Periglacial structures in the middle Desna River basin and their stratigraphic and palaeogeographic significance
DOI:
https://doi.org/10.26485/BP/1958/6/5Keywords:
frost wedges, cryoturbations, periglacial structures versus climate featuresAbstract
In the middle Desna River basin, between Bryansk and Novgorod-Seversky, periglacial structures occur at several levels corresponding to different glacial periods. The advance of the Dnieper glaciation is associated with disturbances in the basal parts of Quaternary deposits and partly in the underlying rocks. The maximum stage of this glaciation left permafrost structures in the lower horizons of a fossil soil. Loess-like silty sands originate from the Valdai glaciation period. Based on the analysis of periglacial structures, two series of these deposits have been distinguished. The lower series corresponds to cold and dry climatic conditions during the advance and maximum of glaciation, whereas the upper series represents the period of the retreat of the Valdai glacier. The author believes that periglacial structures may serve as an important criterion for drawing stratigraphic and palaeogeographic conclusions.
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