Die Entwicklung kalkiger Dinoflagellaten im Südatlantik seit der höheren Oberkereide.

Abstract

Fossil calcareous dinoflagellate associations differ significantly from those in modem oceans in a number of aspects, including the abundance of taxa, diversity and wall type. The exact nature as well as the causes and effects of this association change are still obscure. In order to shed light on the evolutionary history of calcareous dinoflagellate associations, this study focuses on the long-term temporal and spatial distribution patterns in the South Atlantic Ocean for the Maastrichtian to Miocene time-interval. The study thereby not only addresses the effect of the biotic crisis at the Cretaceous-Tertiary boundary, but also concentrates on the influence of Cenozoic climate evolution. Using scanning electron microscopy and polarisation microscopy, about 6,500 calcareous dinoflagellate specimens have been examined in sediments originating from three DSDP and ODP cores (Holes 356, 357 and 689B). The broad time-interval led to a redefinition of biogeographic and stratigraphic ranges of numerous taxa.