Stages of Development of the Ryshkovo Pedolithocomplex as an Alternation of Favorable and Extreme Conditions in the Mikulino Interglacial (MIS-5e)

Eurasian Soil Science. 2024. Vol. 57. No. 1. P. 114–127.

Sycheva S. A., Pushkina P. R., Golyeva A. A., Khokhlova O. S., T. M. Gorbacheva, Kovda I. V.

In 2011, in the Aleksandrov quarry (Kursk oblast, Russia), the Ryshkovo pedolithocomplex of the
Mikulino (Eemian) Interglacial (MIS-5e) was studied. It includes three to four soil profiles separated by
humified pedosediments. The lower soil is an eroded gray forest soil, the two middle soils ones are meadow
soils at the bottom of the ravine and a soddy-podzolic soil on the paleoslope, and the upper soil is an underdeveloped
soil with elements of forest pedogenesis. Morphological, physicochemical, and microbiomorphic
studies of the pedolithocomplexes on the slope and in the bottom of the buried coastal ravine filled with colluvial
and alluvial–colluvial sediments made it possible to reconstruct at least three pedogenic and four morpholithogenic
stages in MIS-5e, which significantly detailed the event history of the interglacial. In the profile
of the Ryshkovo pedolithocomplex, the buried humus horizon of the lower gray forest soil is clearly visible
reflecting warmer climatic conditions of the first half of the last completed interglacial in comparison with its
second half. Soil formation in trans-accumulative landscapes was repeatedly interrupted by erosion–accumulation
processes, which reflects the instability (rhythmicity) of the climatic situation during the Mikulino
interglacial and correlates well with detailed records from other geological archives.

Keywords: stages of development, paleosol, slope, ravine, interglacial MIS-5e, phytoliths, Aleksandrov quarry