Textures and micromorphology of the early Valdai pedosediments and their importance for the reconstruction of the natural conditions in the period of the first Post-Mikulino cooling (MIS 5d)

Pedosediments of the Mikulino interglacial paleosol contain information about the Early Valdai cooling. For the periglacial zone of the East European Plain, this period correlating with marine oxygen-isotope stage (MIS) 5d has not been separately distinguished in the known national stratigraphic schemes by the Committee on Stratigraphy and by Velichko with coauthors [4]. However, in the buried erosional landforms of the Mikulino interglacial, the deposits corresponding to this period reach considerable thickness (up to 5 m). They were examined in the key section of the Aleksandrov quarry (Kursk oblast). On the basis of the textural and micromorphological analyses of the Early Valdai pedosediments, the paleoenvironmental reconstruction of the first Early Valdai cooling was performed, and the major supergene processes (pedogenic, cryogenic, erosional, etc.) that shaped the pedosediments were characterized. Four stages of the development of local landscapes were distinguished, and a unidirectional trend for climatic cooling against the background of the complex pattern of climatic moistening in that period was established. Thus, a detailed pattern of the changes in the climate at the turn of the Mikulino interglacial period and the Early Valdai cooling was reconstructed.