The lake deposits in P ock Basin (case studies of Lakes Rakutowskie and oby)

Reconstruction of development of Lakes Rakutowskie and oby in the late Pleistocene and Holocene was the aim of this research. Analysis of content of calcium carbonate, organic matter and C14 datings (7 samples) were done for two cores of sediments of 750 cm long. An average rate of accumulation was counted. Sediments of Lake Rakutowskie show homogeneity along the core which indicates similarity of sedimentation conditions. Sediments of Lake oby were diversified and show variety related to cyclic changes. A common feature is a thick layer of fine sand without carbonate deposited during the older dryas, shown in both cores. The difference in sediment features of both lakes (which have similar depths) indicates that the Lake oby is the more dynamic, filtering element, preceding Lake Rakutowskie in system of water catchment.