Kimmo Tolonen , Goran Possnert, Högne Jungner, Eloni Sonninen, Jukka Alm

High resolution 14C dating of surface peat using the AMS technique

Tolonen K., Possnert G., Jungner H., Sonninen E., Alm J. High resolution 14C dating of surface peat using the AMS technique.

Tiivistelmä

In an AMS (accelerator mass spectrometric) determination of 14C from moss-increment dated samples from a Sphagnum fuscum hummock, a clear peak representing the time of high 14C activity in the atmosphere due to nuclear bomb tests was found. The 14C activities in the peat profile at deeper levels, corresponding to the period down to 1600 BP, showed similar variations as the atmospheric values. The time-scale obtained from radiocarbon dating fitted well with results from moss-increment counting, pollen analysis and dendrochronological dating of a fire horizon. Using the bomb activity peak, the fraction of carbon emanating from deeper layers and refixed into growing peat was estimated. The fraction of soil carbon dioxide taken up by the contemporary Sphagnum sward was thus found to be in the order of 20%. Keywords: Moss increment dating, peatlands, radiocarbon, Sphagnum

Avainsanat
Sphagnum; peatlands; Moss increment dating; radiocarbon

Vastaanotettu 31.10.2017 Julkaistu 1.1.1992

Katselukerrat 2239

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