徽成盆地东河群孢粉化石的发现及其意义

Discovery of sporo pollen fossils from the Donghe Group of the Huicheng Basin and their stratigraphic significance

对甘肃南部徽成盆地东河群进行了孢粉研究，在上部的化垭组首次发现了一些孢粉化石。孢粉组合以ＣｉｃａｔｒｉｃｏｓｉｓｐｏｒｉｔｅｓＨｓｕｉｓｐｏｒｉｔｅｓＣｌａｓｏｐｏｌｉｓ为代表，蕨类植物孢子占明显优势，以海金砂科、水龙骨科和卷柏科为主；裸子植物花粉以掌鳞杉科最常见，还有松科及麻黄科花粉。经孢粉组合特征和属种地史分布对比分析，认为化垭组的地质时代属早白垩世，可能为早白垩世中期。

The upper layer of the Donghe Group in the Huicheng Basin of southern Gansu is the Huaya Formation, where some sporo pollen fossils were found for the first time. The Cicatricosisporites Hsuisporites Classopollis Assemblage was established. It is characterized by the evident dominance of pteridophyte spores, and gymnospermous pollen is the next. The pteridophytes include mainly Lygodiaceae, Polypodiaceae and Selaginellaceae. In the gymnosperms, the Cheirolepidiaceae is predominant, and there are also Pinaceae and Ephedraceae. Based on the analysis of some important genera and species in the assemblage and comparing them with the known assemblages in various districts, the writer considered the Huaya Formation to be Early Cretaceous in age, probably the middle Early Cretaceous.