Drumlins of Estonia

Abstract

Drumlins, megaflutings and other subglacial streamlined forms, highly variable in shape and size, are widely distributed in Estonia as well as on the bottom of the Gulf of Finland, which was also affected by continental ice. Their total number amounts to 1000. The main drumlin fields are most common in Central Estonia on lateral slopes of bedrock uplands and/or in depressions between them, and they serve as a transitional landscape type between predominantly erosional (in northern Estonia) and depositional zones (in southern Estonia) of the Scandinavian ice sheet. Nevertheless, the local details of bedrock topography and glacial and deglacial history have led to some deviations (e.g. the unique Saadjärv field of big drumlins and megaflutings is situated in a “glacier shadow”, on the lee side of a bedrock upland). Being of varied composition and age, drumlins and related streamlined forms represent complex interactions between erosional, transporting and depositional processes, although the dynamics of their formation are still somewhat enigmatic. It seems that in Estonia drumlins were formed both during ice advances and retreats. In some cases there are moraine hillocks, kames and eskers and other ice disintegration features superimposed on drumlins.