Fennoscandia: Glacial landforms during initial deglaciation (18.9–14.6 ka)

During the initial period of deglaciation following the Last Glacial Maximum (LGM), the Fennoscandian ice sheet margin withdrew from its marine sectors towards the terrestrial core of the ice sheet domain. The landform record of this period of retreat along the western and northern coastal margins is rather limited; ice flow appears to become increasingly constrained by the high-relief topography. Conversely, in the lower-lying southern sectors the landform record of initial deglaciation is rich and varied. Here, the patterns of ice sheet retreat have long been known, defined by pronounced arcuate moraine ridges, superimposition of deglacial landforms upon earlier, differently oriented LGM assemblages, and by regional-scale, laterally-continuous moraines and esker-delta/sandur complexes that bound the radial flow of lineations and meltwater. In recent years, high-resolution LiDAR-based terrain data have stimulated renewed investigation of these landscapes. New landform types (murtoos) and landform associations (hummocky meltwater corridors) have been recognised and formerly known landscapes revisited, together driving reassessments and new hypothesis-building regarding subglacial landforming processes and their coupling to thermal regime and the meltwater system. The Baltic Sea domain remains poorly known; high-resolution seafloor data would shed light on the function of the Baltic ice stream(s) during deglaciation, and the pattern and style of subaqueous grounding line retreat in comparison to the terrestrial sectors of the southern ice sheet margin.