Popiuk Y. Palaeogeographical conditions of low terraces formation in the Middle Dniester and Upper Prut areas (by mollusc fauna).

Based on geomorphological, stratigraphic and malacofaunistic study of Late Pleistocene sediments on low terraces of the Middle Dniester and Upper Prut areas, the taxonomic and ecological composition of malacofauna in these sediments, the biodiversity of the mollusc assemblages for cold and warm stages of Pleistocene, as well as the differences in the species composition of cold and warm stages, have been established. Reconstructions of paleoecological conditions have been performed, and a comparative analysis of the natural conditions of the Middle Dniester and Upper Prut valleys in the late Pleistocene has been carried out. The obtained results allowedus to substantiate the changes in the species composition of mollusc fauna as a reaction to short-term changes in landscape-climatic conditions during the Pleistocene. The necessity of considering microstratigraphy and facies variability of sediments to solve the problem of "mixed" mollusc associations is proved. The individual features of species and ecological composition of terrestrial Pleistocene mollusc associations, the dominance of individual taxa in them, are proposed for biostratigraphic subdivision of sediments.