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

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.

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Opracowanie rekordu ze środków MNiSW, umowa Nr 461252 w ramach programu "Społeczna odpowiedzialność nauki" - moduł: Popularyzacja nauki i promocja sportu (2021).