Lars Brunnberg

Deglaciation, holocene shore displacement and coastal settlements in Eastern Svealand, Sweden

Abstract Detailed mapping of the clay-varve sediments and stratigraphical analysis of isolated lake basins on the Sodertorn peninsula have been undertaken as part of the research project “Eastern Svealand: Development of the Holocene Landscape”. The varve studies have identified three distinctive stratigraphical units and indicate that deglaciation took place between 11,400 and 10,400 clay-varve years BP. Initially recession of the ice margin was slow but subsequently it became more rapid. Study of 15 isolation basins has allowed a tentative shore displacement curve to be constructed for the area. This curve is marked by varied rates of regression and possibly displays 3 Litorina transgressions. The curve suggests markedly different ages for the transgression events than those proposed by earlier authors and this is assessed in terms of curve construction and dating errors. Archaeological evidence indicates that coastal settlements changed their altitudinal location in response to changes in sea level, this evidence supporting the data derived from isolation basins.

Sedimentology of a glaciofluvial deposit at Ekeby, East Central Sweden

Abstract The Ekeby site, south of Stockholm, has been chosen to elucidate glaciofluvial sedimentation processes soon after the end of the Younger Dryas. Detailed lithofacies and grain-size analyses of gravel, sand and fine sediment sequences in a gravel pit reflect changes in the depositional environment. Four main facies assemblages have been distinguished. The lowermost part of the sequence was probably deposited in a subglacial conduit environment. The middle part of the sequence reflects a transition to a proglacial subaqueous environment. The upper part of the latter sequence probably occurred during increased melting of the ice. The sequence was then covered by beach gravel formed during the regression after the drainage of the Baltic Ice Lake.