DEGLACIATION, SHORE DISPLACEMENT AND EARLY-HOLOCENE VEGETATION HISTORY IN EASTERN MIDDLE SWEDEN

The sedimentary record at Lake Vibysjon, Narke, eastern middle Sweden has been investigated. The lake basin is situated close to the Narke S trait where the main water exchange occurred between the Vanern basin anti Baltic basin during the middle and late phases of the Yoldia Sea stage of the Baltic Sea (c. 10 000-9500 C-14 years BP). The area was d eglaciated in a glaciomarine environment, as reflected by the occurren ce of benthic calcareous fossils (foraminifera, ostracods and the moll usc Portlandia arctica (Gray)) in the lower-most clay units. The estim ated date of deglaciation. 10 440 clay-varve years BP, suggests that a saline bottom-water current entered the Baltic basin shortly after th e high areas south of Lake Vibysjon became free of ice. The brackish w ater fauna occurs during a regional Betula-Empetrum-Hippophae pollen z one, which in southern Sweden is col related with the early Preboreal. The isolation of the Lake Vibysjon basin is dated to 8100 C-14 years BP, and occurred during the last part of the Ancylus Lake stage. Based on investigations of other basins in Narke, it is concluded that the Mastogloia Sea reached c. 62 m a.s.l. and that the Litorina Sea reache d at least 60 m a.s.l. in the area studied.