Quaternary deposits and biostratigraphy in caves and grottoes located in the Southern Urals (Russia)

摘要

Investigations of the unconsolidated Upper Pleistocene - Holocene cave deposits of the Southern Urals resulted in detailed biostratigraphical and palaeoenvironmental data. Landscapes of this area have a mosaic character. The forests have regional features developed at the transition of Eastern European broadleaved-dark-coniferous taiga and the Southern-Uralian light coniferous forests. The modern mountain mixed forests appeared during the end of the Holocene. The forest-steppes were widespread during Late Neopleistocene - Holocene. The forest vegetation existed during the warm periods (Tabulda, Middle-Late Holocene) and areas covered by forest were reduced during the cold intervals (Kudashevo, Early Holocene). However, refugia of broad-leaved flora existed in the territory of the Southern Urals even during coldest periods. The Late Pleistocene and Holocene mollusc species are Holarctic species that occur in forest-steppe, forest and intrazonal (river banks) ecological biotopes. The Late Pleistocene and Holocene amphibian associations found in caves are characterized by species that prefer forest biotopes. The reptile faunas contain species which inhabited open areas. The Pleistocene and Holocene fish fauna is a characteristic freshwater fauna occurring in a temperate zone: all species currently inhabit the European rivers. The Pleistocene and Holocene avifaunas include species that occur in the modern ornithological faunas of Northern Asia, Central and Northern Europe. The Late Pleistocene fauna was dominated by species that inhabited open and semi-open landscapes whereas, during the Holocene, species that preferred closed biotopes dominated the bird fauna. During the Late Pleistocene and Early Holocene disharmonious small-mammal faunas existed in the central and northern parts of the Southern Urals. These faunas included steppe and semi-desert species; lemmings are rare. In the southern part of the Southern Urals and in the Trans-Urals lemmings are absent. Starting from the Middle Holocene there is a gradual change of small-mammal communities. In the Southern Urals forest species replace the predominance of steppe species, and only in the Trans-Urals the steppe small mammal fauna preserved. The modern small-mammal faunal community appeared in the latitudinal part of the Belaya River valley at the end of the Late Holocene. There were relatively little changes in the Southern Urals large mammal fauna at the end of the Late Neopleistocene - beginning of Holocene. The large mammal fauna consisted of eurybiotic species and species that inhabit open landscapes. Species that prefer forest landscapes appeared at the end of the Early Holocene - beginning of the Middle Holocene. Modern large mammal species appeared during the second half of the Late Holocene.