A Study on the Boundary Age between Jurassic and Cretaceous
Abstract:It is agreed that the boundary level of the Jurassic Cretaceous is put in between the Dabeigou Formation (narrowsense) and Dadianzi Formation. The ages of the volcanic rocks from the Jehol(Rehe) Group and its underlying formations in Luanping County of Hebei those have bee measured by means of 40 Ar/ 39 Ar dating .The age of Jurassic-Cretaceous boundary is aroud 140±1 Ma which is recommended in this paper.