Early Permian Sporo-Pollen Assemblages in Dongtan,Yanzhou, Shandong Province

Palynological samples from the complementary drill 33 were analyzed in the Dongtan coalfield of Yanzhou,Shandong Province.There are abundant sporo-pollen fossils from the Taiyuan Formation to the Lower Shihezi Formation,and 55 genera and 155 species of sporo-pollen fossils have been found.According to the vertical changes of the components and contents of sporo-pollen fossils,the sporopollen may be distinguished into 3 assemblages as follows(from upper to lower):Ⅲ.Florinites-Punctatisporites assemblage(428.36～369.10 m),Ⅱ.Punctatisporites-Sinulatisporites assemblage(543.43～496.95 m),Ⅰ.Thymospora pseudothiessenii-T.thiessenii assemblage(589.20～550 m).Compared with the assemblages in some other areas of northern and southern China,and referring the international Carboniferous-Permian boundary,which is moved to the bottom of the Pseudoschwagerina zone,the geological age of the assemblages in Dongtan,Yanzhou should be early Early Permian(assemblages Ⅰ),middle Early Permian(assemblage Ⅱ)and late Early Permian(assemblage Ⅲ).Finally,we discuss the paleoclimate change according to the sequence stratigraphical analysis.