Geographia Polonica (1988) vol. 55

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New aspects on the déglaciation chronology of South Sweden

Svante Bjôrck, Björn E. Berglund, Gunnar Digerfeldt

Geographia Polonica (1988) vol. 55, pp. 37-50

Abstract

The absolute dating of the deglaciation in South Sweden has been based on a number of different methods. Among those are 14C-dates on a) marine molluscs, algae, mammals, and sediments, b) limnic sediments and macrofossils, and c) terréstric macrofossils and mammals. Other methods have been to use varved clay connected with the present or local varve-chronologies added to the l4C-chronology. Correlations between the differently dated regions have therefore appeared to be difficult. A correlation method based only on glacial deposits and striations indicated a time-discrepancy between the differently dated deglaciation ages on the west and east coasts. Recent research on the difference between 14C-years and varve-years during the Late Weichselian suggests that much of the found differences between differently dated regions can be explained by steadily increasing l4C production during the deglaciation of South Sweden. The hitherto available data indicate that the time-scales "meet" sometime between 12 700 and 12 800 BP. During the following millennia the gradually higher l4C-activity led to gradually younger radiocarbon dates (relative to varve dates). A partly new, preliminary deglaciation chronology, taking these new data into account, is presented with correlations between the west and east coasts. Differences between regions, regarding deglaciation pattern, are discussed as well as possible glaciodynamic and climatic reasons for these anomalies.

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Svante Bjôrck, Department of Quaternary Geology. Lund University, Tornav, 13, S-223 63 Lund, Sweden
Björn E. Berglund, Department of Quaternary Geology. Lund University. Tornav. 13 S- 223 63 Lund. Sweden
Gunnar Digerfeldt, Department of Quaternary Geology. Lund University, Tornav, 13, S-223 63 Lund, Sweden