Palynological analysis of Lower Cretaceous (Berriasian-Barremian) sections from North Siberia allows definition of detailed dinocyst and sporepollen zonations, which are calibrated against the established ammonite biostratigraphic schemes of Siberia. Most of the boundaries of the palynological zones are reliable correlative markers, which also can be recognized elsewhere in East and West Siberia (the spore-pollen zonation) and in NW Europe, Canada and Siberia (the dinocyst zonation). Changes in the microphytoplankton associations reflect both trends related to the dynamic evolution of the Siberian palaeobasin and trends of the dinocyst evolution. Results from the present study suggest that the diversity and the abundance of the Siberian microphytoplankton associations to a large extent were determined by sea water temperature and nutrients.
Lower Cretaceous palynostratigraphy and dinoflagellate cyst palaeoecology in the Siberian palaeobasin