Charcoals in the middle taiga podzols of Western Siberia as an indicator of geosystem history

A middle-taiga iron-illuvial podzol (Glossic Endogleyic Albic Podzol) was studied on an ancient eolian dune in the Bol’shoi Yugan River basin (the Ob’ River tributary, Surgut region), near the large-scale archaeological research site. The radiocarbon age of 31 charcoals was determined, and 8 variants of the location of charcoal-containing soil zones relative to other morphological patterns were identified. It was proved that charcoal can help in dating the time of mosaic pattern formation, and the development of podzolic horizon coincided with intense wildfires in the second half of the Holocene. It was found that charcoal-containing soil zones first appeared in soils about 5 ka ago. Charcoals older than 5 ka cal. BP were not found. Pyrogenic events became twice more frequent at the beginning of the third millennium BP, with their maximum in the middle of the third millennium BP. The frequency of pyrogenic events decreased noticeably at the very end of the second millennium BP. Many peaks of pyrogenic events during the last five millennia coincided with the periods of archaeological cultures. An assumption that the continuous existence of forest environment leads to the permanent burial of charcoal due to fall of a tree accompanied by its uprooting was partially confirmed.