Palaeoenvironment of the Upper Kama Region during the Late Glacial and Early Holocene (Novozhilovo Lake Sediments Case Study)

For the first time, a high-resolution record of natural events of the Late Glacial and Early Holocene (14150–9730 cal BP) was obtained for the Upper Kama basin based on sedimentary succession in Novozhilovo Lake (Kama–Keltma lowland). The results of the reconstruction of sedimentation setting, based on paleobotanical and sedimentological analyses, as well as radiocarbon dating, are presented. The beginning of formation of the lake was apparently preceded by a period of predominantly alluvial morpholithogenesis, which presumedly corresponded to the Late Pleniglacial. There are four stages in the evolution of the lake basin: the first three were characterized by lacustrine-alluvial sedimentation that was predominantly minerogenic, and the fourth stage was marked by typical lacustrine organogenic sedimentation. The first stage covered the Bølling–Allerød interstadial period from 14 150 to 13 500 cal BP, which was characterized by the accumulation of sand under conditions of high water flow. At the Allerød–Younger Dryas boundary, bioproductivity increased significantly. During the second stage (13 500–12 420 cal BP), water exchange slowed down and organomineral lake sediment formed. The third stage of the transitional sedimentation refers to the Younger Dryas–Early Holocene (12 420–10 700 cal BP). During that time, alluvial inputs predominated, with a decrease in the organic matter content. Finally, the fourth stage of the eutrophic lake (10 700–9730 cal BP) was characterized by a high organic matter content in the sediment and the aleurite fraction increased in the grain-size composition.