Research On Gravity And Magnetic Field And Structural Feature Of The South Yellow Sea Basin

The South Yellow Sea Basin is located between the shallow continental shelf which is mainland China and the Korean Peninsula. A lot of work have been already done about basic geology and petroleum geology study in the South Yellow Sea Basin. Existing researches indicate that the regional structure of the South Yellow Sea is complex and it still belongs to petroleum basin which dosen t make an important breakthrough in oil and gas. Presently the exploration and research level in the South Yellow Sea Basin is low. especially the research for the structural system applied geophysical data of the basin is not enough. It still has the disputes about fracture development and structure characteristics in the basin. So combining the predecessor research results, systematically taking advantage of the gravity and magnetic data which has been completed conducts research on fracture system, the development characteristics of stratum and the magnetic substance distribution for the basin, which can provide geophysical basic data for the further correlational research on basin. It is of great significance.In this research, the existing gravity and magnetic data are systematically collected, collated and analyzed. The basic maps of gravity and magnetic anomalies are compiled about the South Yellow Sea basin. By processing and interpreting the gravity and magnetic data, combining with the earthquake and the results of regional geological research, the fracture system is determined and the control action of the main deposits within basin on faults is researched. The scope of developing magnetic substance in the research area is delineated’ and the research area is divided tectonic units.The main results and conclusions are obtained in this research as follows:(1) The South Yellow Sea Basin has complex structure and developing fault. Cutting relationship is complicated. The main part of older faults is NE trending, and NEE trending is more for new faults. Meanwhile, NW. NNW. EW and near SN trending are developing.(2) The main part of the basement is pre-sinian metamorphic rock in the study area. Basement depth is relative shallow in Qian liyan uplift, the central uplift and Wunansha uplift while the north depression and the south depression deeper. Multiple depocenters develop in the study area. The shallowest buried depth of Palaeozoic group is located in Wunansha uplift the deepest buried depth in the north depression and the south depression. Mesozoic group develop thinner in the uplift, and thicker in the depression. Cainozoic group is widely distributed in the district.(3) Macroscopicly, the magnetic substance anomaly is NE trending, and part of them is NW trending. In study area, the magnetic substance anomaly is mainly distributed in the northwest, east and southeast.(4) The South Yellow Sea Basin can be divided into eight structural units, which are Qian liyan uplift, the north depression, the northeast depression, the central uplift, the south depression, Wunansha uplift, the east depression and the east uplift.