ORIGIN AND EVOLUTION OF THE SHUANGFENG BASIN OF THE SOUTH CHINA SEA AND THEIR CONSTRAINTS ON STRUCTURAL STYLES

The deep-water area of the northern South China Sea, i.e the Shuangfeng Basin in other words, has gradually become a hot spot for oil and gas exploration. Over the others, it is of great significance to carry out the study of structural style so as to know better about the origin and evolution of the basin. Using the 2D seismic data from Guangzhou Marine Geology Survey, the main structural styles of Shuangfeng Basin are determined based on the detailed interpretation of seismic sequences and structures. The structural evolutionary history of the Shuangfeng Basin is then reconstructed with the technique of balanced section. The nature and genesis of Shuangfeng Basin are also analyzed together with regional tectonic background in the north of South China Sea. It is revealed that the Shuangfeng Basin is a depression related to thermal subsidence of oceanic crust. Since the Shenhu movement, the basin has experienced a complete tectonic cycle from continental fracturing, through continental disintegration to seafloor spreading. The Shuangfeng Basin is formed under the action of continuous extensional tectonic stress. There are four types of extensional structural styles: extensional, transition-extensional, gravity sliding structure, and igneous structures.