This thesis paper focuses on the age and correlation of regional paleogeographic events of the Pleistocene epoch in Ukraine, based on a combination of the microteriological method and the method of paleogeographic reconstruction.
The microteriological method, the study of dental remains of small mammals, used in the stratigraphy and paleogeography of the Pleistocene of Ukraine. This method has prospects for further development. This is facilitated by the involvement of new and the revision of old paleontological materials, new data on determining the appearance and disappearance of species during the Quaternary period, using improved biostratigraphic schemes for small mammals.
Our scientific idea: to explore the possibilities of the method of paleogeographic reconstructions for dating and correlating regional paleogeographic events, to involve this method on a par with microteriological method. For problems of dating sedimentary rocks and correlating of local, regional and interregional scales.
We can consider this thesis paper in the context an important branch of research in modern stratigraphy – event stratigraphy. The thesis research included 39 outcrops, they contain deposits of loess-soil, alluvial, marine, and glacial formations.
Personally reviewed 134 units. According to previous researchers, the total number of remains at these sites was 7,220 specimens. The largest and most informative group is rodents, which contains 69 species taxa. The most attention was paid to the subfamily voles (Arvicolinae) – these are mouse-like rodents, 58 species.
In my research for dissecting Quaternary sediments, apart from microteriological method added paleogeographic reconstructions. The complex combination of these methods allowed for a detailed analysis and correlation of Pleistocene sediments of Ukraine. Thanks to these studies, was clarified/changed/established the stratigraphic position of a number of Pleistocene localities in Ukraine.
Outcrops of the alluvial formation of the Mykhailivska and Kolkotovska floodplain terraces of the Dniester, as well as the Mountain Terrace of the Danube, reflect a single stage of sedimentation during the Early Neopleistocene (mr-tl), which is confirmed by small mammals of these areas. Geological structure of the entire thickness of the Nagirne terrace and stages of evolution of small mammal fauna.
We applied a complex paleontological-formation approach for the first time. And found out that relatively isochronous microtheriofaunas of the regional, or subordinate to him, stratigraphic subdivision of sediments of different formations, differ in systematic composition, odontometry, and paleogeographic features. This is due to sedimentation conditions, and also with the processes of macro- and microevolution in individual taxonomic groups.
In this thesis work we proposes the hypothesis of «microteriological successional series», which record changes in the natural environment before and after the formation of glacial complex deposits. «Microteriological successional series» allocated only for the Northern region within the distribution of the Don and Dnieper glaciers. A characteristic feature of these series is the presence of lemming faunas only in the sub-morainic deposits of the Don glaciation, and in the overmoraine sediments of the Dnieper glacial.
Practical value of research work: the results of morphometric research of fossil voles teeth can be used in the taxonomy of the group, clarification and construction of phylogenetic lines, determining trends in the evolutionary development of rodents. The results of biostratigraphic studies, correlation constructions, and paleogeographic reconstructions can be used to detail correlation stratigraphic schemes of the Pleistocene and construct improved paleogeographic maps. The materials of the work can be used for educational purposes, for example, for the courses «Fundamentals of the biostratigraphic method», «Quaternary Geology», «Paleozoology», «Paleogeography».
Key words: small mammals, voles, paleontology, heterogeneous formations, Pleistocene, stratigraphy, biostratigraphy, paleogeography, correlation.
