Biogeography and Paleogeography of Taxonomic Diversity of Coniacian-Santonian Dinocysts of the Northern Hemisphere
N.K. Lebedeva
Trofimuk Institute of Petroleum Geology and Geophysics, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia
Keywords: Dinoflagellate cysts, Coniacian, Santonian, biogeography, paleogeography, correlation
Abstract
Dinocyst assemblages are subjected to taxonomic typification based on a qualitative and quantitative assessment of their generic composition for the Northern Hemisphere during the Coniacian-Santonian time in order to identify correlation taxa. The typification is carried out using a cluster analysis according to the Jacquard calculation model (BioDiversity Professional, 1997). Three types of dinocyst assemblages have been identified in the Coniacian. As compared to the Turonian, the relatively cold-water West Siberian basin is characterized by a decrease in the number of cosmopolitan taxa and an increase in species endemism. The only taxa identified at present are those allowing for intrabasin correlations. Three types of dinocyst assemblages have also been established for the Santonian. Free interbasin connections in the Northern Hemisphere contribute to the equalization of the generic composition between the three identified types and to the identification of characteristic taxa that allow for interregional correlation.
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