Identification and ¹⁴C-dating of Quaternary wood samples dredged from groundwater-filled gravel pits in the UNESCO World Heritage Landscape of Lake Neusiedl (Northern Burgenland, Austria)

Autor(en)

Hermann Häusler, Otto Cichocki, Eva Maria Wild, Peter Steier

Abstrakt

In the lowlands of eastern Austria, the Quaternary deposits are underlain by Neogene formations of the Danube/Kisalföld Basin that in turn forms the westernmost bay of the Miocene Central Paratethys. The younger Middle Pleistocene to Holocene deposits of the UNESCO World Heritage Landscape of the Nationalpark "Neusiedler See - Seewinkel"are known as the Illmitz Formation. In the Seewinkel Plain, this formation covers an area of 350 km² and comprises deposits from a few meters to 20 m thick, which are interpreted as sediments of an anastomosing river system. Youngest finegrained lacustrine deposits of the Illmitz Formation below salt pans near Podersdorf am See range from ∼11 000 calibrated years Before Present (cal BP) to ∼8 000 cal BP. Hence also comparable young coarse-clastic channel deposits of the Illmitz Formation were expected. Wood samples dredged from gravel pits in the Seewinkel Plain in the years 1988 and 1996 yielded radiocarbon ages ranging from ∼43 600 cal BP to ∼32 500 cal BP. In contrast, recently dredged wood remains yielded minimum radiocarbon ages exceeding ∼50 000 years. Surprisingly, older deposits of the Seewinkel Plain were dated from both surface of gravel pits and subsurface of salt pans. On the one hand, fine-clastic deposits on top of Seewinkel gravel pits were luminescence dated ∼100 to ∼55 ka. On the other hand, the deposition of a salt-bearing gravelly silt, the so called "salt-bearing horizon"below salt pans was attributed to MIS 5e (∼130 to ∼115 ka). Therefore, the wood remains with minimum radiocarbon ages of over 50 000 years probably were deposited in younger channel fills between the salt-bearing horizon and the luminescence dated fine-clastic deposits. Ultimately, it cannot be ruled out that at the base of the Illmitz Formation older wood remains were relocated either from fluvial deposits of paleo-Danube that date back to the Early Pleistocene or from underlying lignite-bearing deposits of Late Neogene. Overall, the multitemporal deposition of woods in climatically changing environments since the beginning of the Rissian glaciation (∼MIS 11) may have spanned a period of approximately 400 000 years. Wood anatomical studies allowed identifying several species, among them climatically indifferent taxa as, e.g., Larix/Picea (larch/spruce) and Pinus (pine) as well as thermophilous ones such as Fraxinus (ash), Ulmus (elm) and Quercus (oak). Decimeter-sized dark brown coalified wood residues with rounded edges were dredged from the base of gravel pits. The dark color of wood remains indicates either a completely different chemical environment at the base of the Illmitz Formation or more probably a much longer exposure time in fluvial deposits than for the light brown wood samples.

Organisation(en)

Department für Umweltgeowissenschaften, Institut für Urgeschichte und Historische Archäologie, Isotopenphysik

Journal

Austrian Journal of Earth Sciences

Band

118

Seiten

61-73

Anzahl der Seiten

13

ISSN

0251-7493

DOI

https://doi.org/10.17738/ajes.2025.0003

Publikationsdatum

01-2025

Peer-reviewed

Ja

ÖFOS 2012

105101 Allgemeine Geologie, 103014 Kernphysik

Schlagwörter

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/9652a76f-125d-4ed5-85b4-6fa1255fba5c