New Data on the Chronostratigraphy of the Upper Pleistocene Loess–Soil Series in Southwestern Siberia

We have analyzed the modern status of the chronostratigraphic differentiation of the loess–paleosoil series in southwestern Siberia and the results of luminescence dating of the reference section of the Altai low mountains near the settlement of Krasnogorskoe. A complete series of the Middle and the Late Pleistocene levels of paleosoil formation is distinguished. Six new dates were obtained for the section by optically stimulated luminescence (OSL) and infrared stimulated luminescence (IRSL), and two samples were measured simultaneously, using quartz and feldspar, to control the light exposure and the reliability of the absolute age determined. The results obtained indicate the formation of the lower Berdsk paleosoil during the last interglacial period, which corresponds to Marine isotopic stage (MIS) 5e, and two dates of the underlying loess (127 and 149 ka BP) confirm that the age of this strata correlates with MIS 6. The age of the overlying Iskitimsk pedocomplex and of the horizon of Yeltsovsk loess is also substantiated by four OSL dates (48–39 and 39–25 ka BP). The final chronology confirms the previously elaborated chronostratigraphic scheme of the loess–paleosoil series in southwestern Siberia, which is based on a detailed morphological characteristic of paleosoils.