Artikkelit kirjoittajalta Jukka Alm
High resolution 14C dating of surface peat using the AMS technique.
Tiivistelmä |
Näytä lisätiedot
|
Artikkeli PDF-muodossa |
Tekijät
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
-
Tolonen,
Dept. of Biology, Univ. Joensuu, P.O. Box III, FIN-80101 Joensuu, Finland
Sähköposti:
ei.tietoa@nn.oo
- Possnert, Sähköposti: ei.tietoa@nn.oo
- Jungner, Sähköposti: ei.tietoa@nn.oo
- Sonninen, Sähköposti: ei.tietoa@nn.oo
- Alm, Sähköposti: ei.tietoa@nn.oo
Determination of recent apparent carbon accumulation in peat using dated fire horizons.
Tiivistelmä |
Näytä lisätiedot
|
Artikkeli PDF-muodossa |
Tekijät
Two charcoal layers, originating from two forest fires, were found at between 7 and 58 cm in the peat of Lakkasuo mire. Using dendro-chronological techniques and fire scars on Scots pine {Pinus sylvestris L.) stumps, the date when these two layers was deposited could be estimated. The earlier fire swept over the mire about 1780 A.D. and the later fire, which seems to have been limited to the eastern part of Lakkasuo, occurred in 1845 A.D. Knowing the thickness of the peat layer above the dated charcoal layers, its bulk density and carbon content, the rate of carbon accumulation during the last 212-147 years could therefore be calculated for different site types in the Lakkasuo mire complex. These values ranging from 39.8 to 80.7 g C m-2 a-1. can be compared to those (28.5-42.8 g C m-2 a-1 ) 0f the peat layer down to a still older fire horizon dated using the AMS radiocarbon "wiggle matching" technique at 1040 ± 90 B.P.
Keywords: Carbon accumulation, charcoal, dating, dendrochronology, fire
-
Alm,
Department of Biology, University of Joensuu, P.O. Box 111, FIN-80100 Joensuu, Finland
Sähköposti:
ei.tietoa@nn.oo
- Tolonen, Sähköposti: ei.tietoa@nn.oo
- Vasander, Sähköposti: ei.tietoa@nn.oo
Click this link to register to Suo - Mires and peat.
Jos olet rekisteröitynyt käyttäjä, kirjaudu sisään tallentaaksesi valitsemasi artikkelit myöhempää käyttöä varten.
Valitsemasi artikkelit
Suo - Mires & Peat
