Unknown
University of California Press
In:
In: Radiocarbon dating: proceedings of the 9th International Conference Los Angeles and La Jolla 1976. , ed. by Berger, R. University of California Press, Berkeley, California, USA, pp. 453-469.
Publication Date:
2018-06-19
Description:
Coastal marine sediments from different environments were investigated for natural radiocarbon isotope concentration: from the Fladenground area(northern North Sea), from
the tidal flats off the western coast of Schleswig-Holstein, northern Germany, from Kiel
Bight(western Baltic Sea), and from the Bornholm Basin(southern Baltic). Sediment sampling, pretreatment, and wet oxidation technique with sedimentary organic carbon are outlined. Organic matter as well as carbonates of coastal marine sediments are found to be composed of differently aged fractions. Sediment surface ages range between 800 years in the Baltic and 5000 years in the Fladenground area. In spite of these redistribution effects, however, the effective 14 C-age of the sediments is highly reproducible for a given environment. Minor variations are caused by varying supply of recent organic matter. In recent time dead carbon from fossil fuels and man-made 14 C from the nuclear weapon tests have entered the sedimentary environment ("ash-effect" and "bomb-effect"). For the Bomholm sediments the age composition of the organic matter could be
analyzed in greater detail. The recent carbon fraction varies by a factor of 2.6 during the
last 70 years, from 0.5% to 1.3% of sediment dry weight, and may be as low as 10% of
total C-org content. The "eroded" fraction amounts to 3.6% of dry weight, the effective
age being about 1500 years, and fossil fuel carbon is about 0.2% to 0.3% on dry weight
basis.
Type:
Book chapter
,
NonPeerReviewed
Format:
text
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