Home – Home – Jornals – Geography and Natural Resources 2022 number 4

This article compares three methods of representing micro-charcoal analysis data for studying the thousand-year history of paleofires by using, as an example, microcharcoal data from the bottom sediments of Lake Uzunkol (Ulagan Plateau, Central Altai). The advantages of using the CC index of absolute concentration of microcharcoal per 1 cm³ (Charcoal Concentration) and the CI index for calculating the annual accumulation of microcharcoal per 1 cm² unit area (Charcoal Influx) in lake sediment samples in comparison with data on absolute counts of microcharcoal are proved. The results from applying the CC and CI indexes of microcharcoal to paleocharcoal data from bottom sediments of Lake Uzunkol, covering the time interval from the Late Glacial (17 000 cal. yr BP) till the present, are analyzed. The application of these indexes removes the artificial effect of the increased abundance of microcharcoal in the case of low pollen productivity of steppe landscapes. Results from studying paleomicrocharcoal in bottom sediments of Lake Uzunkol by using the three methods showed that natural fires in Central Altai were most intense in the Holocene during the transitional, unstable climatic period 9500-9000 cal. yr BP, when one type of landscape (steppe) was replaced by another type (forest). That is, forest-steppe landscapes were the most prone to natural fires in the past. By using the CI index, it was found that the development of ancient cultures in the Altai region was accompanied by a general increase in the concentration and accumulation of microcharcoal in lacustrine sediments, starting from 4500 cal. yr BP. A dramatic increase in the concentration and annual accumulation of microcharcoal occurred after 1700 cal. yr BP, which could be caused by an increase in population density in this region of Altai.