Wyniki wyszukiwania - Biblioteka Nauki

Nowa wersja platformy, zawierająca wyłącznie zasoby pełnotekstowe, jest już dostępna.
Przejdź na https://bibliotekanauki.pl

Ograniczanie wyników

Znaleziono wyników: 4

Liczba wyników na stronie

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych: palynological analysis

Sortuj według:

Ogranicz wyniki do:

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

100%

Gębica P. , Jacyšyn A.

tom Vol. 55

99--128

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.

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

88%

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

tom No. 49 (2)

245-257

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.

Pollen morphology of Ukrainian species of the genus Pedicularis L. (Orobanchaceae Vent.)

63%

Peregrym O. M. , Tsymbalyuk Z. M. , Mosyakin S. L.

tom 24

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

63%

Leczynski L. , Miotk-Szpiganowicz G. , Zachowicz J. , Uscinowicz S. , Krapiec M.

nr 2

The Vistula Lagoon is situated along the south-eastern shore of the Gulf of Gdańsk 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 4770±35 and 3295±35 years BP. The top layers of peat were dated to 4670±40, 4410±35 and 3690±35 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.