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Titel |
Dating of pollen samples from the sediment core of Lake St Anne in the East
Carpathian Mountains, Romania |
VerfasserIn |
Katalin Hubay, Enikő Katalin Magyari, Mihály Braun, Frank Schäbitz, Mihály Molnár |
Konferenz |
EGU General Assembly 2016
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Medientyp |
Artikel
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Sprache |
en
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Digitales Dokument |
PDF |
Erschienen |
In: GRA - Volume 18 (2016) |
Datensatznummer |
250131816
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Publikation (Nr.) |
EGU/EGU2016-12260.pdf |
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Zusammenfassung |
Lake St Anne (950 m a.s.l.) is situated in the Ciomadul volcano crater, the youngest volcano
in the Carpathians. Aims driving forward the studies there are twofold, one is dating the latest
eruption of the Ciomadul volcano and the other is the multi-proxy palaeoenvironmental
reconstruction of this region. The sediment of Lake St Anne was sampled several
times already, but never reached the bottom of the lake before. During the winter
of 2013 at a new core location drilling started at 600 cm water depth and finally
reached the bottom of the lake sediment at approximately 2300 cm including water
depth.
As for all multi-proxy studies essential requirement was to build a reliable chronology.
Sediments were dated by radiocarbon method. Previous radiocarbon dates were measured on
plant macrofossils, charcoal, Cladocera eggs, chironomid head capsules and bulk lake
sediments. Lake St Anne has volcanic origin and there is intensive upwelling of
CO2it is important to study and take into consideration, whether there is any local
reservoir effect at the case of samples where it could be problematic. Furthermore the
late part of the sediment section (between 15,000 and 30,000 cal. yr BP) has low
organic matter content (less than 2-4%) with scarcity of datable plant macrofossil
material.
In this review a different fraction of pollen samples with terrestrial origin was tested and
studied as a novel sample type for the radiocarbon dating. Pollen samples were extracted
from the lake sediment cores. This type of organic material could be an ideal candidate for
radiocarbon based chronological studies as it has terrestrial source and is present in the whole
core in contrast with the terrestrial macrofossils.
Although the pollen remains were present in the whole core, in many cases their
amount give a challenge even for the AMS technic. Samples were measured with
EnvironMICADAS AMS and its gas ion source in the HEKAL laboratory (Debrecen,
Hungary).
We examine the reliability the radiocarbon dates given from different pollen fractions and
their compatibility to the previously measured radiocarbon dates from macrofossil and other
dated materials.
Acknowledgement
E.K. Magyari acknowledges the support of the Humboldt Fellowship. |
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