Paleoecological Data of the Sarmatian Basin on Microfauna of East Georgia

摘要

Biocenosis of the Early Satmatian (Volhynian) basin is homogenous. Microfauna is characterized by saline forms. Due to the developed conditions the amount of stenohaline species reduced or disappeared. In the Middle Sarmatian (Bessarabian) the microfauna is distinguished in its diversity. Endemic species appeared. Desalination and freshening of the Late Bessarabian basin led to the sharp impoverishment or extinction of microfauna. In stratigraphic sections, compiled in Eastern Georgia (the rivers Aragvi, Ksani, Lekhura, Noriostskali), the species of the following genera are recorded: foraminifera - Quinqueloculina, Nubecularia, Wiesnerella, Dogielina, Nonion, Porosononion, Elphidium, Globigerina; ostracods - Pontocypris, Leptocythere, Loxoconcha, Aurila, Cyprideis. In the complex of ostracods with the exception of the species that passed from the Konkian typical Sarmatian species occur. They considerably differ from the Mediterranean ones. But in the complex of foraminifera the Mediterranean forms are established. In the Upper Sarmatian (Khersonian) of Eastern Georgia thick mute continental sediments are recorded. Late Sarmatian marine conditions are preserved in the vicinity of the river Iorispiri. In Georgia in the Late Sarmatian due to short term transgression the connection with the norm salinity seas restored and in marine sediments the ostracods of atypical Sarmatian appearance occured - Leptocythere maeotica (Suzin) and Xestoleberis maeotica (Suzin).