ИСТИНА

For the Cretaceous reconstructions we suggest to use the extinction of planktonic foraminifers (PF) which lived in the water column like their modern representatives and were controlled by similar environmental factors: water temperature, water-mass structure, amount of nutrients, and stability instability of oceanographic conditions.The climate during the Cretaceous had been globally warm, although from low to high latitudes it was less contrasted than in modern oceans. During the important Cretaceous radiations PF increased in size and acquired very special morphologies. PF evolved rapidly in some intervals (punctualism), slower in others (gradualism), allowing to construct a biostratigraphic scale at high resolution especially at low latitudes (Crimea-Caucasus area). Biostratigraphic scales for high latitudes have very low resolution (Russian Platform).