New Palynological Data from the Middle Eocene Deposits of the Kheu Reference Section (Kabardino-Balkaria, North Caucasus)

摘要

The results of palynological study of the middle-upper Eocene interval of the Kheu reference section are presented. The dinocyst zones such as Enneadocystaarcuata, Costacystabucina, Enneadocystapectiniformis, Rhombodiniumdraco, Reticulatosphaeraactinocoronata, and Talladinium? angulosum were recognized in the studied part of the section. Based on the first order calibrations with calcareous nannoplankton, their stratigraphic boundaries are established as well as the lowermost occurrences of stratigraphically important species are refined. New microplankton data suggest the early Lutetian age of the uppermost Cherkessk and Keresta formations; the Kuma Formation is dated by late Lutetian-earliest Priabonian, while the lowermost Belaya Glina Formation corresponds to the Priabonian. Analysis of ratios of marine and terrestrial palynomorphs in the Kheu section permits to interpret the paleoenvironments during the Lutetian-Priabonian in the studied part of the eastern Peri-Tethys.