Climatic changes in eastern Asia as indicated by fossil floras. II. Late cretaceous and Danian

Four Late Cretaceous phytoclimatic zones — subtropical, warm-temperature, temparature and boreal — are recognized in the Northern Hemisphere. Warm-temperature vegetation terminates at North Sakhalin and Vancouver Island. Floras of various phytoclimatic zones display parallel evolution in response to climatic changes, i.e., a temperature rise up to the Campanian interrupted by minor Coniacian cooling, and subsequent deterioration of climate culminating in the Late Danian. Cooling episodes were accompanied by expansions of dicotyledons with platanoid leaves, whereas the entire-margined leaf proportion increased during climatic optima. The floristic succession was also influenced by tectonic events, such as orogenic and volcanic activity which commenced in Late Cenomanian-Turonian times. Major replacements of ecological dominants occurred at the Maastrichtian/Danian and Early/Late Danian boundaries.