Dynamics of the Vegetation of Central Yamal in the Holocene

The paper presents new paleobotanical data in combination with the results of radiocarbon dating obtained from organomineral deposits of the northern shore of Pechevalavato Lake (70 degrees 13 ' 22.3 '' N, 71 degrees 50 ' 57.6 '' E) in the Seyakha River basin and characterizing the dynamics of vegetation in the northern part of Central Yamal in the Holocene. It has been shown that a tree birch (Betula sect. Betula) grew in Yamal in the early Holocene (10.2-8.7 cal kyr BP) no less than 400 km north of the modern northern limit of distribution of Betula pubescens ssp. tortuosa. Favorable conditions for the existence of birch woodlands at this time were provided by a higher temperature of the growing season, exceeding the modern parameters of the warmest month of the summer season by approximately 3-4 degrees C. At the end of the early Holocene (after 8.5 cal kyr BP), forest vegetation began to degrade, and open landscapes with diverse plant communities of the subarctic tundra and single trees in the river valley spread. About 6.5 cal kyr BP, the northern subarctic tundra began to form the zonal appearance of the study area in climatic conditions close to modern ones.