From ice-dammed lake to aeolian dunes in the Store Mosse area, SW Sweden

Wind is a significant geomorphological agent in formerly glaciated areas and aeolian deposits surround and stretch across the Store Mosse (Great Bog) bog complex in southwestern Sweden. Both peat and aeolian sand are underlain by lacustrine sediment and the deposits record the area's transition from an initially ice-dammed lake to Ancient Lake Bolmen, which gradually drained, exposing sediments to wind erosion and allowing peat to start forming in basins.

Here, we present 25 luminescence ages from lacustrine, fluvial and aeolian deposits that range from the time of deglaciation (∼14.5 ka) to the late Holocene (∼3 ka). Most of the waterlain sediments are dated to 11.5–11 ka while the bulk of the dunes formed 10–6.5 ka ago, possibly during two phases in the early and early-middle Holocene, respectively. The parabolic shape of some dunes indicates aeolian deposition or reworking in a partially vegetated environment, and contemporary dune and peat formation suggest a mosaic landscape in the early Holocene. Younger sand drift events and re-activation of some dunes are corroborated by windblown dust events in mid-late Holocene and are likely related to regional storm periods. The results add to the growing understanding of aeolian activity in formerly glaciated landscapes and illustrate a complex interaction of lacustrine, fluvial and aeolian processes.

The optically stimulated luminescence (OSL) dating was done on 180–250 μm quartz grains, which showed relatively dim luminescence signals dominated by a fast component. Several ages have relatively low precision which could be due to sediment mixing, either by bioturbation or by sampling across a significant layer thickness with an auger.