RUSAVA-2, A NEW LOCALITY OF MID-PLEISTOCENE FAUNA AND PALYNOFLORA IN UKRAINE: GEOLOGY, PALAEONTOLOGY, PALAEOGEOGRAPHY AND RELATIVE GEOCHRONOLOGY

Abstract

This paper reports the results of field geological studies of Rusava-2 section recently discovered in Vinnytsia Region and an examination of the fossil fauna and palynoflora from the locality to provide a deeper and integrated characterisation of the Pleistocene deposits of the Middle Dniester area of Ukraine. Ten taxa of mammals were identified in the alluvial series of the terrace: Equus (Equus) mosbachensis, Bison sp., Cervus sp., Vulpes cf. vulpes, Ochotona ex gr. pusilla, Prolagurus cf. posterius, Arvicola mosbachensis, Mimomys sp., Microtus sp., Allocricetus bursae. The invertebrate fossils represent the ostracod Pseudocandona compressa, 11 species and subspecies of Pleistocene freshwater molluscs, and also include redeposited gastropod shells of the Sarmatian age. A palaeogeographic reconstruction of the development of the terrace complex deposits was made and a relative geological age of the alluvial sediments of the terrace was estimated. The numbering of the Pleistocene terraces of Ukrainian rivers was discussed and the chronocorrelative terraces were proposed to be described as geological bodies with paleontological-chronostratigraphic characteristics. The conducted palynological analysis of the subaerial sediment cover of the terrace suggests a change in vegetation from the meadow-steppe type through coniferous-birch communities to coniferous forests with a small admixture of broadleaved trees. The biostratigraphic analysis indicates the correlation of the subaqueous sediments of the Rusava-2 section with the early Middle Neopleistocene deposits and with the above-floodplain Zavadivka-Dnieper terraces containing the fauna of the Babel therioassociation and flora of the Zavadivka thermochrone.