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Variable isostatic uplift patterns during the holocene in southeast Sweden, based on high-resolution ams radiocarbon dating of lake isolations - a preliminary interpretation

Risberg J., Alm G., Goslar T.

Polish Geological Institute Special Papers

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2008

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Vol. 23

77-80

EN

To describe changes in shoreline configuration in northern Uppland, south-east Sweden, the isolations of 17 present and overgrown lakes have been interpreted from diatom analysis and AMS radiocarbon dates on terrestrial macrofossils. The sites studied are spread c. 60 km in east-west and c. 70 km in north-south direction. The oldest isobase direction, representing the "Neolithic Sea", extends in more or less north-south direction. The present day isobase system shows a clear east-west trend. The results indicate a complicated pattern of isostatic uplift during the late Holocene. We have defined five different shore displacement curves denoted A–E. It is obvious that the present day east-western isobase system is not valid for the investigated sites. Instead, the north-south isobases for the "Neolithic Sea" should to a relatively high degree explain the geographic distribution of sites. It is suggested that a re-direction of the isostatic uplift pattern has occurred sometime during the last c. 5000 years. This shift could have taken place as a slow deformation of the bedrock and/or as neotectonic movements along existing fault lines.

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Too old ams radiocarbon dates obtained from moss remains from Lake Kwiecko bottom sediments (N Poland)

Madeja J., Latowski D.

Geochronometria

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2008

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Vol. 32

13-19

EN

The paper presents the results of the AMS radiocarbon dating of moss macrofossils which seem to be too old in the context of palynological data. The lack of agreement between the obtained results of radiocarbon dating and pollen analysis has been discussed. Some possible causes of the discrepancies between the results of radiocarbon dating and palynological dating have been given.

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Chronostratigraphy of calcareous mire sediments at Zawadówka (Eastern Poland) and their use in palaeogeographical reconstruction

Dobrowolski R., Hajdas I., Melke J., Alexandrowicz W. P.

Geochronometria

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2005

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Vol. 24

69-79

EN

Holocene evolution of the cupola spring mire at Zawadówka is presented, which is located in the borderland of the Lublin Upland and Volhynia Polesie (E Poland). Based on the results of sedimentological, malacological, geochemical analyses, and AMS radiocarbon dating, four main sedimentation stages are distinguished, which were associated with regional variability of humidity and temperature in the last 10 ka BP and with human activities in the last 200 years.

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Sample preparation in the Gliwice Radiocarbon Laboratory for ams 14C dating

Goslar T., Czernik J.

Geochronometria

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2000

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Vol. 18

1-8

EN

The Accelerator Mass Spectrometry has been used in 14C dating for several years. The 14C concentration is measured in graphite target. In the Gliwice Radiocarbon Laboratory a system to produce graphite targets has been built. This system will be used for 14C dating of terrestrial plant and zooplankton macrofossils in lake sediments, and later, in routine 14C dating of small samples.