Palynological assemblages from the Tuchengzi and Dabeigou formations in the Luanping Basin at Sanchazi Section, Northern Hebei Province and their implications
Article
Figures
Metrics
Preview PDF
Reference
Related
Cited by
Materials
Abstract:
The Tuchengzi and Dabeigou formations of the Hebei and Liaoning Provinces are of great significance for the Jurassic–Cretaceous stratigraphic division and correlation in northern China. However, the geological age of the two formations is still controversial, and only preliminary researches have been done on the palynostratigraphy. In this paper, moderately diverse pollen and spores are recovered from the Tuchengzi and Dabeigou formations at Sanchazi, Jingshang Village, Luanping County, northern Hebei Province, which comprise 50 genera and 28 species together with some indeterminate species as well. The palynoassemblage of the Tuchengzi Formation, namely Classopollis–Cooksonites–Ephedripites assemblage, is characterized by the predominance of Classopollis and considered to be Berriasian in age (Early Cretaceous) by the occurrence of Cooksonites variabilis、Crybelosporites punctatus and Ephedripites (E.). The Bisaccates–Foraminisporis assemblage recovered from the Dabeigou Formation is dominated by gymnospermous pollen and is evidenced of a middle–late Valanginian age by the occurrence of such age-diagnostic elements as Crybelosporites punctatus, Ephedripites (E.) crassistriatus, Foraminisporis wonthaggiensis, Jiaohepollis and Rugubivesiculites spherisaccatus. The present work uncovers an Early Cretaceous palynoflora from the top of the First Member of the Tuchengzi Formation for the first time, implying that the Jurassic–Cretaceous boundary in northern China lies within the First Member of the Tuchengzi Formation. Our research also shows the Bisaccates–Foraminisporis assemblage of the Dabeigou Formation in the Luanping Basin, northern Hebei Province is correlative to that from the top of the Third Member of the Tuchengzi Formation and the lower part of the Yixian Formation in the Jinlingsi–Yangshan Basin, western Liaoning Province, which means an equivalency of these strata.
