Taxonomical Diversity of Cenomanian-Turonian Dinocyst in the Northern Hemisphere: Some Aspects of Paleobiogeography and Paleoclimatology

Abstract

Taxonomic typification of dinocyst assemblages was carried out on the basis of a qualitative and quantitative assessment of their generic composition for the Northern Hemisphere in the Cenomanian-Turonian time in order to identify correlation taxa. Three types of dinocyst assemblages were identified in the Cenomanian. Cenomanian dinocyst assemblages are poorly differentiated; a large number of cosmopolitan genera was identified, which is in good agreement with paleobotanical data on a very warm, humid climate. Three types of dinocyst assemblages were established for the Turonian age. The number of cosmopolitan genera of dinocysts decreases, and species endemism sharply increases in individual Turonian basins. The differentiation of assemblages increases and their correlation potential decreases. However, the identified common genera and species of dinocysts in different types of assemblages provide the possibility of interregional correlation of Upper Cretaceous deposits at the stage, substage, and, at some sections, even more detailed levels in different climatic zones.