Biostratigraphical characteristics of the Holocene deposits of the Southern Urals

This paper is a synthesis of previously published and unpublished materials dealing with the stratigraphy of the Holocene deposits of the Southern Uralian region (easternmost part of Europe). Results of the mammalian, amphibian, reptilian, malacological, and palynological investigations as well as radiocarbon data provide the basis for stratigraphical subdivision and reconstruction of the palaeoenvironments. The Holocene is represented by the Agidel Horizon with three subhorizons. The Holocene deposits form the high and lower flood plain terraces and the unconsolidated deposits in the caves. The vegetation development is based on Betula-coniferous forests at the beginning of this interval, which were replaced by Pinus-Picea forests with broad-leaved trees admixture (Early Holocene). At the beginning of the Middle Holocene birches decreased and the broadleaved trees and Picea increased in the forest compositions. The climate was warmer and more humid than the modern one. During the Late Holocene the type of vegetation was close to the modern one. Picea-Pinus-birch-tree forest was growing in the northern part of the Southern Fore-Urals with broad-leaved trees in the southern part. The percentage of open woodlands with Artemisia-Chenopodiaceae-herbage associations increased towards the end of that time. The mollusc fauna is represented by terrestrial and freshwater species. The variety and quantity of the terrestrial species increased compared with the Late Neopleistocene. The main part of the modern amphibian fauna of Southern Urals was formed during the Early Holocene. Modern amphibian fauna developed at the end of the Late Holocene and is represented by forest species. The modern fauna of reptiles of the Southern Urals formed at the end of the Late Holocene when steppe species disappeared. Nowadays, steppe biotopes exist in the southern part of this area. In the Southern Urals, the Early Holocene small mammal steppe biotopes were replaced by the modern forest biotopes. In the Trans-Urals the faunas were steppe species throughout the period. The Holocene large mammal fauna was characterized by the transition from the Mammoth to the Holocene complex when Late Pleistocene species disappeared during the Early Holocene.