摘要
Cyclostratigraphic analysis was undertaken with several different spectral analysis methods on the Hanjiang Formation of Langhian age (Middle Miocene) in the Pearl River Mouth Basin of South China Sea,which consists of deltaic siliciclastic and neritic shelf carbonate rhythmic alternations.Within biochronological constraint,a high-resolution astronomical time scale was constructed.The results show that the Hanjiang Formation cycles are controlled by variation of the earth’s orbital period.The astronomically tuned time scale can be used to calculate astronomical ages for geological events and bioevents recognized throughout the period,and the results are only slightly different from earlier estimates in South China Sea.