HR: 1340h
AN: PP13A-1473    [Abstracts]
TI: A Digital 3D-Reconstruction of the Younger Dryas Baltic Ice Lake
AU: * Jakobsson, M
EM: martin.jakobsson@geo.su.se
AF: Dept. of Geology and Geochemistry, Stockholm University, Svante Arrhenius vag 8c, Stockholm, 106 91 Sweden
AU: Alm, G
EM: alm@natgeo.su.se
AF: Dept. of Physical Geography and Quaternary Geology, Stockholm University, Svante Arrhenius vag 8c, Stockholm, 106 91 Sweden
AU: Bjorck, S
EM: svante.bjorck@geol.lu.se
AF: Dept. of Geology and Quaternary Sciences, Lund University, S”lvegatan 12, Lund, 22362 Lund Sweden
AU: Lindeberg, G
EM: greger.lindeberg@sgu.se
AF: Swedish Geological Survey, Uppsala, Uppsala, 751 28 Sweden
AU: Svensson, N
PP13A-1473 AF: Riksantikvarieambetet UV Syd, Akergrand 8, Lund, 226 60 Sweden
AB: A digital 3D-reconstruction of the final stage of the ice dammed Baltic Ice Lake (BIL), dated to the very end of the Younger Dryas cold period (ca. 11 600 cal. yr BP) has been compiled using a combined bathymetric-topographic Digital Terrain Model (DTM), Scandinavian ice sheet limits, Baltic Sea Holocene bottom sediment thickness information, and a paleoshoreline database maintained at the Lund University. The combined bathymetric-topographic Digital Terrain Model (DTM) model used to reconstruct the ice dammed lake was compiled specifically for this study from publicly available data sets. The final DTM is in the form of a digital grid on Lamberts Equal Area projection with a resolution of 500 x 500 m, which permits a much more detailed reconstruction of the BIL than previously made. The lake was constructed through a series of experiments where mathematical algorithms were applied to fit the paleolake's surface through the shoreline database. The accumulated Holocene bottom sediments in the Baltic Sea were subsequently subtracted from the present bathymetry in our reconstruction. This allows us to estimate the Baltic Ice Lake's paleobathymetry, area, volume, and hypsometry, which will comprise key input data to lake/climate modeling exercises following this study. The Scandinavian ice sheet margin eventually retreated north of Mount Billingen, which was the high point in terrain of Southern central Sweden bordering to lower terrain further to the North. As a consequence, the BIL was catastrophically drained through this area, resulting in a 25 m drop of the lake level. With our digital BIL model we estimate that approximately 7, 800 km3 of water drained during this event and that the ice dammed lake area was reduced with ca 18 percent. The digital BIL reconstruction is analyzed using 3D-visualization techniques that provide new detailed information on the paleogeography in the area, both before and after the lake drainage, with implications for interpretations of geological records concerning the post-glacial environmental development of southern Scandinavia.
DE: 0726 Ice sheets
DE: 0746 Lakes (9345)
DE: 0910 Data processing
DE: 1819 Geographic Information Systems (GIS)
SC: Paleoceanography and Paleoclimatology [PP]
MN: Fall Meeting 2005