Chronology and directions of Late Glacial paleoenvironmental changes: A multi-proxy study on sediments of Lake Słone (SE Poland)

Abstract

The article presents the results of a multi-proxy study on sediments of Lake Słone (Chełm Hills) located in the northern peripheral area of the Lublin Upland (SE Poland). The area remained in the periglacial zone (with permafrost present in the geological substrate) during the last glaciation. This paper represents an attempt to determine the directions and intensity of changes in environmental conditions during the Late Glacial. It also attempts to reconstruct lake development conditions within the area unaffected by the extent of the ice sheet. The aim of the study was to investigate bottom sections of two sediment profiles representing the period of Late Glacial lake-mire sedimentation occurring in varying thermal and humidity conditions. Conditions were indicated by lithological variations in the sediments and the content of micro and macrofossils. The latter were identified based on palynological and malacological analyses, as well as by subfossil Ostracoda and Cladocera analysis. The chronology of the identified paleoenvironmental changes was determined based on the results of paleobotanical analysis in correlation with radiocarbon dating (conventional and AMS) of the selected sediment layers. The results were compared to other sites from north-central Europe and to the well-dated laminated sediments sequences from the nearest Late Glacial site at Perespilno. It was estimated that the development of Lake Słone probably had its origin in the Older Dryas. The development of the lake basin, in turn, is associated with specific processes of disappearance of permafrost in the Upper Cretaceous bedrock.