EARLY PALAEOZOIC SEDIMENTARY FACIES IN THE SHENGLI OIL PROVINCE,NORTH CHINA PLATFORM

The marine carbonate sediments were laid down during the Early Palaeozoic in the Shengli oil province as part of the North China platform.The sedimentary facies in the study area consist of clastic sedimentary facies series and carbonate sedimentary facies se-ries according to sedimentary rock types,and the Lower Palaeozoic sedimentary facies may be subdivided into four facies and nine subfacies in the light of sedimentary structures,di-agnostic minerals and fossil organism.The present paper gives a more detailed description of the characteristics of the above-mentioned sedimentary facies in different stages of the Early Palaeozoic.For instance,the sedimentary facies comprise supratidal to intertidal zones during the Mantouan and Xuzhuangian,subtidal shoal and open sea facies during the Zhangxian and Gushanian,intertidal and subtidal zones during the Changshanian and Early Ordovician,the alternation of the shallow-water supratidal and intertidal zones and deeper-water subtidal zone during the Middle Ordovician.The research in this study is believed to have important implications for the evaluation of the carbonate reservoirs and source rocks in the study area.