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| Titel |
Rare earth element and Nd isotope geochemistry of an ombrotrophic peat bog at Karukinka (Chile, 53.9° S): a palaeo-record of Holocene dust deposition in Tierra del Fuego. |
| VerfasserIn |
Heleen Vanneste, François De Vleeschouwer, Aubry Vanderstraeten, Nadine Mattielli, Delphine Triquet, Natalia Piotrowska, Gaël Le Roux |
| Konferenz |
EGU General Assembly 2013
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250078397
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| Zusammenfassung |
| The value of ombrotrophic peat bogs as past atmospheric dust records, has been increasingly
recognized over the past 10 years. Their high accumulation rates provide high resolution
archives of natural atmospheric dust deposition since the Late Glacial, often missing in
marine, lake and ice core records. Consequently, peat deposits can be used as a proxy for
atmospheric circulation patterns and thus palaeoclimate.
In the Southern Hemisphere, the climate is considered to be driven by the Southern
Westerly Wind belt (SSW), as it significantly affects the Antarctic Circumpolar Current and
hence atmospheric CO2 levels. Palaeo SSW belt migrations have been observed in
palaeoclimate records but, reconstructions of SSW shifts and associated climatic changes are
incoherent, in particular for the Holocene. As peatlands thrive in southwest Tierra del Fuego
due to its high annual precipitation, a remote ombrotrophic peat bog at Karukinka
(southwest on the Isla Grande de Tierra del Fuego) was sampled, to investigate
the Holocene palaeoclimate in southern South America based on dust deposition
records.
A 4,5 m long Russian D-core was recovered and subsequently subsampled for elemental
and isotope geochemistry in addition to density and radiocarbon dating measurements. Initial
results show a number of layers enriched in scandium, indicating the presence of lithogenic
material, i.e. dust. Rare earth element patterns indicate at least 2 different sources. The
most significant dust peak occurs at the base of the core at ~7300 Cal years B.P
and has a neodymium isotopic composition of 2.2, suggesting a volcanic origin. |
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