Subsidence of Buried Soils in Cyclic Loess Sequences of the Northern Eurasia

Abstract

We present spatial distribution of loess soils sequences on the territory of East European and Central Asian regions considering the vertical structure of collapsible loess sequences. Data about loess key sections of Northern Eurasia (Moldova, Ukraine, Ciscaucasia, Central Asia) are cited. We also present composition, structure and properties of buried soils from cyclic loess sequences of East European and Central Asian regions that are characterized by grain size distribution, organic content, natural density etc. Correlation of assessed collapse from sampling with depth of occurrence, natural moisture content and porosity are revealed. Maximal subsidence was observed under the natural humidity 5–15 %. Buried soils composed of loess-like heavy sandy loams and loess-like light and average loams possess the greatest value of subsidence. Only soils with porosity over than 40 % are subsiding. Alteration of subsidence in the section of buried soils is considered. Two main types of subsidence distribution can be distinguished on the basis of these limited data.