Paleobotanical study of a section of the Oligocene–Lower Miocene Maikop Group along the Belaya River above the city of Maikop, Ciscaucasia

Abstract

A stratotypical section of the Oligocene–Lower Miocene Maikop Group in the valley of the Belaya River above the city of Maikop was studied using a complex paleobotanical method. The hydrological regime of marine basin was specified, especially for the second half of the Early Oligocene, when the basin was brackish. Its desalination began prior to accumulation of the ostracod layers and continued until the beginning of the Late Oligocene. It was once interrupted by short-term ingression of seawater into the Paratethys in the Early Morozkina Balka time. The Karadzhalga and Septarian formations were formed at the end of the Oligocene and in the Early Miocene under frequent oscillations of climate and hydrological regime with accumulation of sediments within the Laba delta front. The complexes of plant microfossils, along with dominant recent marine organic-walled freshwater phytoplankton, contain algae, spores, pollen, and a huge amount of redeposited palynomorphs. They originated from areas of erosion and included Paleogene, Mesozoic, and, locally, Paleozoic taxa.