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| Titel |
New on-line method for water isotope analysis of fluid inclusions in speleothems using laser absorption spectroscopy: Application to stalagmites from Borneo and Switzerland |
| VerfasserIn |
Stéphane Affolter, Dominik Fleitmann, Anna Nele Meckler, Markus Leuenberger |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250091269
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| Publikation (Nr.) |
 EGU/EGU2014-5552.pdf |
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| Zusammenfassung |
| Speleothems are recognised as key continental archives for paleoclimate reconstructions.
They contain fluid inclusions representing past drip water trapped in the calcite structure.
Speleothem can be precisely dated and therefore the oxygen (δ18O) and hydrogen (δD)
isotopes of fluid inclusions constitute powerful proxies for paleotemperature or to
investigate changes in the moisture source over several interglacial-glacial cycles. To
liberate fluid inclusion water and to analyse its isotopic composition, a new online
extraction method developed at Bern is used. The principle can be summarised as
follows: Prior to crushing, the sample is placed into a copper tube, fixed to the
line previously heated to 140°C and flushed with a nitrogen and standard water
mixture. Thereafter, the speleothem sample is crushed using a simple hydraulic
crushing device and the released water from fluid inclusions is transferred by the
nitrogen-standard water mixture flow to a Picarro L1102-i isotopic liquid water and water
vapor analyser. The measuring principle is based on wavelength-scanned cavity ring-down
spectroscopy (WS-CRDS) technology that allows us to simultaneously monitor hydrogen
and oxygen isotopes. Reproducibility of standard water measurements is typically
better than 1.5 ofor δD and 0.4 ofor δ18O. With this method, we successfully
analysed δD and δ18O isotopic composition of a stalagmite from Northern Borneo
(tropical West Pacific) covering almost two glacial-interglacial cycles from MIS
12 to early MIS 9 (460-330 ka) as well as recent samples from Switzerland and
Borneo. These results are used in combination with calcite δ18O to reconstruct
paleotemperature. Currently, we are measuring a stalagmite from Milandre cave (Jura,
Switzerland) covering the Bølling-Allerød, Younger Dryas cold phase and the Holocene. |
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