Abstract <p>Paleopedological studies were conducted on the territory of the Kostenkovsko-Borshchevsky raion. The K12 ancient human site is a reference section for regional studies of paleopedology, paleoecology, geological, and cultural sequences. K12 contains a complete series of cultural layers related to the first part of MIS-3 in the range of 53–42 thousand years BP. This study is a continuation of previously conducted work on the K1 site, located on the opposite side of the Pokrovsky Log balka. At the K12 excavation, 16 lithological layers were identified, differing in structure, composition, and properties. The material composition of the sediments is represented by chalk eluvium, which forms the sides of the balka, and loesslike loams of the watershed. Deposits with different proportions of chalk and loam were formed in the aqueous and aerial phases of sedimentation. In the excavation, about 5 m deep, three buried soils were found. The age of the lower one is about 50 thousand years BP. Cultural layers are confined to paleosols. Paleosols are an indicator of breaks in sedimentation. Four soil-sedimentary complexes were identified in the excavation. A description of the processes and the chronological sequence of their formation is given. The conducted research opens up new aspects in the study of buried soils of ravine–balka sedimentary complexes.</p>