The presence of permafrost in Poland north of the line indicating the maximum ice extent of the Vistulian (Weichselian) glaciation after retreat of the land-ice cap has been a subject of debate for a long time. Investigations in an area at the line of the maximum ice extent of the Pomeranian phase prove that permafrost existed, indeed, after the ice retreat. This conclusion is drawn on the basis of morphological data (the presence of oriented kettle holes), sedimentological data (the nature of the infilling of the kettle holes) and pedological data (permafrost-affected horizons in soil profiles). It appears that the permafrost mostly developed in the ice-free zone that appeared after the retreat of the land-ice cap, but it is likely that some relict permafrost that had originated earlier in front of advancing ice was also still present. The landscape of northern Poland owes its relief partly to the Late Glacial permafrost.
