| Being one of the most perspective oil & gas bearing basins in the shelf of China, the Shelf Basin of East China Sea locates along the eastern coast of Zhejiang and Fujian province, its east is the Pacific Ocean, its south is Taiwan Strait and its north adjacent to South Huanghai Basin. Science 1970s, large amounts of geological & geophysical surveying work have been conducted in this area by the Ministry of Geology, China Offshore Oil Corporation, China Oceanic Bureau, Chinese Academy of Science, SINOPEC and other units, more than 20 drills have been finished and oil & gas resources were found in the Longjing structural belt of Zhejiang Changyuan. More and more attention will be put in this area while the international competitive bidding and oil & gas development in East China Sea.At present, the regional geology of East China Sea including the structural features, basin style, the formation, growing mechanism and sedimentary evolution of the Shelf Basin, the basic petroleum geology including the producing, burying and preserving conditions of the oil & gas reservoir in East China Sea, even the main surveyed target Neogene strata, all are fairly studied. However, the geological structures and the sedimentary characteristics of the deep strata beneath the Neogene strata in the Shelf Basin, as well as the Mesozoic and Paleozoic problems, have not been clearly revealed and studied. In recent years, put forward by Academician Liu Guangding and approved by Premier Wen Jiabao, the oil & gas problem of Pre-Cenozoic residual basins, has been followed with interest. Therefore, it is quite important to study the geological problems of Pre-Cenozoic.Stemming from the projects of national major research program of 973, the key problems of formation & evolution and resources of Chinese marginal seas, the dissertation emphasizes on the studies of Pre-Cenozoic geological problems of the Shelf Basin in East China Sea. So firstly, the related finished achievements in this area by the Ministry of Geology, China Offshore Oil Corporation and other units were extensively collected. Then qualitative analyses were made concerning the gravity, magnetic, seismic, geo-thermal data and other geological & geophysical data in the studied area. Systematically studies about the structural evolution, sedimentary environment, geology of neighboring area, characteristics of the geophysical fields, were subsequently carried out. Technical route was finally determined in accordance with the solution of Pre-Cenozoic geological problems in the Shelf Basin of East China Sea, that is, taking integrated geological & geophysical study using gravity and magnetic data.In this technical route, several principles proposed by Academician Liu Guangding are followed: directed by tectonic historical unstable theory, using the measures of integrated geophysics, grasping two links of rock physical properties and physical-geological models, to fulfill the three combinations of geology and geophysics, qualitative and quantitative analyses, forward modeling and inversion calculation by multiple feedbacks.In methodology series, the combinations such as the gravity & magnetic and seismic, processing and interpretation, interpretation of plane and profile, processing of potential field and graphics, classical and new methods, are all studied in the dissertation. Moreover, the processing and interpretation methods using deep materials to constrain shallow strata and spreading the land results to marine areas, are also tested and put forward.Using the measures and results including gravity & magnetic anomalies in different height continuation, detail and approximate fields of wavelet in different orders, processing of 3-dimentional Euler deconvolution in different structural exponents, the local field and regional field are separated and studied through the series processing including the Bouguer gravity anomalies in East China Sea and its adjacent areas, the gravity & magnetic anomalies in the Shelf Basin of East China Sea. Then the tectonic features of Cenozoic and Pre-Cenozoic are deduced. Furthermore, the basement faults, using horizontal derivatives in different directions and the reinforced processing technique of cubic shadow images in different angles, are focally studied. The tectonic units are also divided using geological, drillings and other geophysical materials.The thoughts and principles of integrated geological & geophysical interpretation are emphasized and embodied through the data processing and interpretation in the dissertation. The depth and lithology of the sedimentary basement of the Shelf Basin in East China Sea are revealed by plane and profile inversion results using the methods of integrated models and stripping on the basis of the construction of typical geological-physical models. Among them, two gravity & magnetic and seismic integrated interpretation profiles, YD506 and D224, with the total length of 627km, were processed; the depth, the apparent magnetization intensity and the apparent density of the gravity & magnetic basement are also carefully calculated by inversion within a area of 69593 km~2 in the uplift of Haijiao and its adjacent areas, the intensity and lithology of the sedimentary basement in the studied area, the thickness of Mesozoic and Paleozoic, are also deduced.In the dissertation, the faults of the Cenozoic sedimentary basement are delimited in accordance with the interpretation results of geophysics and geology, land and marine. Then the tectonic division of the sedimentary basement is made. It lays stress on the lithology and times of the basement and the Mesozoic distribution with two different styles, which is different from the results of former studies that mainly deduced by Cenozoic sediments. Based on the above achievements and taken the Mesozoic as the principal thing, the tectonic evolution of the Shelf Basin in East China Sea are focally discussed.Views concerning two problems are put forward in the dissertation, one is about the distribution range of the Cenozoic basin in the Shelf basin of East China Sea, the second is about the tectonic layout represented not only in Cenozoic but also in Pre-Cenozoic with the difference and characteristics of belt-shaped in east and west direction and block-shaped in south and north direction.The studied achievements of the dissertation bear certain theoretical and important applicable values not only for the Pre-Cenozoic geology, the Mesozoic distribution and tectonic evolution of the Shelf Basin in East China Sea, but also for the oil & gas exploration of the Pre-Cenozoic residual basins.
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