Relations Between Synsedimentary Tectonic Activity and Sedimentary Framework of Dongying Formation in Nanpu Sag

Under the guidance of tectono-sequence stratigraphy and the association analysis of tectonic and sequence framework,the sedimentary filling patterns,process,and controlling factors of Dongying Formation in Nanpu Sag are comprehensively studied.Through the analysis on subsidence history and regional tectonic evolution characteristics,the Paleogene can be divided into four secondary tectonic episodes.Faults are very developed within Nanpu Sag.It is found that the synsedimentary faults and their temporal and spatial configuration have significant control on the intra-sag structures,types and distribution of sedimentary system.The boundary faults control the variation of accommodation space and paleogeomorphology of some local tectonic zones,which result in forming different sediments distribution features.Gaoliu Fault is the most important secondary fault in Nanpu Sag.It starts during the Es1 depositional period,and its activity gradually reaches the strongest in Dongying Formation.During the deposition period of Dongying Formation,Gaoliu Fault divides sag into two parts,the southern and northern parts.After its development,the Gaoliu Area becomes an isolated lacustrine basin for the intensive tilting process of the fault during the sedimentary period of Ed3,which directly influences the sedimentation in Gaoliu Area.Based on the faults combination styles of Dongying Formation in Nanpu Sag,four types of tectonic slope break are identified,which are faulted scarp type,faulted slope type,concordant and antithetic faulted terrace types.These tectonic slope breaks provide a favorable guidance to the study on the controlling of synsedimentary faults on sedimentary framework in Dongying Formation,Nanpu Sag.