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Younger Dryas climatic reconstructions in central Poland

Pawłowski D.

Acta Geologica Polonica

2017

Vol. 67, no. 4

567--584

Cladoceran-based paleotemperature estimates for the Younger Dryas for ten sections of paleo-oxbow lakes, valley mires, and lacustrine sediments from central Poland are presented, and their potential usefulness to climatostratigraphy is described. Most of the changes observed in the cladoceran assemblages are responses to climate changes. The cladoceran-based temperature reconstructions reflect cold conditions during the Younger Dryas (YD) and allow a division of this period into two phases: an older colder phase, between 12,800 and 12,000 cal yrs BP, and a younger, warmer phase, between ca. 12,000 and 11,500 cal yrs BP. The geomorphological features of the study sites and local environmental forces are also taken into consideration. The cladoceran-inferred summer temperature estimates from all of the study sites correspond closely with the available climate reconstruction for the YD in central Europe.

Properties and dimensional stability of 12 500-year-old subfossil pine wood

Fejer M., Zborowska M., Adamek O., Dzieduszyńska D., Kittel P., Petera-Zganiacz J., Twardy J.

Drewno : prace naukowe, doniesienia, komunikaty

2014

vol. 57, nr 193

81--95

At the Koźmin Las site, in Central Poland, in the middle section of the Warta River valley, a series of well-preserved tree trunks and in situ stumps, as well as organic deposits, have been found. The tree remains are dated back to the period between 13,000–12,600 cal BP, i.e. to the Alleröd/Younger Dryas transition. The forest consisted predominantly of pines (Pinus sylvestris L.) of a maximum age of approx. 140 years and an average age of 68 years, and the river valley floor was overgrown. The forest was destroyed ca. 12,600 cal BP by deteriorating hydrological conditions or a sudden catastrophic event. The aim of the study was to assess the degree of degradation in terms of selected macroscopic, physical and chemical properties of a subfossil pine log. On this basis, a conservation process was developed, using aqueous solutions of polyethylene glycols (PEG) with varying concentrations of low- and high-molecular polymers. Treated and dried samples were compared in terms of their tangential and radial dimensional stability, as well as their hygroscopic properties.

Younger Dryas Cladocera assemblages from two valley mires in central Poland and their potential significance for climate reconstructions

Pawłowski Dominik

Geologos

2012

Vol. 18, No. 4

237--249

Two sections of sediment from small oxbow-lake infillings located in different river valleys in central Poland were studied by cladoceran analysis in order to examine the response of aquatic ecosystems to the Younger Dryas. Lithological and geochemical records, as well as chydorid (Chydoridae) ephippia analysis were also used to reconstruct Younger Dryas climate trends. A high concentration of cladocerans, as well as the presence of Cladocera taxa preferring warmer water, was found. It is likely that local processes in the oxbow lakes were important, because the presence of warm-preferring taxa was also related to their habitats and their development. Yet local environmental forces, such as the influence of the rivers, habitat modification, macrophyte abundance, and eutrophication, were not only major factors to affect the Cladocera diversity in the Younger Dryas. The observation of changes in the composition and concentration of Cladocera in oxbow-lake infillings indicates that most of the changes occurred in response to climate changes.