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| Titel |
Isochron burial dating of the Haslau terrace of the Danube (Vienna Basin) and interlaboratory comparison of sample preparation in Vienna and Budapest |
| VerfasserIn |
Zsófia Ruszkiczay-Rüdiger, Stephanie Neuhuber, Kurt Decker, Régis Braucher, Marcus Fiebig, Mihály Braun, Johannes Lachner, Aster Team |
| Konferenz |
EGU General Assembly 2017
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250142598
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| Publikation (Nr.) |
 EGU/EGU2017-6239.pdf |
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| Zusammenfassung |
| In the Vienna Basin, terraces to the South of the Danube form a staircase with altitudes
ranging between 25 and 130 m above current water level. The terrace system has been
strongly dissected by faults related to the sinistral movement of the Vienna Basin Transform
Fault System [1, 2]. Although each fault block displays a slightly different succession of
terraces, fault-related vertical displacements south of the Danube have not yet been
quantified.
To better understand the Quaternary terrace sequence and its displacement along a fault
segment south of the Danube, the isochron burial dating method [3] based on the 26Al and
10Be cosmogenic nuclide pair has been used on a terrace at Haslau an der Donau (∼40 m
above river level). This terrace is locally the lowest of a staircase of a total of 6 different
levels. Based on geomorphological mapping, its age was considered to be Middle Pleistocene
[4].
The sample set consisted of several quartzite cobbles taken from two sedimentary units
(5.5 m and 11.8 m depth) separated by an erosional hiatus of unknown duration. Six
cobbles were selected for inter-laboratory comparison and processed at both the
Cosmogenic Nuclide Sample Preparation Laboratory at Vienna and at Budapest
[5]. AMS measurements were performed at the French national facility ASTER
(CEREGE, Aix-en-Provence) and at the Vienna Environmental Research Accelerator
(VERA).
Initially, the obtained results show that the 10Be and 26Al concentrations calculated
from the subsamples processed independently using different extraction schemes
at both laboratories overlap within error for all subsamples but one, whose 26Al
concentrations were significantly different. The low 26Al concentration measured in
one Budapest sample probably resulted from Al having been trapped within the
insoluble residues observed after evaporation to dryness. A modification of the sample
processing allows overcoming this difficulty while treating for the following sample
set.
The results demonstrate that the laboratory background is safe for in-situ produced
cosmogenic 10Be and 26Al extraction at both Vienna and Budapest laboratories and that the
different geochemical digestion and purification schemes applied by the two laboratories for
the extraction of 10Be and 26Al lead to similar results.
A preliminary (not corrected) isochron burial age of ∼2.4 Ma was calculated for the
higher sedimentary unit of the Haslau terrace on the basis of the slope of the isochron. This
age is significantly older than the Middle Pleistocene age previously estimated. Further age
determinations are nevertheless necessary to decide whether this preliminary age is accurate
or not.
Thanks to OTKA PD83610, OMAA 90öu17; LP2012-27/2012. INSU/CNRS, the ANR
through the program “EQUIPEX Investissement d’Avenir” and IRD.
References:
[1] Decker et al., 2005. QSR 24, 307-322.
[2] Salcher et al., 2012. Tectonics 31, 1-20.
[3] Balco and Rovey, 2008. AJS 908, 1083-1114
[4] Fuchs and Grill, 1984. Geologische Karte von Wien und Umgebung (1:200.000)
[5] http://www.geochem.hu/kozmogen/Lab_en.html |
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