Using U/Th-dating made it possible to detect traces of interstadial in West Siberia, correlated with brehrup interstadial of West Europe. U/Th-date of 105,5±3,6/3,3 thous. years using method of leaching (L/L), and of 104,4±4,4/3,9 thous. years using total solution data (TSD) was determined in the “lower peat bog” of Kiryas key section (Surgut Low Ob basin — West Siberian extraglacial zone through Zyrjanka glaciation). In the said section, below the strata of Kargino (middle Wurm) horizon (which lower stratum having 14Ñ-date of 46 350±1590 years) one could observe traces of two Interglacial periods and three stages of Zyrjanka glaciation. Obtained, prolific palaeobotanical data from the “lower peat bog”. It is shown that through the optimum of “Siberian brehrup”, subject to expansion in the Surgut Low Ob basin was north taiga, with palaeoclimate of “Siberian brehrup” being colder than modern one, though warmer than through the optimum of Kargino Time. Analysis of palaeobotanical data from the key section of Kazantsevo horizon in Middle Siberia (Bhedoba) made it possible to distinguish strata of “Siberian brehrup” in the upper part of buried peat bog of the said section, testifying to a possibility of their interregional expansion.

 Completed, comprehensive palaeogeographic investigations of the Tura-and-Pyshma interfluve, basing on sites of Late Bronze and Early Iron Age (Xth–IVth cc. B.C.). For the first time, subject to simultaneous use being palaeosoil, palynological, and microbiological methods to investigate palaeosoils under barrow-mounds and cultural layers. It was established that during the discussed period natural conditions differed from modern ones, being more arid.