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| Titel |
Hydrogen isotopes on organic compounds express large hydrological changes in
the Mio-Pliocene of the Dacian Basin (Romania) |
| VerfasserIn |
Iuliana Vasiliev, Gert-Jan Reichart, Wout Krijgsman |
| 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 |
250130695
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| Publikation (Nr.) |
 EGU/EGU2016-10990.pdf |
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| Zusammenfassung |
| During the late Miocene to Pliocene (∼11 to 3 Ma) large part of the southern Eurasian
interior was covered by the Eastern Paratethys epicontinental sea. The western most part of
the Eastern Paratethys was occupied by the Dacian Basin, in the foredeep of the Carpathians.
The active subsidence in the front of the Carpathians led to the fast accumulation of up to 10
km think sedimentary load in the Dacian Basin, all during the latest Miocene and Pliocene.
These deposits are now tilted and well exposed along river section in the Carpathian
Foredeep. Here we are reconstructing the large-scale changes of hydrologic budget in the
Dacian Basin area over a long time interval (8 to 2.5 Ma). The sampled Rîmnicu Sărat
Valley section covers the Messinian salinity crisis interval, times when the adjacent
Mediterranean basin suffered severe restrictions of its connections to the Ocean and,
subsequently was flooded by the Atlantic at the beginning of Pliocene. We are using
compound-specific hydrogen isotopic composition (δD) measured on n-alkanes produced
by plant waxes. We focus our analysis on long-chained δDn−alkanes (n-C27 to
n-C33) derived from the vascular plant waxes. The saturated hydrocarbon fraction of
the extractable organic matter identified in the a-polar fraction of Rîmnicu Sărat
Valley is dominated by a homologous series of n-alkanes ranging from n-C16 to
n-C35. The long-chain (>C25), predominantly odd-carbon number homologues are
prevailing which is typical for terrestrial higher plant derived n-alkanes, indicating an
important terrestrial organic matter input. The ∼ 60 ‰ amplitude of changes for seven
consecutive sampled levels measured from both δDn-C17−21 and δDn-C27−31
can be majorly explained by significant changes in the stable hydrogen isotope
ratios characterizing the Dacian basin waters and the meteoric waters reaching the
Dacian Basin. This indicates that the hydrological regime in Dacian paleo-basin has
significantly varied, with heaviest δD values being recorded from a time-interval
corresponding to the exceptionally dry Messinian salinity crisis of the Mediterranean. |
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