Kol-14 datering : En litteraturstudie över hur kol-14 isotopen används för datering, samt utveckling och tillämpning av djup-åldersmodeller inom naturgeografin.
2013
Magnusson, Erik
This literature study concerned the use and function of the radioactive isotope carbon-14, as a dating method of organic material, within the scientific field of physical geography. In this report it is presented the need of atmospheric calibration curves and the development of these as a necessity to translate carbon-14 years to calibrated calendar years. A number of common age-depth models that is used to give an approximation of an accumulation sequence and its related dates over the actual time period in different natural archives is presented and discussed. Different problems that commonly occur when age-depth models are utilized as for instance reservoir effects, contaminations or other age deviations are addressed and analyzed. The software CLAM in presented and discussed and was also used to produce age-depth models. In order to test the impact of different age-depth models used to date the immigration of Picea Abies in the Swedish landscape during Holocene, five lake sediment cores and their pollen profiles was remodeled using CLAM. The outcome of the remodeling suggest that the impact of choosing “wrong” age-depth model was of little importance for these chosen lakes, as the deviating ages between the statistically best and the statistically worst model, was just 2% on average. Calendar years derived from carbon-14 dating should not be considered an absolute truth as it is always an uncertainty involved, and the choice of age-depth model for dating a sequence should be based on scientific knowledge of the actual area.
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