XVI International Botanical Congess

The investigation of taxonomical and ecological composition and foliar physiognomy of fossil floras allow to estimate the Maastrichtian climates in the northeastern Eurasia and the northwestern North America from 35?N up to 70?N. Fossil plant evidence indicate that climate during the Maastrichtian was warm temperate at high and middle latitudes and subtropical south of 40?N. Precipitation was relatively high and evenly distributed over the year. Annual range of temperatures was similar to that of modern maritime climates and latitudinal gradient was significantly lower than at present. At high latitudes cold-month mean temperatures amounted 3-4?C and probably never dropped below 0?C for a long time. Evidence coming from oxygen-isotope data are in good agreement with climate predictions derived from plant physiognomy. It seems, that winter temperatures at polar regions were so high due to the heating of these areas by warm high latitude upwellings.