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Age of terrace levels and palaeomeander systems in the light of overestimated radiocarbon datings (the case study of the Dniester River valley, West Ukraine)

Gębica Piotr, Jacyšyn Andrij

Studia Geomorphologica Carpatho-Balcanica

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2021

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Vol. 55

99--128

EN

In the Dniester valley within the Halyč-Bukačivci Basin, there are the Late Vistulian terrace, 6.5–5.5 m high (above the riverbed), large palaeomeander from the Late Vistulian decline (Younger Dryas) and two Holocene terraces 4–5 m and 3–4 m high. The results of conventional radiocarbon dating admittedly indicate a consistent and logical arrangement from the oldest dates (13.01–12.45 ka BP) for the Late Vistulian terrace and the large palaeomeander to more and more younger ones (8.6–7.89 ka BP) for the distinguished systems of the Holocene palaeomeanders; however, they are generally significantly older compared with findings from palynological analyses. The overestimation of the age of sediments is much greater for the Subboreal and Subatlantic generations of palaeomeanders than for the Late Vistulian large palaeomeander of the Dniester river. The error of radiocarbon dates may be caused by the admixture of older re-deposited organic material or, more likely in the case of the profiles concerned, by the reservoir effect (hard water effect) associated with the presence of old carbonates. Based on the presented analysis, there is a reasonable supposition that some of the existing radiocarbon dating of the Late Vistulian palaeomeander fills may be significantly overestimated.

2

Reconstruction of atmospheric lead and heavy metal pollution in the Otrębowskie Brzegi peatland (S Poland)

Pawełczyk Fatima, Bloom Karolina, Jucha Witold, Michczyński Adam, Okupny Daniel, Sikorski Jarosław, Tomkowiak Julita, Zając Ewelina, Fagel Nathalie

Geological Quarterly

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2019

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Vol. 63, No. 3

568--585

EN

We reconstruct palaeoenvironmental changes since the Late Holocene in the Orava-Nowy Targ Basin, with an emphasis on anthropogenic influence (Walker et al., 2018). This reconstruction employs multiproxy analyses of the Otrębowskie Brzegi poor fen. We combined radiocarbon and 210Pb dating with elemental geochemistry, stable lead isotopes, and palaeobotanical analyses. The core we investigated covers a period from 4200 ± 100 BC to the present, with a peat accumulation rate varying between 0.001 and 0.243 cm y-1. Heavy metal concentrations, Pb isotopic ratios, and a palynological analysis revealed a significant impact of human activities in the past. The highest concentration and accumulation rate of Pb, were found around 1950 AD. The 206Pb/207Pb quotient ranged between 1.168 and 1.223, with average value around 1.198. Most of the interpretation was based on Pb and its stable isotopes; however, other elements were also important indicators of natural and anthropogenic environmental changes. Our results revealed similarities between the geochemical composition of the peatland studied and other peatlands from the Orava-Nowy Targ Basin.

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Ewolucja środowiska w rynnie jeziora Jasień w obrazie palinologicznym i zmian fauny Cladocera

Miotk-Szpiganowicz G., Niska M.

Landform Analysis

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2008

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Vol. 7

102--112

PL

Na obszarze rynny jeziora Jasień zlokalizowano cztery stanowiska, dla których wykonano analizę palinologiczną i analizę szczątków Cladocera. Celem badań było odtworzenie przemian środowiska przyrodniczego na tym terenie. Rdzenie, z których pobrano próby do analiz, składały się głównie z osadów typu gytia i torf. Próbki do analiz wykonywano według standardowych procedur. Do obróbki danych liczbowych wykorzystywano program POLPAL. Otrzymane wyniki palinologiczne umożliwiły odtworzenie historii roślinności badanego terenu począwszy od okresu borealnego, a analiza szczątków Cladocera dostarczyła informacji o fazach rozwoju części zbiornika jeziornego Obrowo Duże.

