Sedimentary facies in the lower part of the third member of the Palaeogene Shahejie Formation in the Shulu depression,Hebei

The present paper deals with the sedimentary features of the lower part of the third member of the Palaeogene Shahejie Formation in the Shulu depression,Hebei on the basis of sedimentary facies and sedimentary structures,plant remains and geochemical signatures.The detailed study of the sedimentary microfacies has disclosed that the thick massive sandstone and conglomerate are dominantly composed of matrix-poor debris flow deposits with rare turbidity current deposits and grain-flow deposits.The marl mainly consists of the mixed deposits,which may be subdivided into the interbedded mixed deposits,structural mixed deposits and intercalated mixed deposits.In general,the study area displays,as indicated by the planar distribution of the sedimentary facies in the study area,the semi-deep lake and deep-lake depositional systems in which the debris flow deposits and mixed deposits are accentuated.