基金This paper is part of the project ＂Study on Cycles and Events and Their Relative Sedimentological Problems for the Mesoproterozoic Jixian System in the Yanshan Region＂ （Grant No. 40472065） financially supported by the National Natural Sciences Foundation of China, and is part of the project ＂Study on Lithofacies and Paleogeography from Meso- to Neoproterozoic in North China＂ financially supported by the China Petrochemical Corporation （Grant No. C0800-07-ZS-164）. The acknowledgements are made to Professor Yang Fengjie for their great help in the fieldwork and Professor Robert Scott for his detailed discussion. Acknowledgements are also made to Drs Mo Niya, Fu Ying, Zhang Huichang and Han Lin for their great help in the fieldwork. We also graciously thank Professor Gao Linzhi for his thoughtful criticism and constructive suggestions that helped to clarify and improve the manuscript. Finally, we remain fully responsible for any shortcomings in the material presented.