The Baltic Sea Ice Stream

This is an interesting map from the article, showing the "footprint" of the Baltic Sea Ice Stream within the Fennoscandian Ice Sheet.  This is a composite map, showing what might have happened during several glacial episodes.  The ice stream is topographically constrained on its western flank by the Caledonian Mountains -- but to the east there is no obvious constraint apart from the fact that ice was forced to flow in the most efficient way possible, southwards along the basin, with more sluggish ice to the east -- probably with a shearing zone along the junction.  

The amount of debris excavated and dumped is impressive -- in excess of 30,000 km3.

There are obvious similarities with the Irish Sea Ice Stream with which we are all familiar -- but the main difference was that the BSIS was land-terminating and the ISIS was marine terminating.  I'll explore that issue in another post........

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Adrian Hall & Mikis van Boeckel (2020): Origin of the Baltic Sea basin by Pleistocene glacial erosion, GFF, DOI: 10.1080/11035897.2020.1781246

To link to this article: https://doi.org/10.1080/11035897.2020.1781246

ABSTRACT

The present marine Baltic Sea basin (BSB) occupies an eroded Proterozoic intra-cratonic basin on the Fennoscandian shield. Competing models propose a Neogene fluvial origin, with later modification by glacial erosion, or a much younger development, with overdeepening beneath the Fennoscandian Ice Sheet (FIS). We test these alternatives using a first order source to sink sediment budget for the catchment of the BSB. Best estimates derived from geomorphic and cosmogenic nuclide evidence suggest depths of erosion over the last 1 Ma of 20 m in basement and 40 m in sedimentary rocks that surround the BSB. As the BSB has been overdeepened below a regional base level provided by the shallow Darss Sill at the boundary with the Kattegat, erosion of the BSB may be interpreted as glacial in origin, without a fluvial component. The estimated total volume of source area erosion is 30,628 km³ of which 87% is derived from the present BSB. Sediment volumes in the sink area within the limits of maximum Pleistocene glaciation are estimated at a minimum of 37,629 km³, after correction for local erosion, porosity, and carbonate losses. Marine Isotope Stage 12 and younger sediments account for 87% of the total Pleistocene sediment volume in the sink in Poland. Although significant uncertainties remain, the sediment budget is consistent with erosion of the BSB entirely by the FIS, mainly when the ice sheet reached its maximum extent and thickness during the Middle and Late Pleistocene glaciations.