Processing On Gravity And Magnetic Data Of South Yellow Sea And Research On Fracture System

The South Yellow Sea communicates with the North Yellow Sea in the north and the East China Sea in the south. It is a polycycle basin surperimposion forming on the pre-Sinian metamorphic rock basement of the Lower Yangtze Platform.Presently,researches indicate that the South Yellow Sea stretches across Sino-Korean Block,Yangtze Block and South China Block and the regional structure is complex and it is the only one area which hasn't any productive pool in China adjacent seas. It still has the frontier disputes about maritime space and the oil and natural gas resources with South Korea. It is significant to research the North Yellow Sea on doing theoretical research, exploiting marine resource and safeguarding marine rights and interests. Because exploration and research on this area is poor, little knowledge is acquired about this area. So reinforcing researches should be implemented.Many data were collected, including gravity and magnetic data in South Yellow Sea. Data were processed with traditional methods. Then, upward and downward continuation maps of gravity and magnetic anomalies are gained, so are the derivative anomaly maps. The gravity and magnetic anomaly are described and interpreted. The fault system of the South Yellow Sea is discussed based on the results obtained by processing data traditionally and analysing through wavelet transform and multi-scale decomposition. The characteristic of the regional geological structure is interpreted, using geology and geophysics means, according to the feature of the structure and the geophysical field. And then,the tectonic evolution of the South Yellow Sea is discussed. And several conclusions are obtained as follows:1) The fracture formations are highly developed in this area and the main tendency is NE—NEE, which is the result of the Pacific-ocenic plate's extrusion. Besides, in this area the faults of different tendencies (e.g. NE,NEE,NW,EW and NS) intermesh and cross mutually, which indicates that multiple-period tectonic reformation occur in the South Yellow Sea.2) It's proved that the west marginal fault zone of the Korean Peninsula exists really;it is shown that the Center Fault in Yellow Sea should be one fault in NW direction.3) The South Yellow Sea basin is a serial residue basin, with constantly transference, superposition and reconstruct from late Proterozoia. And it has acomplicated course of tectonic evolution.