부산대학교 도서관

Drilling recovered the upper part (23 m) of the upland loess–paleosol series (LPS) on the right bank of the Kuma River near the Otkaznoe Settlement. Description of cores and laboratory analyses made it possible to carry out lithostratigraphic subdivision of the loess sequence in the summary column. Four paleosol units separated by loess horizons are identified. The two lower contiguous paleosols are defined well in the cores by their dark brown color and high values of magnetic susceptibility. The other two paleosols are weakly expressed and identified mainly by variations in the mechanical composition and contents of organic matter and carbonates. Analysis of 13 luminescence dates obtained in two different laboratories (four dates at Karpinsky Russian Research Geological Institute (VSEGEI), St. Petersburg, Russia; nine dates at Leibniz Institute for Applied Geophysics (LIAG), Hannover, Germany) shows that the LPS belongs to the Late Pleistocene and Holocene. Based on the dates, three (two Bayesian and one linear) depth-age models were constructed. The linear model is in better agreement with the stratigraphic sequence and the cross-regional loess correlation. The age of boundaries of the stratigraphic units was calculated, and a preliminary correlation with the marine oxygen isotope stages (MIS) was carried out: soil S0—MIS 1; loess L1LL1—MIS 2; paleosol L1SS1—MIS 3; loess L1LL2—MIS 4; paleosol S1SS1—MIS 5a; loess S1LL1—MIS 5b; paleosol S1SS2—MIS 5c; loess S1LL2—MIS 5d; and paleosol S1SS3—MIS 5e. Calculations of the sedimentation rate yielded the following results: minimum growth rate of the loess sequence in the Holocene (9 cm/ka) and Mikulino time (10 cm/ka); maximum rate, at the end of the middle–beginning of the late Valdaian (79 cm/ka). Pedostratigraphy and compositional variations give grounds for correlating the summary column with the core of reference Borehole-1 drilled in the Otkaznoe Settlement in 1986. [ABSTRACT FROM AUTHOR]