A discussion on Jurassic and Cretaceous boundary based on the SHRIMP zircon U-Pb dating of Mesozoic holitype section in Luanping basin

This paper is the record of a field investigation of Mesozoic strata in Luanping County, Hebei Province, which was organized by the Commission on Stratigraphy of China. A tuff sample was collected in the Dabeigou Formation at the top of the Jurassic strata. According to the chronostratigraphic dating, the authors think over the terrestrial Jurassic/Cretaceous boundary based on the tuff zircon dating. The terrestrial Jurassic and Cretaceous strata are well developed in Luanping County, Hebei Province. Various terrestrial fossils are very abundant with a large amount of tuffeous rocks. It is an ideal province for the study of Jurassic/Cretaceous boundary and the Dabeigou Formation and Dadianzi Formation based comprehensively on lithogical stratigraphy, biostratigraphy, chronostratigraphy and magnetostratigraphy. According to the chronostratigraphy, the boundary age of Jurassic/Cretaceous tends to favor the era of 130Ma. This paper reports a SHRIMP U-Pb age of 129.9±1.1Ma for tuff of the holitype section of the Dabeigou Formation from Yushuxia Village, Luanping County.