Geological-geophysical Study Based On Gravity Magnetic Seismic Profile In South China Sea

The South China Sea is located at the convergence center of the Eurasian Plate,the Pacific Plate and the Indo-Australian Plate.It is the edge sea formed by the movement of these three plates and the expansion of the seabed.Cenozoic seafloor expansion in the South China Sea basin is an important part of the study of tectonic evolution in the South China Sea,recording important information on the evolution of a large number of continental margins to regional geological formations.Profile is the basic data for studying strata,rock mass and structure,so the study of the South China Sea section is of great significance for deep geological tectonic evolution and oil and gas exploration.Firstly,this paper collects,summarizes,collates and summarizes the geological conditions,drilling data,stratigraphic characteristics,rock physical property,basin distribution and characteristics of the South China Sea and the peripheral regions.Seawater layer correction,bouguer correction and sedimentary layer correction were carried out on the Satellite gravity anomaly data from the south China sea,and the bouguer gravity anomaly was obtained.Then,the inversion method of the potential field interface is used to calculate the bouguer gravity anomaly to obtain the Moho depth distribution in the South China Sea.Processing of satellite magnetic data in the South China Sea to summarize the characteristics of magnetic anomalies in the South China Sea region.Secondly,it focuses on the treatment of eight gravity magnetic seismic profiles in the South China Sea and makes a qualitative and quantitative explanation,and draws the following conclusions: 1.Through the analysis and research of eight gravity magnetic seismic sections,three areas are divided into three parts: the continental crust,the transitional zone and the oceanic crust.2.The Mohosurface and Curie surface of the land area is deep.The Moho surface of the New South China Sea Basin is shallow and the depth of the Curie is also shallow.It is consistent with the expansion of the South China Sea.3.There is little difference in the crustal density structure between the north and south sides of the New South China Sea.It is speculated that the Middle Paracel Basin and the Reed basin belong to the same tectonic unit before the Southwest Sub-basin is opened.4.The Eastern Sub-basin is closer to the expansion center of the South China Sea.Because the old strata are melted by magma st the open stage of the South China Sea.Therefore,the remaining old strata are less,the geochron stratigraphy is relatively new,and the normal fault slopes toward the mid-ocean ridge.The sediment thickness of the Eastern Sub-basin is larger than that of the Southwest Basin,so we know the Eastern Sub-basin opened earlier than the Southwest Basin.