The Relationship Between Magmatic Activity And Tectonic Structure Of Lufeng 13 Structural Belt In Pearl River Mouth Basin

Lufeng 13 Structural Belt is one of the highest exploration area and rich in oil and gas which belongs to Lufeng Sag.Some predecessors have already did some researches about igneous rock in Pearl River Mouth Basin,but not have detailed igneous rock's researches in Lufeng area.The multiple episode of magmatism affects the attitude and physical property of early strata.Meanwhile,studying in lithology of basement is necessary to ensure the source of sediment.The paper based on the recognition of magmatic rocks and lithology,analyses the distribution of the basal lithology,the episode of magmatic activity and its relationship with tectonic movement.Thus provides theoretical support for the study about sedimentary process,formation of reservoir,accumulation of oil and gas.By using drilling,logging and seismic data,analysing petrological,logging curve and seismology features,it becomes possible to know the composition of basement.The basement is composed of sedimentary rocks and magmatic rocks.The magmatic rocks include granite,basalt and andesite.First,identify the body of magmatic rock and its distribution range,and discuss the contact relationship between magmatic rock and other strata,combined with K-Ar data in the same time,then to assure the episode of magmatic activity.Magmatic activity in the study area can be divided into five periods: The initial of rift stage,intensive rift stage,weak rift stage,fault sag stage,depression stage.The distribution of magmatic rocks in the study area is affected by regional tectonic movement and fault characteristics.Volcanic rocks follow the fault in the NWW-SEE or nearly EW direction.Intrusion rock follow the fault or fault zone in NWW direction in the west of the area,and in the N EE to EW in central or eastern area.There are some local unconformity surface s in the study area,according to the analysis,the magmatic activity especially magmatic diapirism are the necessary factors for the formation of regional unconformity surfaces.