Drumlins and flutings in Finland: their relationships to ice movement and to each other

Abstract

Drumlin fields are numerous and widespread in Finland and flutings are common in the same areas. The impressive Kuusamo drumlin field in northeastern Finland covers older drumlins whose features are evident from beneath the younger till bed. In many cases the orientations of the overlying younger streamlined forms deviate from the orientations of the forms lying beneath them. The majority of drumlins and flutings form fan-like patterns reflecting the configuration of active ice lobes. The orientations of the smallest fluting ridges vary in places more than those of the drumlins in the same area. It is suggested that small flutings tend to denote the youngest direction of ice movement. Bending of some drumlins and flutings indicates a curvilinear motion of the ice, and some drumlins with forks pointing in a slightly different direction were perhaps caused by a slight shift in ice movement. Large groove-type flutings in the bedrock took a great deal of time to develop and do not therefore always show the direction of ice movement during deglaciation.