Abstract: There are several opinions on boundary dlassification between Cretaceous and Jurassice in hinterland of Junggar basin, which have caused the confusion in the stratigraphic correlation and the integrated exploration researches. The unconformity surface between the Cretaceous and the Jurassic is resulted from the second episode of Yanshan tectonic movement. There could be many litho-stratigraphic traps between them, so proper stratigraphie classification has infuenced the recognition of litho-stratigraphic traps directly. This paper presents the correlation and demonstration of several opinions on the boundary classfication based on much information about the character of biological combination, the character of lithology combination, the goologic model, the forward model, the seismic feature, etc, has established the rational program for the stratigraphie classification.

Key words: Junggar basin, Cretaceous, boundary classification, unconformity