High-Resolution Age-Depth Model of a Peat Bog in Poland as an Important Basis for Paleoenvironmental Studies

Abstract

This article focuses on constructing a high-resolution age-depth model for the Puścizna Mała peat bog located in Orawa-Nowy Targ Basin (S Poland). The chronology was established on the basis of both210Pb and14C measurements, and further confirmed by pollen diagrams and the peat bulk composition (density, ash content, and measurements of C, N, S). The137Cs profile revealed significant downward migration of this radionuclide and was not suitable for geochronological interpretation. The peat profile in southern Poland records almost 2000 yr of paleoecological and geochemical changes. Major historical events linked to anthropogenic and climatic changes are recorded in the investigated proxies, which confirm the reliability of the age-depth model. Specifically, the Roman period, Migration period, Medieval times, as well as the Industrial Revolution are reflected in the palynology and bulk composition of the peat. However, dating results obtained for the core segment between 22–45 cm are problematic when confronted with other analyses. The highest peat accumulation rate of 2 mm yr-1(AD 1300–1400 according to the age-depth model) is not compatible with the section of the highest peat decomposition revealed by lithological description. Moreover, the onset of a drastic decline of forests reflected in the palynological data and dated to AD 1280–1340 (40 cm) is difficult to explain in the light of historical data. Therefore, the lithology, bulk density, and pollen were used to validate the obtained age-depth model. External forcing factors on the peat formation process may be indicated, including agricultural activity, water-level fluctuations, and natural climatic factors, which paradoxically caused doubling of the obtained peat accumulation rate.