EN

In order to reconstruct the environmental history of the Jasień Lake trough, pollen analysis and an analysis of Cladocera remains have been simultaneously carried out. Sediments for pollen research have been collected in the bay section of the Jasień Lake and in the Obrowo Małe peat bog. Cladocera remains have been sampled in two sites within a peat bog adjacent to the Obrowe Duże Lake. Preparation of samples for both analyses followed standard procedures. Numerical data have been elaborated using the POLPAL software. The results of the palynological study have allowed to decipher vegetation history since the Boreal period. The peat bog of Obrowo Małe began to form at the onset of the Atlantic period. Cladocera remains yielded information about phases of water body evolution in the part of the Obrowo Duże Lake, which subject to silting transformed into a low-level valley bog, and then into a transitional peat bog. Pollen and Cladocera analyses have been carried out on material collected at dissimilar sites, which practically excludes the possibility of correlation of results and allowed one only to reconstruct the major hydrological changes, common for the entire region. In the latest Holocene, in the Jasień Lake trough a trend towards water level decrease is observed due to both climatic and human impact. Further changes included the rise of trophic level in the lake and vegetation succession onto the shallower parts of the lake.

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Tree stumps from the bottom of the Vistula Lagoon as indicators of water level changes in the Southern Baltic during the Late Holocene

Łęczyński L., Miotk-Szpiganowicz G., Zachowicz J., Uścinowicz S., Krąpiec M.

Oceanologia

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2007

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No. 49 (2)

245-257

EN

The Vistula Lagoon is situated along the south-eastern shore of the Gulf of Gdansk and is linked with the gulf through the Strait of Baltiysk. Separated from the open sea by the Vistula Spit, the Vistula Lagoon is a shallow body of water with a mean depth of 3 m; the bottom is covered with a layer of mud several metres thick. This article presents a unique, newly discovered locality of tree stumps occurring in situ at the bottom of the Vistula Lagoon. The radiocarbon age of the alder stumps and the top of the peat in which they are rooted is Subboreal. The alder wood was dated to 4770š35 and 3295š35 years BP. The top layers of peat were dated to 4670š40, 4410š35 and 3690š35 years BP. The considerable scatter of the dates indicates the significance of erosional processes during marine transgressions. Radiocarbon dates and pollen analyses indicate that in the late Atlantic - early Subboreal periods, the water level of the Vistula Lagoon was about 3 m lower than it is today. The -2 m level was passed no earlier than c. 3500 years ago; the -1 m level was reached around 2000 years ago.

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New age data of buried peat deposits from the site "Fili Park" (Moscow, Russia) by the uraniumthorium dating and palynological analysis and its stratygraphic significance

Kuznetsov V. Yu., Arslanov K. A., Alekseev M. N., Pisareva V. V., Chernov S. B., Maksimov F. E., Baranova N. G.

Geochronometria

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2002

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Vol. 21

41-48

EN

The chronostratygraphically important Quaternary buried peats from the site "Fili Park" (located on the territory of Moscow) on the Russian Plain were studied by the methods of uranium-thorium dating (UTD) and palynological analysis. The deposits under study were the subject of intense debate: some number of the palynologists assigned ones to the Mikulino (Eem) Interglacial, while the another investigators - to the Odintzovo Interglacial (Middle Pleistocene). Detailed palynological study gave the possibility to mark out the 3 palynozones (M2, M3 and M4) in section vertical profile and refer the deposits to the Mikulino (Eem) Interglacial. The uranium-thorium dating (by "leachate alone" method) was carried out in the middle layers, which would be expected to be a closed system in respect to uranium and thorium isotopes. The direct uranium-thorium dating of inner layers showed the first UTD ages from 78.9 to 105.0 ka for deposits from the site "Fili Park". The corrected uranium-thorium age of buried peat turned out to be younger than the currently adopted boundaries of the last Interglacial (116-128 ka) and comprised 89š11 ka. There was probably an additional post-deposition uranium uptake in the internal section layers that in general have led to an underestimated age value. Nevertheless, we refered these questionable in chronostratigraphic respect deposits to the Mikulino Interlacial. The geochronological data obtained were compared with the uranium-thorium dating results (113š11 ka) for the closed geochemical samples from the Mikulino (Eem) Interglacial peats of the stratotypical section "Mikulino" (Russian Plain). This comparison confirmed the reliability of our conclusions.