Новые данные о стратиграфической значимости разреза «Черемошник» (Ярославская область)

Вестник Московского университета. Серия 5: География. 2022. № 4. С. 88–100.

Шеремецкая Е. Д., Каревская И. А., Самусь А. В., Гаранкина Е. В., Шоркунов И. Г.

For several decades the northeastern slope of the Borisoglebsk Upland has been a focal point for natural scientist interested in geochronology and Quaternary environmental reconstructions. A key reference section of the Upper Volga River region is a set of geological cores, exposures and excavations on the side slopes of the Puzhbol Gully system. The ORV section (Eastern Cheremoshnik Gully) was studied in detail applying the comprehensive analytical approach. We revealed an intermittent geological record of local transformations in the exposed sequence as follows: unstable infilling of a lacustrine depression by mineral and mineral-biogenic sediment during the Mikulin thermoxeric stage; biogenic and mineral-biogenic accumulation in waterlogged areas during the transition to subaerial deposition under periglacial environment of an initial phase of the Early Glacial; discrete erosion and accumulation with associated slope processes during Pleniglacial; and just an episode of colluvial deposition attributed to a cold Holocene stage. Hiatuses in the paleogeographic record were identified for several periods of different duration, at least for the Mikulino thermohygrotic interglacial stage and for significant intervals of the Late Glacial and the Holocene, mainly because of the occasional activation of erosion processes. Stratigraphic discordances exposed in the ORV section have shown its deficiency as a reference one for the reconstruction of the Late Pleistocene and Holocene environmental history of the region. Nevertheless, we can use fractional particle size distribution of the layers formed by sedimentation of lacustrine depressions and erosion cuts as a sensitive indicator of the local Late Pleistocene lithodynamics.

Keywords: Голоцен, late Pleistocene, Holocene, спорово-пыльцевой анализ, гранулометрический анализ, Borisoglebsk Upland, grain size analysis, palynological analysis, Борисоглебская возвышенность, поздний плейстоцен