Kimmeridgian–Volgian Palynological Assemblages of the Eganovo Section (Moscow Region) and Their Possible Application for Biostratigraphy, Correlation, and Facies Analysisстатья
Статья опубликована в журнале из списка Web of Science и/или Scopus
Аннотация:—The results of study of marine and terrestrial palynomorphs in the Lower Kimmeridgian and Middle-Upper Volgian in the Eganovo section (Moscow region) are presented. The section is well characterizedby ammonites providing a biostratigraphic control of the palynostratons. Beds with spores and pollen areidentified for the Volgian interval and beds with dinocysts are distinguished for the entire section. Certain taxaallow comparison of synchronous successions of dinocysts of the European part of Russia, Siberia, and Western Europe. By spores and pollen, a correlation is possible with coeval rocks of the northern Urals, WesternEurope, and Australia. The facies analysis of two palynological groups allowed reconstruction of features ofmarine algoflora and their interrelation with transgressive–regressive dynamics of the paleobasin, climaticfluctuations, and change in coastal landscapes. The comparative analysis of the lateral distribution of coevaldinocyst assemblages from the Eganovo section and other Boreal regions showed a significant similarity ofalgoflora of European Russia, the North Sea region, and Bulgaria in the Kimmeridgian, but the lateral differentiation of algoflora increased to the end of the Volgian. At the same time, the diversity of the dinocystassemblages in the European part of Russia remained high. It is suggested that this was caused by favorabletemperature and trophic conditions, which are interpreted using the results of facies analysis of terrestrial palynomorphs. The features of their taxonomic composition are typical of the Euro-Sinian paleogeographicarea with a subtropical climate. Gradual cooling in the second half of the Volgian was accompanied by recovery of small climatic maxima, which are also traced in Western Europe, Siberia and the northern Urals. Noperiod of aridization typical of the terminal Jurassic of Western Europe was revealed. Wet conditions led tothe formation of specific palynoflora with abundant gleicheniaceous ferns in the European part of Russia andadjacent territories of the Urals and margins of Western Siberia.