CHARACTERISTICS OF GEOPHYSICAL FIELDS AND DEEP STRUCTURES OF NORTHWESTERN SOUTH CHINA SEA
YANG Tian, WU Shimin, LIU Hailing and ZHOU Di (CAS Key Laboratory of Marginal Sea Geology and South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou GD 510301, China)
On the basis of processing of geophysical data on northwestern South China Sea, map of free air gravity anomalies, Bouguer gravity anomalies, magnetic anomalies, the RTP magnetic anomalies were obtained, and the characteristics of the geophysical fields in this area were analyzed. Inverted calculation was conducted on the crustal structure of the study area based on gravity data. The results show that the Moho depth varied from 38 km to 10 km from north to south, which indicates that the crust changed from continental to transitional and finally to oceanic. The Curie interface depth was calculated based on the magnetic data, and the results show that the Curie interface depth varied from 11 to 27 km. The Curie interface ranges between the top interface of lower crust and the Moho discontinuity below the land, but is near the Moho discontinuity below the ocean.