During retreat of the Fennoscandian ice sheet, a large ice-dammed lake formed along its south-eastern margin. The ice damming this Baltic Ice Lake (BIL) was breached at the northern tip of Mt Billingen, resulting in a catastrophic drainage of _9400 km3 of meltwater and an associated lowering of the BIL by _25 m. This event occurred at _11500 calibrated 14C yr, determined using bio-, litho, and chrono-stratigraphic data from numerous lake and bog cores in the immediate vicinity of Mt Billingen (e.g. Björck, 1995) and the varve chronology from the Baltic Sea tied to the GRIP _18O record (Andrén et al., 2002). The dramatic fall in the level of the BIL is recorded by raised shorelines, isolation of lake basins, and changes in the characteristics of marine sediments (Bodén et al., 1997; Lambeck, 1999). We collected material for a pilot study from (1) scoured bedrock directly in the path of the meltwater outflow, (2) large (> 2m x 2m x 2m) sandstone boulders derived from the northern tip of Mt Billingen and transported by the flood, (3) bedrock from a meltwater-scoured area further down-current (called Klyftamon), and (4) cobbles from the surface of thick floodwater deposits downstream of the scoured Klyftamon bedrock surface. The results of 10Be analysis of these samples are internally consistent between the sampling locations, and we compare these to the available 14C data in order to assess the validity of the site as a potential calibration site for cosmogenic nuclide methods.
Andrén, T., Lindeberg, G. and Andrén, E., 2002. Evidence of the final drainage of the Baltic Ice Lake and the brackish phase of the Yoldia Sea in glacial varves from the Baltic Sea. Boreas, 31: 226-238.
Björck, S., 1995. A review of the history of the Baltic Sea, 13.0-8.0 ka BP. Quaternary International, 27: 19-40.
Bodén, P., Fairbanks, R.G., Wright, J.D. and Burckle, L.H., 1997. High-resolution isotope records from southwest Sweden: The drainage of the Baltic Ice Lake and Younger Dryas ice margin oscillations. Paleoceanography, 12(1): 39-49.
Lambeck, K., 1999. Shoreline displacements in southern-central Sweden and the evolution of the Baltic Sea since the last maximum glaciation. Journal of the Geological Society, London, 156: 465-486.