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The record of postglacial environmental changes of the southern Baltic coastal zone in the sequence of fossil soils

Kruczkowska, Bogusława, Jonczak, Jerzy, Gadziszewska, Joanna, Niska, Monika, Florek, Wacław, Degórski, Marek
Journal of soils and sediments 2019 v.19 no.2 pp. 848-861
Cladocera, Holocene epoch, coasts, fossil soils, fossils, lakes, permafrost, physicochemical properties, pollen, radiocarbon dating, research methods, shorelines, surface water, water reservoirs, wildfires, Baltic Sea
PURPOSE: The studies aimed to reconstruct major phases of litho-morpho-pedogenic processes and past environmental changes in the Baltic coastal zone near Poddąbie (54°37,070′ N, 16°57,897′ E) based on physical, chemical, pollen, and fossil Cladocera analysis of the polycyclic pedocomplex. MATERIALS AND METHODS: The polycyclic pedocomplex under study included seven fossil soils developed from the Early Holocene until modern times from various materials. The soils were sampled and analyzed using standard procedures in soil science to determine their physical and chemical properties. Pollen and fossil Cladocera analysis was also carried out in the examined profile. Radiocarbon dates of selected samples were also specified. RESULTS AND DISCUSSION: The studied polycyclic pedocomplex has been developed from materials of varied origin, including glaciofluvial, fluvial, aeolian, and biogenic deposits of the lake. According to the results of pollen and fossil Cladocera analysis and radiocarbon dating, this body of water has evolved from the beginning of Preboreal period to the half of Boreal. The studied soils represent various reference groups and advancement of development. They constitute relics of former geomorphological and soil-forming processes, which have taken place over the last 9500 years, including periglacial processes, wildfires, Baltic Sea shoreline changes, and aeolian activity. The last stage of the coastal relief dynamics was conditioned by the fire which took place about 1472–1637 AD. The lack of plant cover and intensive abrasion due to direct vicinity of the coastline has caused the deposition of aeolian material, which is the parent material of nutrient-poor initial soils. CONCLUSIONS: The analysis of fossil soil development with the use of specialized research methods allowed for reconstructing the dynamics of past geomorphological processes and natural environment changes in the study area. The studied polycyclic pedocomplex constitutes a record of environmental changes taking place in the central part of the Polish Baltic coastal zone from the Early Holocene to the present day. The studied soil sequence is located within a land depression developed in place of the former water reservoir created as a result of permafrost degradation, and filled with Holocene deposits.