indicators of climatic cooling.

Keywords:

• aerial photographs
• climatic cooling
• crop mark
• ice wedge
• relict polygon pattern
• paleoenvironment