Comparative Analysis of the conditions for the red tidies development at the Cretaceous–Paleogene boundary of the Stevens Klint and Zumaia sections

Abstract

The closest mass extinction to present occurred at the Cretaceous–Paleogene Boundary. The article presents the results of a geochemical study of the sections Stevens Klint (Denmark) and Zumaia (Spain). Authors built petrochemical modules (CIA) and indicators which demonstrate differences in the evolution of the environment at the K / T boundary. On the basis of the modern behaviour and development of dinoflagellates, an assumption was made about the possibility of the development of red tides as a chain of catastrophic events at the K / T boundary. It is shown that the conditions of southern latitudes demonstrated the best conditions for the development of red tides and the creation of anoxic zones. While in the northern regions, red tides could only be sporadic and could not be the cause of the biotic crisis that began in the aquatic environment.