Chapter 48 - Fennoscandia: glacial landforms from the Last Glacial Maximum

Abstract

Remarkably few landform assemblages across Fennoscandia can be conclusively tied to the Last Glacial Maximum (LGM) period. In the ice-marginal zone across Denmark, sediment stratigraphic sequences reveal that the ice sheet did not attain a stable position over the defined LGM period, but rather this episode comprises multiple advance events. The maximum extent achieved over this period—long termed the “Main Stationary Line”—is defined and characterised by distinctive till limits and a border between different landscape morphologies, rather than a pronounced end moraine. Extensive outwash plains lie beyond the limit, while dead-ice topography with local push moraines lies in a band inward. The geomorphology of the interior of the ice sheet domain is dominated by the legacy of deglaciation, rather than the maximum period ice sheet. During the LGM period, widespread cold-based ice is thought to have prevailed in the interior, inhibiting sediment mobilisation and subglacial landscape modification. A few discrete and distinct assemblages of glacial lineations are devoid of meltwater landforms, oriented at odds with the deglacial pattern, and consistent with the expected LGM ice divide position, and on this basis interpreted as recording LGM ice flow configuration. Other landscape elements, however, can provide insight into the properties of the LGM ice sheet. The distribution of ribbed moraine, themselves deglacial landforms that dominate the Central and Northern Fennoscandian Shield, has been argued to represent the extent of cold-based ice at the LGM, while raised shorelines (due to isostatic uplift) and mountain summit landscapes have the potential to inform of LGM ice thickness.